Wiadomości Chemiczne

Wiadomości Chemiczne, 2012, Vol.66

Back   |  Home page

  1. Quantum Chemistry in Molecular Nonlinear Optics
    Małgorzata Wielgus, Justyna Kozłowska, Wojciech Bartkowiak

  2. Bioglasses and Organic-Inorganic Composites for Bone Tissue Engineering
    Łukasz John

  3. Mesoporous Polymeric Materials, The New Family Of The Molecular Sieves
    Witold Bożejewicz, Jakub Dzitko, Stanisław Kowalak

  4. Monosaccharide Ring Conformations
    Łukasz Stępień, Beata Liberek

  5. Biocatalytic Methods for Preparation of Nonracemic Arylallylic Alcohols
    Sara Szymkuć, Ryszard Ostaszewski

  6. Nucleic Acids as Catalysts in Chemical Reactions
    Małgorzata Bukowiecka-Matusiak, Marta Sobczak

  7. Essential Oils as an Active Ingredients or Preservativies in Cosmetics
    Michalina Adaszyńska, Maria Swarcewicz

  8. W 150-lecie zjazdu niemieckich przyrodników i lekarzy w Speyer
    Ignacy Z. Siemion

  9. Ion Binding to Interfaces and Specific Ion Effects
    Anna Jakubowska

  10. Surfactants - Application and Micelle Formation
    Anna Jakubowska

  11. Microporous Metal-Organic Frameworks for Hydrogen Storage
    Joanna Czub, Łukasz Gondek, Henryk Figiel

  12. Combustion Synthesis of Tungsten, Tantalum, and Molybdenum Nanopowders
    Stanisław Cudziło, Magdalena Czugała

  13. Asymmetric Transfer Hydrogenation of Ketones Catalyzed by Ruthenium(Ii) and Rhodium(Iii) Complexes
    Aleksandra Karczmarska-Wódzka, Renata Kołodziejska, Renata Studzińska, Marcin Wróblewski

  14. Synthesis and Biological Activity of 2,6-Naphthyridine Derivatives
    Anna Wójcicka, Edwin Wagner

  15. Synthesis of Adenosine Analogues
    Monika Samsel, Krystyna Dzierzbicka

  16. E-Chemistry at School
    Piotr Wojciechowski

  17. The Structure of Benzo[b]Furan and Courmarin Derivatives and their Copper(Ii) and Zinc(Ii) Complexes
    Aleksandra Drzewiecka

  18. O kreatywnym autyzmie
    I. Z. Siemion

  19. Biological Applications of Lanthanide Doped Nanomarkers
    Małgorzata Misiak, Katarzyna Prorok, Artur Bednarkiewicz

  20. Investigation (Detection) of Microbal Environmental Contamination by Mass Spectrometry.
    Part I. Muramic Acid as a Biomarker of the Microbial Cell Walls

    Zbigniew Mielniczuk, Karol Bal

  21. Methods for the Synthesis of 2,2'-Bipyrrolidine
    Katarzyna Eichstaedt

  22. 2,2'-Dihydroxy-1,1'-Binaphthyl (Binol) and its Derivatives: Selected Synthesis Methods and Applications. Part I.
    Dorota Krasowska

  23. Hypervalent Compounds of Sulfur, Selenium and Tellurium.
    Part 1. General Characteristics

    Adrian Zając

  24. Selected Cooling Compounds Used in Cosmetics
    Michalina Adaszyńska, Maria Swarcewicz

  25. Bioactive Compounds in Wine
    Jan Małyszko, Monika Karbarz

  26. Hypervalent Compounds of Sulfur, Selenium and Tellurium. Part 2. Sulfuranes 10-S-3 and 10-S-4
    Adrian Zając

  27. Peroxynitrite a Strong Biological Oxidant
    Michał Bijak, Michał Błażej Ponczek, Joanna Saluk, Marta Chabielska, Julita Stępniak, Paweł Nowak

  28. Chemical Aspects of Targeted Anticancer Therapy. II. Bond of Carrier to Drug
    Karolina M. Werengowska, Marek Wiśniewski, Artur P. Terzyk, Natalia Gurtowska, Tomasz A. Drewa, Joanna Olkowska

  29. The Route Against the Sun. Early History of Vitamin D
    Jerzy Wicha

  30. Inorganic Nanoparticles in Nuclear Medicine
    Agata Kasperek, Aleksander Bilewicz

  31. Maya Blue, One of the Most Important Achievements of Mesoamerica
    Małgorzata Łukarska, Anna Zywert, Stanisław Kowalak

  32. Libraries of Chemical Compounds
    Krzysztof M. Zwoliński, Zbigniew J. Leśnikowski

  33. Avogadro Project (IAC) and Redefinition of the Mole
    W. T. Chyla

  34. O "Układzie Okresowym" Primo Levi'ego
    Ignacy Z. Siemion

  35. Biological Activity of 2-Amino-1H-Benzimidazole Derivatives. Part I
    Wanda Paulina Nawrocka, Anna Nowicka, Hanna Liszkiewicz

  36. Biological Activity of 2-Amino-1H-Benzimidazole Derivatives. Part II
    Wanda Paulina Nawrocka, Anna Nowicka, Hanna Liszkiewicz

  37. Studies on the Structure and Dynamics of N-Terminal Sequences of Dermorphin and their Analogs by Means of Solid State NMR Spectroscopy and XRD
    Katarzyna Trzeciak-Karlikowska

  38. Hypervalent Compounds of Sulfur, Selenium and Tellurium. Part 3. Martin Sulfurane, Sulfuranes 10-S-5 and 12-S-6
    Adrian Zając

  39. Biomaterials for Tissue Engineering and Regenerative Medicine
    Maria Nowacka

  40. Methods for the Synthesis of Organic Derivatives Containing the Triple Bond Carbon-Carbon
    Irena Bylińska, Katarzyna Guzow

  41. Derivatives of 1,2,3-Triazole. Potential Drugs?
    Emilia Bankowska, Andrzej E. Wróblewski

  42. Biological Synthesis of Metal Nanoparticles
    Irena Maliszewska

  43. Isoxazolidine Analogues of Nucleosides
    Kamil Kokosza, Dorota G. Piotrowska

  44. Synthesis, Structures and Biological Activity of Imidazo[4,5-b]Pyridine Derivatives. Part 1
    Hanna Liszkiewicz, Anna Nowicka, Wanda Paulina Nawrocka

  45. The Proteolytic Machinery and its Regulators
    Julia Stój, Przemysław Karpowicz

  46. Hypervalent Compounds of Sulfur, Selenium and Tellurium. Part 4. Selenuranes and Telluranes
    Adrian Zając

Back   |  Home page


QUANTUM CHEMISTRY IN MOLECULAR NONLINEAR OPTICS

Małgorzata Wielgus, Justyna Kozłowska, Wojciech Bartkowiak

Zakład Chemii Teoretycznej, Instytut Chemii Fizycznej i Teoretycznej, Politechnika Wrocławska Wybrzeże Wyspiańskiego 27, 50-370 Wrocław e-mail: wojciech.bartkowiak@pwr.wroc.pl


We review quantum-chemical methodologies based on simple two- and three-state models for molecular hyperpolarizabilities and two-photon cross-sections. In this article we show that simplified few-state models, obtained from sum-over-states formalism, are important tools for investigations structure-property relationships for various type of p-conjugated compounds. These relationships are important for rational design of molecules with large nonlinear optical response.

Keywords: (hyper)polarizability, two-photon absorption cross section (TPA), resonant optical processes, nonresonant optical processes, sum-over-states method, two-state model, three-state model, charge-transfer, nonlinear optical response, bond length alternation (BLA)


Wiadomości Chemiczne, 2012, 66, 1.
Back   |  Home page

 


BIOGLASSES AND ORGANIC-INORGANIC COMPOSITES FOR BONE TISSUE ENGINEERING

Łukasz John

Wydział Chemii Uniwersytetu Wrocławskiego, ul. F. Joliot-Curie 14, 50-383 Wrocław, Polska
e-mail: lukasz.john@chem.uni.wroc.pl


The most demanded biomaterials for bone tissue engineering could be classified in two main sol-gel derived groups: bioglasses and organic-inorganic composites. The first of these include bioactive ceramics such as calcium phosphates (Tab. 2) [1], glasses and glass ceramics [2], and so-called inert ceramics (Tab. 1) such as Al2O3, zirconium and titanium dioxide, and carbon-based materials [3, 4]. Second-group of compounds constitute bioactive organic-inorganic hybrids, generally based on organic matrix and various inorganic dopants. Biomaterials in contact with human plasma and bone stem cells form, on their surface, hydroxyapatite Ca10(PO4)6(OH)2 (HAp) and its derivatives (Tab. 2). HAp-layer initiates bone growth and reconstruction of treated fragment (Fig. 2). These materials, due to the high degree of biocompability are considered as the most valuable compounds for bone surgery [5]. Extremely rapid development of biomaterials used in medicine caused the production of implants with different properties (Scheme 1). The real revolution and technological progress have brought biomimetic composites that mimic naturally occurring solutions in living organisms. The role of such implants is not only replacing the damaged parts of body, but - due to the appropriate morphology and composition - stimulating the growth of living cells (Fig. 3) and final bone regeneration. This article is devoted to this type of biomaterials proposed for bone tissue engineering.

Keywords: biomaterials, bioglasses, organic-inorganic hybrid, hydroxyapatite, bone implants, scaffolds, in vitro


Wiadomości Chemiczne, 2012, 66, 21.
Back   |  Home page

 


MESOPOROUS POLYMERIC MATERIALS, THE NEW FAMILY OF THE MOLECULAR SIEVES

Witold Bożejewicz, Jakub Dzitko, Stanisław Kowalak

Uniwersytet A. Mickiewicza w Poznaniu, Wydział Chemii, ul. Grunwaldzka 6, 60780 Poznań
e-mail: wektor@amu.edu.pl


The great and always growing family of the molecular sieves comprises mostly inorganic adsorbents such as microporous, crystalline zeolites, zeolite-like materials as well as ordered mesoporous substances. In recent decades, however, the new generations of inorganic-organic molecular sieves have been discovered such as MOF (Metal Organic Framework) and PMO (Periodic Mesoporous Organosilicas). The youngest group of the molecular sieves is a fully organic system of ordered porous resins. Although the organic molecular sieves show lower thermal stability than conventional inorganic materials they seem very interesting and promising due to possible variety of mesoporous structures and great ability of modification by altering their composition and substitution of various functional groups.

The novel materials can be synthesized from different precursors although resols obtained by condensation of phenol and formaldehyde are most frequently applied. The porous structure can be obtained by adding the porogeneous agent into the polymerization mixture. The surfactants as well as triblock copolymers (Pluronics) are often used as such agents. They are thermally removed from the final product after completing the polymerization and thermal crosslinking. There are also successful attempts to apply a nanocasting for organized assembling the resin upon its formation. The functional groups can be formed either by adding the functionalized substrate into polymerization mixture or by introduction of chosen groups into resulted polymeric product. Extended thermal treatment of resulted porous resins at high temperatures often results in their carbonization which leads to formation of ordered porous carbons. Many authors drive their attention to produce the active carbons via the stage of porous resins.

The new family of the molecular sieves can be applied as selective adsorbents or membranes, but it is also likely that they could appear efficient catalysts (similarly as well known ion-exchange disordered resins).

Keywords: mesoporous polymer resins, structure, synthesis, properties, applications


Wiadomości Chemiczne, 2012, 66, 41.
Back   |  Home page

 


MONOSACCHARIDE RING CONFORMATIONS

Łukasz Stępień, Beata Liberek*

Wydział Chemii, Uniwersytet Gdański, ul. J. Sobieskiego 18, 80-952 Gdańsk
*e-mail: beatal@chem.univ.gda.pl


Conformational studies of the pyranose and furanose rings are important and have been carried out for years. Knowledge of the conformation of monosaccharide is essential for understanding its physical, chemical and biological properties. Additionally, conformation of the sugar ring plays a crucial role in the stereochemistry of the reaction in which it participates.

This paper provides a basic knowledge concerning the conformational preferences of a monosaccharide ring. The pyranose ring conformations are defined with reference to a cyclohexane ring [1-3]. Factors influencing stability of the pyranose chair conformation are discussed: the 1,3-diaxial interactions [4-6] and anomeric effect [7-10]. It is shown how to estimate the relative stabilities of the two chair conformations on the basis of the Angyal destabilizing factors [11, 12]. It is also demonstrated how to use the NMR spectroscopy for conformational analysis [13-23].

Conformations of the unsaturated pyranose rings are defined and studied mainly on the glycals [24-29], the monosaccharides with a double bond between the C1 and C2 carbon atoms. Factors influencing stability of the unsaturated pyranose ring are disscused: the allylic effect [30] also named the vinylogous anomeric effect [31-34], and quasi 1,3-diaxial interactions [35, 36].

Finally, the furanose ring conformations and pseudorotational itinerary for a D-aldofuranose ring are presented [37]. Two parameters defining the furanose ring conformation are introduced: the amplitude of pseudorotation [38, 39], named also the maximum torsion angle [4] and pseudorotational phase angle [4]. The possible ways to study the conformation of the furanose ring are disscused [40-44].

Keywords: conformation, pseudorotation, equatorial orientation, 1,3-diaxial interactions, anomeric effect, allylic effect, vinylogous anomeric effect, coupling constant


Wiadomości Chemiczne, 2012, 66, 67.
Back   |  Home page

 


BIOCATALYTIC METHODS FOR PREPARATION OF NONRACEMIC ARYLALLYLIC ALCOHOLS

Sara Szymkuć1, Ryszard Ostaszewski2

1 Wydział Chemiczny Politechniki Warszawskiej, ul. Noakowskiego 3, 00-664 Warszawa
2 Instytut Chemii Organicznej Polskiej Akademii Nauk, ul. Kasprzaka 44/52, 01-224 Warszawa
e-mail: rysza@icho.edu.pl


Different methods for preparing nonracemic arylallylic alcohols are presented in this work. A key feature was an application the biocatalyst as a mean to obtain final products. These compounds play an important role in pharmaceutical industry, because they are substrates in the synthesis of various important therapeutics [1-3]. Methods presented in this work are divided into five main groups:

  1. enantioselective hydroxylation,
  2. microbiological deracemization,
  3. enzymatic kinetic resolution,
  4. enzymatic dynamic kinetic resolution,
  5. enantioselective reduction.

First two methods use only microorganisms like bacteria [4, 5, 10], fungi [6-8] or yeasts [11] as biocatalysts. Owing to the metabolic processes in the cells it was possible to obtain nonracemic arylallylic alcohol (results for method 2 are presented in Table 1). Unfortunately, the data were insufficient to create direct correlation between values of enantiomeric excess and types of applied microorganisms.

Methods 3 and 4 used only isolated enzymes as biocatalysts. They belong to two classes: hydrolases and oxidoreductases. Oxidoreductases were used in the enzymatic kinetic resolution based on the enantioselective oxidation [28] of one enantiomer of the racemic arylallylic alcohol. Nevertheless, hydrolases [12-27], mainly lipases, isolated from microorganisms are enzymes of common use in enzymatic kinetic resolution. Owing to this method it was possible to obtain final products with excellent enantioselectivity (results are presented in Tables 2 and 3). Because kinetic resolution and dynamic kinetic resolution are related processes, in most cases similar enzymes are used. The choice of lipases as biocatalysts for method 4 was caused by the fact that they are able to catalyze enantioselective transesterification of arylallylic alcohols or their acetates. Furthermore, racemization is very important factor for efficacy of dynamic kinetic resolution processes. In most cases they are catalyzed by different types of complexes based on palladium [30, 31] and ruthenium [32, 34]. Final products prepared by this method had very high enantiomeric excesses and yields up to 93% (results are presented in Tables 4 and 5).

The only method, presented in this work, that allowed to use both enzymes [39-41] and microorganisms [35-38] as biocatalysts, was enantioselective reduction. This method allows to obtain nonracemic arylallylic alcohols with excellent enantiomeric excess and yields up to 85% (results are presented in Table 6).

In summary, all methods presented in this work show the advantages of biocatalysis as an alternative route to traditional chemical methods.

Keywords: biocatalysis, nonracemic arylallylic alcohols, organic synthesis, enzymes, microorganisms


Wiadomości Chemiczne, 2012, 66, 93.
Back   |  Home page

 


NUCLEIC ACIDS AS CATALYSTS IN CHEMICAL REACTIONS

Małgorzata Bukowiecka-Matusiak1*, Marta Sobczak2

1 Zakład Biologii Strukturalnej, Wydział Nauk Biomedycznych i Kształcenia Podyplomowego, Uniwersytet Medyczny w Łodzi, ul. Żeligowskiego 7/9 90-752 Łódź
e-mail: malgorzata.bukowiecka-matusiak@umed.lodz.pl
2 Wydział Nauk Biomedycznych i Kształcenia Podyplomowego, Uniwersytet Medyczny w Łodzi
e-mail: m_sobczak@op.pl


Nucleic acids, due to their specific structure, are effective and durable carriers of genetic information. They have also been used as catalysts in chemical reactions. The right-handed DNA double helix structure has become one of the icons of modern science, and its share in asymmetric catalysis is undeniable.

In these reactions, DNA is a source of chirality and proximity between oligonucleotides and complexes of copper during catalysis, what allows a direct transfer of chirality from DNA to the reaction product. Almost complete regioselectivity and excellent enantioselectivity of the aforementioned reactions in water are the evidence of the potential of asymmetry based on DNA.

Asymmetric catalysis used in organic synthesis, allows achieving high enantioselectivity. This strategy has been successfully used to create new C-C bonds in Diels-Alder cycloaddition, Friedel-Crafts alkylation and Michael addition using copper complexes with oligonucleotides as catalysts.

The important factor to optimize the reaction of asymmetric catalysis in the presence of DNA constitutes its sequence. It has been shown that the use of the double helix DNA can provide the product with higher enantiomeric excess than using the single strand of DNA.

In addition, the results of the study suggest that Friedel-Crafts alkylation is accelerated by DNA almost 30-fold. The same correlation is observed in Diels-Alder cycloaddition.

Due to promising results, further testing directed at the possibility of using catalytic DNA is being conducted.

Keywords: DNA, catalysis, asymmetric synthesis


Wiadomości Chemiczne, 2012, 66, 119.
Back   |  Home page

 


ESSENTIAL OILS AS AN ACTIVE INGREDIENTS OR PRESERVATIVIES IN COSMETICS

Michalina Adaszyńska, Maria Swarcewicz

Zakład Syntezy Organicznej i Technologii Leków, Wydział Technologii i Inżynierii Chemicznej, Zachodniopomorski Uniwersytet Technologiczny w Szczecinie, Al. Piastów 42, 71-065 Szczecin
e-mail: michalina.adaszynska@gmail.com; mswar@zut.edu.pl


An important trend in current cosmetic industry is increasing demand for new, biologically active compounds and preservatives of natural origin. These products constitute a major ingredients of natural (organic) cosmetics and usually may also be used in typical cosmetics as functional additives. This work summarizes the perspectives of the use of essential oils as active ingredients and preservatives in cosmetic products and as biopesticides. Brief characteristics of essentials oils, their preparation and biological activity is provided. Literature data suggests that essential oils exhibit broad therapeutic effects including antibacterial, antiseptic, antifungal and antioxidant activity, they can be also used as transdermal enhancers. On the other hand, in essential oil have been found compounds which can be use as a biopesticides.

The use of essential oils in cosmetic products is possible, but requires a detailed knowledge regarding their compatibility, active concentration as well as toxicological and skin irritant characteristics. The literature review, presented in this paper, shows the great potential of essential oils as a biologically active preservatives and antioxidants, repellents and transepidermal enhancers.

Keywords: essential oils, alternative and natural preservation, antimicrobial activity, antioxidant activity, biopesticides


Wiadomości Chemiczne, 2012, 66, 139.
Back   |  Home page

 


W 150-LECIE ZJAZDU NIEMIECKICH PRZYRODNIKÓW I LEKARZY W SPEYER

Ignacy Z. Siemion

Wydział Chemii Uniwersytetu Wrocławskiego, ul. F.Joliot-Curie 14, 50-383 Wrocław



Wiadomości Chemiczne, 2012, 66, 183.
Back   |  Home page

 


ION BINDING TO INTERFACES AND SPECIFIC ION EFFECTS

Anna Jakubowska

Zakład Chemii Fizycznej, Wydział Chemii, Uniwersytet im. Adama Mickiewicza, ul. Grunwaldzka 6, 60-780 Poznań
e-mail: annajak@amu.edu.pl


Many biological processes taking place across or at membrane surfaces depend on the interaction between interfaces and ions (derived from the background salt) [1]. Binding of ions to surfactant bilayers, nucleic acids, proteins, and biological membranes markedly affects their stability and properties [2-8]. There are different techniques to measure the ion binding to interfaces, including: nuclear magnetic resonance (NMR) spectroscopy [2, 18-20], the method based on measuring of electrophoretic mobility and the so-called zeta potential measurements [4, 21], the method based on measuring of a ratio of acid-to-base forms of the spectrophotometric indicator pyridine-2-azo-p-dimethylaniline, PADA [12], and the chemical-trapping method [22]. The above-mentioned methods permit investigation of the binding of either cations or anions to interfaces.

Many theories and models had been proposed to describe quantitatively the interactions and distribution of ions at a charged surface. The earliest one was proposed by Gouy and Chapman [23, 24]. However, the classical Gouy-Chapman theory was too simplified due to the neglect of the geometrical dimensions of the ions [27]. Other theories have been developed on the basis of the Poisson-Boltzmann theory and the Poisson-Boltzmann equation (equation 3). This equation has been modified by an introduction of different terms [25, 42]. Recently, Radke et al. proposed interesting models of the ion distribution near the interface: the ion binding model [28] (Fig. 1) and the ion image charge interaction model [51] (Fig. 3).

Interaction and binding of ions with interfaces is related to the so-called specific ion effects arising at exchanging ions of the same valence. Franz Hofmeister, Professor of Pharmacology at the University of Prague was the first who studied these effects systematically [13, 14]. The specific ion effects play a significant role in a wide range of biological and physicochemical phenomena from the salt solubility, electrolyte activities, the surface tension of electrolyte solutions, values of pH and zeta potentials, the buffer acting, microemulsion microstructure, cloud points of polymers and surfactant solutions to the action of ions on ion-channels in biological membranes (ion transport across membranes), in enzyme activities, in bacterial growth, and in the interaction between membranes [15, 16]. The biological cell activity is also connected to Hofmeister effects. The ion specificity observed is, in fact, a combination of different subtle effects, such as ion size, hydration of ions, ion effect on interfacial water structure, electrostatic and dispersion interactions, thermal motion, and fluctuations [26, 29-31]. Because of a combination of those different effects, Hofmeister effects remain unexplained by the present theories of physical chemistry [16].

Keywords: binding of ions, research methods, theories and models, specific ion effects, occurrence, characterisation


Wiadomości Chemiczne, 2012, 66, 193.
Back   |  Home page

 


SURFACTANTS - APPLICATION AND MICELLE FORMATION

Anna Jakubowska

Zakład Chemii Fizycznej, Wydział Chemii, Uniwersytet im. Adama Mickiewicza, ul. Grunwaldzka 6, 60-780 Poznań
e-mail: annajak@amu.edu.pl


Surfactants are surface active agents which belong to a wide class of amphiphilic compounds [1, 2]. Surfactant molecules generally consist of a hydrophilic head of various nature (ionic or non-ionic) and a hydrophobic tail (a hydrocarbon chain), which is usually linear or branched. The surfactant concentration at which the association of a certain number of monomers leads to the formation of aggregates (micelles) is called the critical micelle concentration (CMC) [1]. To describe the micelle formation process the mass action model and the pseudo-phase separation model are generally applied. Micelles are thermodynamically stable forms. Aggregated structures (micelles) formed by surfactant molecules (monomers) in aqueous and non-aqueous solutions are shown in Figure 2.

Surfactants and their micellar systems have immense technological applications. Surfactants are for example applied: in textile industry, in microelectronics for production of semiconductors, for production of mesoporous materials [25], in environmental research [26], as antiseptics [27], in cosmetic industry [1], as models of biological systems [28, 29, 32], for analysis of albumens [34], in pharmaceutical industry [1].

Sodium dodecyl sulfate (SDS) and cetyltrimethylammonium bromide (CTAB) are one of the most important surfactants in common use. In the last decade these surfactants were used: as ancillary means for removal of chemical pollutants from water [60], for preparation of cell electrodes [61], modification of nanoparticle size [62], modulation of fluorosensor activity [67, 70], activation of enzymes [71, 72], as stabilizers of drugs [73], in generation of chemical oscillators [74, 75], to induce changes in conformational behaviour of DNA molecules [10, 76-79].

Keywords: surfactants, micellar systems, application, micelle formation process


Wiadomości Chemiczne, 2012, 66, 209.
Back   |  Home page

 


MICROPOROUS METAL-ORGANIC FRAMEWORKS FOR HYDROGEN STORAGE

Joanna Czub, Łukasz Gondek, Henryk Figiel

AGH Akademia Górniczo-Hutnicza, Wydział Fizyki i Informatyki Stosowanej, al. A. Mickiewicza 30, 30-059 Kraków
e-mail: joanna.czub@agh.edu.pl


Currently, the metal-organic frameworks (MOFs) are considered among the most promising materials for hydrogen storage. In this paper, the properties of MOFs that are particularly important for application purposes are presented. Examples include simplicity of their syntheses on an industrial scale, low synthesis costs, high thermal stability and durability, an excellent repeatability and very low degree of degradation during cyclic hydrogen loading and recovery. On the other hand, the potential use of MOFs as hydrogen reservoirs is to some extent limited due to the fact that the low temperatures of 77 K are required for effective adsorption of hydrogen in the microporous structures of MOFs. Nowadays, the research on MOFs is carried in two directions. In particular, there are intensive studies on increasing of the concentration of hydrogen adsorbed at low temperatures in order to determine the limiting value for which maintaining the reservoir at the temperature of liquid hydrogen would be economically viable. It seems that the limiting concentration is being currently reached. The second direction of research is to increase the limiting value of temperature at which the concentration of adsorbed hydrogen is acceptable.

Keywords: metal-organic frameworks, microporous materials, MOF, adsorption, hydrogen storage


Wiadomości Chemiczne, 2012, 66, 227.
Back   |  Home page

 


COMBUSTION SYNTHESIS OF TUNGSTEN, TANTALUM, AND MOLYBDENUM NANOPOWDERS

Stanisław Cudziło, Magdalena Czugała

Wojskowa Akademia Techniczna, Instytut Chemii, Wydział Nowych Technologii i Chemii, ul. gen. S. Kaliskiego 2, 00-908 Warszawa
e-mail: scudzilo@wat.edu.pl


Refractory metal nanopowders have recently been of interest as starting materials for preparation of heavy alloys with exceptionally good mechanical properties resulting from their structure homogeneity at a nanoscopic level. In the light of recently published papers, the combustion synthesis seems to be a promising technique for the large-scale production of metal nanopowders. In this method, the self-sustaining internal combustion of energetic composites is used to produce useful materials. The energy released in the combustion wave, propagating through a pressed sample of the green mixture, causes a rapid increase in temperature which in turns enables the processes and reactions with high activation barriers to proceed. Unbalanced conditions and high time and space variability of temperature in combustion wave are conducive to the creation of compounds and structures that are difficult to produce using other methods. Thanks to this combustion synthesis there is a source of simple and complex metal oxides, ceramic materials, metals and intermetallic compounds as well as various composites of the substances, both in powdery and compact forms. The product form and its microstructure depends on the synthesis conditions, especially on the size and morphology of substrate particles, reactants ratio, the initial density, the presence and concentration of additives, temperature and external pressure [1-6]. Metal powders are typically produced by reduction of relevant oxides. Aluminum, magnesium, zinc, calcium, zirconium, titanium, silicon, carbon and their mixtures or compounds are used as reducers [11]. If the combustion temperature is excessively high (above 2000°C) coarse metal powders are usually produced. The initially formed crystallites are irregular in shape, they melt on the surface and agglomerate giving even bigger particles. To overcome this problem, alkali metal halide is included as an additional reactant in the system. The additive melts in the combustion wave, reduces the combustion temperature, aids in transportation of the main reactant species, which positively affects the size and shape of combustion product particles. In addition, molten salt prevents grain growth by forming a protective layer around the particles. The current paper reviews recently published works (mainly by H.H. Nersisyan et al. [7, 12-23]) on molten salt assisted combustion synthesis (SACR) of tungsten, tantalum and molybdenum nanopowders. A detailed description of the synthesis method including its specific features, the experimental procedure, combustion parameters and macro-kinetic aspects of chemical reactions in the combustion wave, and characterization of the metal nanopowders are presented.

Keywords: combustion synthesis, SACR, metal nanopowders


Wiadomości Chemiczne, 2012, 66, 249.
Back   |  Home page

 


ASYMMETRIC TRANSFER HYDROGENATION OF KETONES CATALYZED BY RUTHENIUM(II) AND RHODIUM(III) COMPLEXES

Aleksandra Karczmarska-Wódzka, Renata Kołodziejska, Renata Studzińska, Marcin Wróblewski

Katedra i Zakład Chemii Ogólnej, Collegium Medicum w Bydgoszczy UMK Toruń, ul. Dębowa 3, 85-626 Bydgoszcz
e-mail: akar@cm.umk.pl


Asymmetric hydrogen transfer (ATH) is one of the methods of stereoselective reduction of prochiral carbonyl compounds (Scheme 6). Complexes of the platinum group metals (Noyori catalysts) are the most common catalysts for ATH reactions. The specific structure of the Noyori catalyst allows to activate two hydrogen atoms. These atoms are transferred from donor to acceptor in the form of hydride ion and proton (Scheme 1). Depending on the used catalyst the transfer hydrogenation of ketons can proceed by direct and indirect transfer mechanism. The direct hydride transfer from a donor to an acceptor proceeds via a six-membered transition state (3) (Scheme 2). The indirect hydride transfer proceeds through the formation of an intermediate metal hydride. A monohydride (HLnMH) and or a dihydride (LnMH2) can be formed depending on the catalyst that is used (Scheme 3). In the monohydride route, the reduction proceeds in the inner sphere of the metal (four-membered transition state (4)) or in the outer sphere of the metal (six-membered transition state (5)) (Scheme 4). The proposed reduction of carbonyl compounds in the ATH reaction by Noyori catalysts uses the mechanism of the hydride ion and proton transfer from the donor to the catalyst and the formation of the monohydride. In the indirect transfer hydrogenation the hydride ion and proton are transferred from the monohydride to the acceptor (Scheme 5, 7).

ATH reactions that lead to chiral alcohols are conducted in organic solvents or in water. Hydrogen donors most often used in organic solvent reactions are propan-2-ol or an azeotropic mixture of formic acid and triethylamine (Tab. 1, 6). Sodium formate is usually used as hydrogen donor in the reactions conducted in water. Yield and enantioselectivity of the reaction depend on many factors the most important of which are: the structure of a substrate, hydrogen donor and solvent that were used, the reaction time, substrate concentration, and the S/C ratio [2]. In the case of asymmetric reduction conducted in water the solvent pH is also of great importance [3, 7, 8]. An optimal pH range depends on the type of a catalyst [7, 8]. ATH reactions conducted in water are distinguished by a shorter reaction time and higher enantioselectivity than the reactions conducted in organic solvents. In addition, catalysts used in the ATH reactions are more stable in water allowing reuse of the catalyst without loss of its activity. This paper presented examples of the use of specific catalysts in asymmetric reactions of hydrogen transfer. In particular, I drew attention to the reactions running in the aquatic environment due to the above-mentioned advantages of this solvent. The authors focused specifically on bifunctional catalysts based on Ru(II) and Rh(III) on the account of wide usage of the catalysts of that type in ATH reactions in water and their good performance [8, 9, 15, 16, 17, 19, 20, 21, 22]. p-Cymene is the most common aromatic ligand in catalysts based on Ru(II) while in the case of catalysts with Rh(III) the most common is anionic pentamethylcyclopentadienyl ligand. In both cases the second most common ligands are diamines or amino alcohols (Scheme 8). There are better performance and enantioselectivity when diamines are used as ligands. Attempts to replace diamines and amino alcohols by Schiff bases (Scheme 13) in the catalysts containing Rh(III) proved poor results due to a very low enantioselectivity of conducted reactions (Tab. 7).

Keywords: asymmetric transfer hydrogenation, Ru(II), Rh(III) complexes, chiral ligands, prochiral carbonyl compounds


Wiadomości Chemiczne, 2012, 66, 273.
Back   |  Home page

 


SYNTHESIS AND BIOLOGICAL ACTIVITY OF 2,6-NAPHTHYRIDINE DERIVATIVES

Anna Wójcicka, Edwin Wagner

Katedra i Zakład Technologii Leków, Akademia Medyczna im. Piastów Śląskich we Wrocławiu, pl. Nankiera 1, 50-140 Wrocław
e-mail: annaw@ktl.am.wroc.pl


2,6-Naphthyridine is one of the six structural isomers of pyridopyridines. This review presents most of the literature data about natural and synthetic 2,6-naphthyridine derivatives and their biological activity.

The main goal of this paper is to present various methods for the preparation of 2,6-naphthyridine analogues. Compounds containing 2,6-naphthyridine moiety can be synthesized from different substrates. Most of them have been obtained by cyclocondensation of various pyridine derivatives. During the past twenty years the biological activity of 2,6-naphthyridines have been studied. Presented compounds exhibit anticancer [21, 41], antihypertension [10], and antidepression [25] activity. Some of them can be used in the treatment of heart diseases [22], appetite disturbance, and obsessive states [43, 44]. 2,6-Naphthyridine derivatives with different molecular targets, e.g. topoisomerase [41], SERT [27], and protein kinases [21, 22] inhibitors have also been reported. Many of the 2,6-naphthyridine analogues are histamine H3 [27] and serotonine 5-HT2 [42-44] receptor antagonists.

Keywords: 2,6-naphthyridine derivatives, synthesis, biological activity


Wiadomości Chemiczne, 2012, 66, 297.
Back   |  Home page

 


SYNTHESIS OF ADENOSINE ANALOGUES

Monika Samsel1*, Krystyna Dzierzbicka1

1Katedra Chemii Organicznej, Wydział Chemiczny, Politechnika Gdańska, ul. G. Narutowicza 11/12, 80-233 Gdańsk
*e-mail: s.monika@wp.pl


Adenosine (Rys. 1) is a purine nucleoside playing an important role in human body. It is involved in key pathways such as purinergic nucleic acid base synthesis, amino acid metabolism and modulation of cellular metabolic status [1,2]. Adenosine acts through the four types of adenosine receptors: A1, A2A, A2B and A3 belonging to the G protein-coupled receptor family [3]. In physiological conditions this nucleoside is present in a micromolar range [5]. However, when metabolic stress occurs extracellular level of adenosine raises revealing its protective properties. Depending on an activated receptor subtype, adenosine demonstrates cardioprotective and neuroprotective activity during hypoxia or ischemia, it stimulates the immunological system [6, 7].

Besides many potential applications, adenosine is used mainly for the treatment of paroxysmal supraventricular tachycardia. Limitations are linked to a very short blood half-time and no receptor specificity [8]. This review is focused on novel literature data about synthesis of adenosine analogues with interesting biological activities. In order to influence adenosine receptor selectivity and pharmacokinetic properties a nucleoside structure can be modified in purine [14, 15, 17, 22, 26, 27, 35] or sugar ring [29, 32]. New interesting compounds are also synthesized by cyclisation of adenosine [36]. Modification of adenosine structure allowed obtaining compounds with targeted action: antiarrhythmic [11, 12], antinociceptive [9], antilipolytic [13], antiviral [29] or anticancer [35].

Keywords: adenosine, adenosine receptors, synthesis, adenosine analogues, biological activity


Wiadomości Chemiczne, 2012, 66, 321.
Back   |  Home page

 


E-CHEMISTRY AT SCHOOL

Piotr Wojciechowski

Wydział Chemiczny Politechniki Wrocławskie,j ul. Wybrzeże Wyspiańskiego 27, 50-370 Wrocław
e-mail: piotr.wojciechowski@pwr.wroc.pl


Nowadays dynamic development of electronically supported teaching and learning methods exerts significant influence on modern teaching of chemistry. This resulted in E-chemistry: a combination of computer science and chemistry which covers many fields of knowledge, from education of chemistry and scientific information access to computer modeling of chemical compounds and reactions (Fig. 2).

At present, majority of universities resigns from publication of printed materials for students and provide access to teaching materials published on-line. Current electronic systems offer a great variety of workspaces and channels to facilitate distribution of information to students, enhancement of face-to-face courses, e-books creation, preparation of teaching materials, tests and electronic exams, management of electronic lessons, or even creation of virtual chemistry laboratories. For instance, chemistry students have an on-line access to the chemical databases, publications and lots of software for chemistry.

An e-learning system gives a possibility of mixing various kinds of objects such as text, images, animations, quizzes, interactive applications or links to other web sites. Furthermore, adaptive courses based on cognitive trials, learning styles, and relationships between learners can enrich each other, enabling the system to provide the learners with courses which fit their needs more accurately.

There is a number of acronyms used in e-learning, often with similar meanings. Published materials and users' activities are managed by a set of dedicated computer programs called Virtual Learning Environment (VLE). An e-learning system together with a VLE can have one of the following names: Course Management System (CMS), Learning Content Management System (LCMS), Learning Management System (LMS), Managed Learning Environment (MLE), Learning Support System (LSS) or Learning Platform (LP). E-learning systems base on a computer network and provide an on-line access to educational materials, therefore e-learning can also be called Online or Mobile Education [1].

In this paper the author shows an overview of e-learning and then a specific application of e-learning of chemistry used at the Department of Chemistry at Wrocław University of Technology [2, 3, 4], presenting some practical solutions applied.

Keywords: e-learning, distance learning, e-chemistry, e-book, Moodle.


Wiadomości Chemiczne, 2012, 66, 341.
Back   |  Home page

 


THE STRUCTURE OF BENZO[b]FURAN AND COURMARIN DERIVATIVES AND THEIR COPPER(II) AND ZINC(II) COMPLEXES

Aleksandra Drzewiecka1,2 1 Środowiskowe Laboratorium Badań Rentgenowskich i Elektronomikroskopowych Instytutu Fizyki Polskiej Akademii Nauk, 02-668 Warszawa
2 Wydział Chemii Uniwersytetu Marii Curie-Skłodowskiej, 20-031 Lublin
e-mail: adrzew@ifpan.edu.pl


Selected benzo[b]furan and coumarin derivatives with proven and potential antibacterial, anticancer and antiarrhythmic activities have been investigated [1-3] (Figs. 1 and 2). The stereochemical description of their molecules in the solid and gas phase as well as intra- and intermolecular-interactions in crystals have been determined [4-6]. The structural studies of analyzed molecules indicated the planarity of the benzo[b]furan and coumarin ring systems. The oxygen or carbon atoms of the substituents, -OH, -OCH3, -C(=O)CH3 and -COOH, are nearly coplanar with the aromatic ring. The hydroxyl and acetyl groups, being in the ortho position, are coplanar with the aromatic ring and the formation of the intramolecular O-H...O hydrogen bond in all three states of matter is observed. Its strength is around 18 kcal/mol. Several conformers of studied compounds, differing in the orientation of the methoxy, acetyl and/or carboxyl groups, were analyzed. Next, the electrochemical method was used to synthesize novel copper and zinc complexes with the oxygen donor benzo[b]furan and coumarin derivatives. The Cu(II) and Zn(II) complexes have been obtained with carboxylic acids as ligands whereas hydroxy ligands reacted only with copper [6]. The geometry of metal-ligand interaction of new compounds has been determined using a single crystal X-ray crystallography and an X-ray absorption spectroscopy [7, 8]. The combination of these two methods revealed that for some compounds cation environment could depend on the form of the solid sample. In the microcrystalline zinc complexes (studied by EXAFS) the cation is penta-coordinated (ZnO5) with the Zn-O distances being ca 1.98(3) AÅ. In the recrystallized complex (analyzed by the X-ray diffraction) it was found that zinc is tetra-coordinated (ZnO4). The Cu(II) cation in the single-crystal form of the complex with the carboxylic acid 5 is penta-coordinated to the carboxylate groups and the ethanol molecule. The bridging COO- groups stabilize the dinuclear complex center Cu2O10. The powdered form of this complex is based on the Cu2O8 units, indicating the absence of the ethanol molecule in the coordination sphere. In the series of the Cu(II) complexes with the hydroxy derivatives of benzo[b]furan and coumarin a centrosymmetric coordination polyhedron of metal exhibits a square-planar geometry (CuO4). Two ligands are bonded to the copper cation via the acetyl and deprotonated hydroxyl O atoms.

Keywords: benzo[b]furan derivatives, coumarin derivatives, Cu(II) complex, Zn(II) complex, crystal structure, XAS study


Wiadomości Chemiczne, 2012, 66, 355.
Back   |  Home page

 


OKRUCHY. XXV. O KREATYWNYM AUTYZMIE

Ignacy Z. Siemion

Wydział Chemii Uniwersytetu Wrocławskiego, ul. F.Joliot-Curie 14, 50-383 Wrocław



Wiadomości Chemiczne, 2012, 66, 377.
Back   |  Home page

 


BIOLOGICAL APPLICATIONS OF LANTHANIDE DOPED NANOMARKERS

Małgorzata Misiak1,2, Katarzyna Prorok2, Artur Bednarkiewicz1,2*

1 Instytut Niskich Temperatur I BadańStrukturalnych, PAN, ul.Okolna 2, 50-422 Wrocław, Polska
2 Wrocławskie Centrum Badań EIT+, ul. Stabłowicka 147/149, 54-066 Wrocław, Polska
*e-mail: A.Bednarkiewicz@int.pan.wroc.pl


Fluorescence is one of the most commonly used methods of biodetection, mainly due to the high sensitivity, non-invasiveness, simplicity, and also due to the availability of the whole range of powerful light sources, a wide range of photodetectors, and numerous and sensitive measuring methods. From the point of view of biodetection and bioimaging, the important characteristics of such fluorophores are large Stokes shift, narrow absorption/emission lines as well as stable and efficient luminescence.

Traditional organic dyes applied in biology reveal very fast photobleaching and limited opportunities for simultaneous detection of many biomolecules, what stimulate development of new fluorescent markers. Fast and intensive development of nanotechnology and chemical engineering observed in recent years, aims at designing the nanophosphors or luminescent nanoplatforms, that demonstrate desirable properties and devised functionality. However, new phosphors are not included yet in broad practical applications, mainly because of the need to adapt the measuring apparatus so as to fully exploit their potential. From among the fluorescent nano-particles, silica dye doped nanoparticles, quantum dots, nanocolloidal metallic nanoparticles, and lanthanide doped nanoluminophores show the largest application potential. This article discusses the unique physico-chemical properties of lanthanide doped nano-particles, which beside very long luminescence lifetimes and narrow emission bands, enable to obtain a visible emission under the near infrared photoexcitation (called anti-Stokes emission), offering improved sensitivity, stability, repeatability and accuracy of the fluorescent biodetection and bioimaging methods.

In this review, physico-chemical properties of lanthanide doped nanoluminophores and many examples of their biological applications have been discussed. The first chapter presents spectral characteristics of rare-earth ions with particular regard to the mechanism of energy transfer and up-conversion, which is a fundamental difference and the decisive advantage compared with other known fluorescent markers. The luminescent properties of lantanides are demonstrated based on the most commonly used nanomaterials singly doped with Eu3+ and Tb3+ and the codoped matrices, like Yb3+-Tm3+, Yb3+-Er3+or Yb3+-Ho3+ co-doped phosphores. The features of these materials are best suited from the point of view of biodetection and bioimaging. The next chapter gives an overview of the applications of lanthanide doped nanoluminophores in biological sciences. Different types of hetero-/homo-genous tests and luminesce based sensors for pH, CO2, the level of glucose, and other analytes are presented. Then, basic aspects of bioimaging, photodynamic and thermo-therapy, nanotermometry as well as nano-bio-technology platforms have been summarized. In conclusion suggestions of new research directions and new biological applications of lanthanide doped nanoparticles have been presented.

Keywords: up-converting nanoparticles, luminescence, bioassays, biomedical applications


Wiadomości Chemiczne, 2012, 66, 393.
Back   |  Home page

 


INVESTIGATION (DETECTION) OF MICROBAL ENVIRONMENTAL CONTAMINATION BY MASS SPECTROMETRY.
PART I. MURAMIC ACID AS A BIOMARKER OF THE MICROBIAL CELL WALLS

Zbigniew Mielniczuk, Karol Bal

Centralny Ośrodek Badawczo-Rozwojowy Opakowań, ul. Konstancińska 11, 02-942 Warszawa
e-mail: mielniczuk@cobro.org.pl, bal@cobro.org.pl


Microorganisms synthesize several monomeric chemical structures that are not found elsewhere in nature, e.g. muramic acid (an amino sugar) and D-amino acids (D-alanine and D-glutamic acid) are ubiquitous in bacterial peptidoglycan (PG). Specific sugars (e.g. heptoses) and 3-hydroxylated fatty acids are found in the endotoxin (lipopolysaccharide, LPS) of gram-negative bacteria [42].

The best way to protect against environmental contamination is microbial control. Methods in current use for monitoring of microorganisms mainly include culturing and direct microscopy. However, several factors including samples collection, growth conditions, incubation temperature and interaction between different organisms all affect culturing results.

Additionally, culturing based methods can detect only viable organisms and they are also time consuming, sometimes taking days or weeks.

However, since both living and dead microorganisms express irritating and toxic structures, they should all be taken into consideration [17].

Muramic acid (MuAc), an amino sugar, has been suggested for use as a chemical marker in gas chromatography-mass spectrometry (GC-MS) determination of bacterial peptidoglycan in both clinical and environmental samples. Several derivatives of MuAc have been applied, including the alditol acetate [1, 2], aldononitrile [3], trifluoroacetyl [4] and trimethylsilyl [5], and methyl ester O-methyl acetate [6] derivatives.

Both the alditol acetate and TMS derivatives have proven suitable for the use with GC-ion-trap tandem MS [7].

The aim of our proposition is a trial of application of gas chromatography-mass spectrometry (GC-MS) method as an alternative or complement to culturing, microscopy and other assays for detection, characterization and monitoring of microbial contamination of environment (e.g. water, air, air-conditioning systems), contamination of biochemical and food production chain processes, packaging for foodstuffs etc. by direct analysis of bacterial muramic acid as a biochemical marker.

A method is described for the quantitation of muramic acid, a marker of bacterial peptidoglycan as trimethylsilyl (TMS) derivatives using GC/MS method.

The described methods are fast and simple, and can be applied for monitoring of microbial contamination directly, without prior culturing, in complex environmental samples.

This method can also be applied for testing processes of cleaning and disinfection on packaging materials or on both packaging materials/foodstuffs in order to decrease their microbial load and thus to ensure better shelf-life.

Keywords: muramic acid, peptidoglycan, gas chromatography-mass spectrometry


Wiadomości Chemiczne, 2012, 66, 445.
Back   |  Home page

 


METHODS FOR THE SYNTHESIS OF 2,2'-BIPYRROLIDINE

Katarzyna Eichstaedt

Politechnika Gdańska, Wydział Chemiczny, Katedra Chemii Organicznej, ul. G. Narutowicza 11/12, 80-233 Gdańsk
e-mail: kateichs@student.pg.gda.pl


Vicinal diamine derivatives form an interesting and significant class of organic compounds. They play an essential role as chelating agents and also as ligands for asymmetric synthesis. They are used in synthesis of biologically active substances and in supramolecular chemistry [1-11]. There has been published a great number of reviews concerning the application and synthesis of 1,2-diamines with special emphasis on their organic potential [1-11]. Without any doubt, chiral 2,2'-bipyrrolidine derivatives are representative family of these compounds. They have gained particular attention since they are widely used. A remarkably broad spectrum of synthetic exploration has been reported for these agents [4, 12-14].

This paper provides description of methods for the synthesis of chiral 2,2'-bipyrrolidine. There are only seven different approaches to obtain (R,R) or (S,S)-2,2'-bipyrrolidine, five from which take advantage of stereoselective synthesis steps [15-21]. Nevertheless, a method for the synthesis of amine-1, which connects low reagents price with low time-consuming and high yield have not been described yet. Thus, creation of a new strategy for an efficient synthesis of chiral 2,2'-bipyrrolidine is still a challenging topic of studies.

Keywords: 2,2'-bipyrrolidine, vicinal diamines, asymmetric synthesis, C2-symmetry


Wiadomości Chemiczne, 2012, 66, 461.
Back   |  Home page

 


2,2'-DIHYDROXY-1,1'-BINAPHTHYL (BINOL) AND ITS DERIVATIVES: SELECTED SYNTHESIS METHODS AND APPLICATIONS. PART I.

Dorota Krasowska

Centrum Badań Molekularnych i Makromolekularnych, Polska Akademia Nauk, ul. Sienkiewicza 112, 90-363 Łódź, Poland
e-mail: dkras@cbmm.lodz.pl


1,1'-Binaphthyl and its derivatives represent a particular class of chemical molecules which chirality results from the restricted rotation about single bond of the two naphthalene rings. This generates the chirality axis. Therefore 1,1'-binaphthyl derivatives exist as two enantiomeric forms called atropoisomers. Moreover, 1,1'-binaphthyls with substituents at 2,2' position exhibit higher rotational barriers around the 1,1'-axis, which affect a very stable chiral configuration. The classical examples of such molecules is 2,2-dihydroxy-1,1'-binaphthyl (BINOL), which has become one of the most utilized chiral ligand and auxiliary for diverse asymmetric syntheses. The unchallenged success of BINOL and its derivatives in the field of transition metal-catalyzed asymmetric reactions or C-C bond forming reactions promoted worldwide an advancement of organic synthesis. The first synthesis of BINOL as racemate was described in 1873. Since then there have been found numerous efficient methods of racemic or enantiomerically pure BINOL preparation and its derivatization. In order to present a brief overview of the most convenient and facile routes to obtain racemic and nonracemic symmetrically substituted 1,1'-binaphthyls based on stoichiometric and catalytic oxidative coupling, classical optical resolution, kinetic enzymatic resolution of racemic mixture or regioselective modification of the binaphthol scaffold the following article is presented.

Keywords: BINOL, atropoisomers, oxidative coupling, optical resolution, enantioselective synthesis, chiral ligands


Wiadomości Chemiczne, 2012, 66, 485.
Back   |  Home page

 


HYPERVALENT COMPOUNDS OF SULFUR, SELENIUM AND TELLURIUM.
PART 1. GENERAL CHARACTERISTICS

Adrian Zając

Zakład Chemii Heteroorganicznej, Centrum Badań Molekularnych i Makromolekularnych Polskiej Akademii Nauk, ul. Sienkiewicza 112, 90-363 Łódź
e-mail: adrian@cbmm.lodz.pl


The goal of this four-part review is a presentation of the results of recent studies on the properties and chemistry of hypervalent sulfur, selenium and tellurium compounds.

The term "hypervalency" has been known since 1969 when Musher used it to describe molecules bearing heteroatoms which formally did not fulfill the octet rule. This violation was explained by the postulate concerning the existence of a 3-center 4-electron bond between a hypervalent heteroatom and two axial electronegative ligands. The bond is the a combination of two ligand orbitals and a pz orbital of a central heteroatom which results in the formation of three molecular orbitals. The distances between the central atom and these two ligands are longer than the length of the typical sp2 bonds, such as equatorial ones. Moreover, the effective electron density is shifted from the central atom towards the axial ligands what results in the fulfillment of the octet rule of this atom. The geometry of this system is trigonal bipyramid (Fig. 2), except from compounds having three 3-center 4-electron (3c-4e) bonds which have tetragonal bipyramid geometry (Fig. 3). The term "geometry" includes positions of ligands and lone electron pairs. The stability of hypervalent compounds is affected by a few factors: electronegativity of ligands, formation of five-membered cyclic structures involving the central atom and the number of electron shells of the central atom. Martin proposed three-symbol notation N-X-L for these structures, which was further modified (Tab. 1). Hypervalent compounds can isomerize according to various mechanisms: Berry pseudorotation (Scheme 1), turnstile rotation (Scheme 2), cuneal inversion (Scheme 3), lever mechanism (Scheme 4), or Bailar twist (Scheme 5). Furthermore, hypervalent structures of 10-X-4 and 10-X-5 type with trigonal bipyramid geometry, C1 or C2 symmetry and at least three different ligands can exist as optically active species (Tab. 2, Fig. 5-7, Scheme 6), especially the "spiro" ones, which are resistant to isomerization. In 1977 Martin and Balthazor proposed extended Cahn-Ingold-Prelog convention for description of the absolute configuration of chiral hypervalent compounds (Fig. 5).

Keywords: hypervalency, 3c-4e bond, sulfurane, persulfurane, selenurane, perselenurane, tellurane, pertellurane, Berry pseudorotation, Martin sulfurane, trigonal bipyramid, tetragonal bipyramid, synthesis, chirality, optical activity, isomerization


Wiadomości Chemiczne, 2012, 66, 529.
Back   |  Home page

 


SELECTED COOLING COMPOUNDS USED IN COSMETICS

Michalina Adaszyńska, Maria Swarcewicz

Zakład Syntezy Organicznej i Technologii Leków, Wydział Technologii i Inżynierii Chemicznej, Zachodniopomorski Uniwersytet Technologiczny w Szczecinie, Al. Piastów 42, 71-065 Szczecin
e-mail: mswar@zut.edu.pl; michalina.adaszynska@gmail.com


Menthol and new cooling compounds are widely used to improve modern toothpastes, gums, breath fresheners, cosmetic lotions, deodorants, shaving gels, and shaving aid composites. This paper reviews the use of menthol and new classes of cooling agents, that have been discovered since the 1970s, in cosmetic preparations. We have presented here 57 chemical structures. In addition, we briefly touch upon cold receptors and mechanism of action. Finally, we add up, recent findings on the production of cooling ingredients in the world. The underlying process in thermoreception depends on ion transport across cellular membranes. Thermoreceptors belong to a class of transient receptor potential (TRP) channels. Among them are temperature-sensitive thermoreceptors TRPM8 or TRPA1. Certain types of chemical agonists activate the same thermoTRP channels, as for example menthol or icilin. Only the (-)-menthol enantiomer possesses clean, desirable minty odor and intense cooling properties (Fig. 1). Natural menthol is normally about 99.0% to 99.6% pure, with the remaining impurities being other constituents found in the cornmit oil. Synthetic (-)-menthol is normally about 99.8% pure and has less of the minty top note than the natural menthol. The other natural and synthetic compounds being menthol-related coolants are showed in Figure 3, as for example, menthone 1,2-glycerol ketal (17). From among 3-carboxamide-p-menthane derivatives as commercial cooling agents (Fig. 4), there are for example N-ethyl-p-menthane-3-carboxamide (25) as WS-3 and [ethyl 3-(p-menthane-3-carboxamido)acetate] as WS-5, which is currently the coldest of all commercial cooling agents (27). Other examples of recently discovered carboxamide coolants belong to a series of analogs of WS-23 (28). Of particular interest are various aryl p-menthane-3-carboxamides, such as N-benzo[1,3]dioxol-5-yl-3-p-menthanecarboxamide (36), which was reported to have 100 times more cooling intensity than menthol (Fig. 6). In 2010, Furrer disclosed a series of new p-menthane carboxamide and WS-23 analogs as cooling agents [56]. Three particularly potential cooling agents 50, 51 and 52 are shown in Figure 9.

Keywords: cooling ingredients, menthol, menthol-related, carboxamide, cosmetics


Wiadomości Chemiczne, 2012, 66, 543.
Back   |  Home page

 


BIOACTIVE COMPOUNDS IN WINE

Jan Małyszko*, Monika Karbarz

Uniwersytet Jana Kochanowskiego, Instytut Chemii, ul. Świętokrzyska 15, 25-408 Kielce
*e-mail: malyszko@ujk.edu.pl


Wines are the subject of an increasing number of investigations. The benefits of red wine became widely recognized after the observation of "French paradox" [8-10]. It has been found that there is a low mortality rate from ischemic heart disease among French people despite their high consumption of saturated fatty acids and the prevalence of other risk factors. The health-protective properties of wine are attributed to their antioxidant activity, i.e. the capability to scavenge reactive oxygen species, ROS. An imbalance between antioxidants and oxygen species results in oxidative stress leading to cellular damage. The phenolic compounds present in wine show beneficial physiological properties including protection against coronary heart disease, as well as anti-inflammatory and anti-carcinogenic activity. Most of the beneficial effects of wine are attributed to the presence of flavonoids, resveratrol, phenolic acids and other antioxidants. This paper reviews the significance of different compounds present in wine and their effect on human health.

Chapter 1 focuses on flavonoids: flavonols, flavan-3-ols and anthocyanidins (Fig. 1) [14-29]. This class of compounds can exist both in a simple form, as aglycones, and bounded with sugars, as glycosides. The presence of phenolic hydroxyl group in these compounds is essential for their antioxidant activity and enables to scavenge free radicals in vivo.

Chapter 2 describes chemical and physicochemical properties of resveratrol (Fig. 2) [30-41] which is the main antioxidant in wine. Moreover, this compound has been shown to inhibit the oxidation of low density lipoproteins and the aggregation of platelets [44-47]. Resveratrol also exhibits anti-inflammatory and anticancer properties [48, 49].

Chapter 3 reveals that wines are also a good source of other antioxidants [50-55] as phenolic acids (Fig. 3), tyrosol and hydroxytyrosol (Fig. 4), and also melatonin (Fig. 5).

Unfortunately, some wines can include mycotoxins, mainly ochratoxin A [59, 60] (Fig. 6), which is produced by the phytopatogenic fungi, Aspergillus carbonarius.

All types of red wine contain different amounts of ethanol and phenolic antioxidants, and therefore it is probable that the cardioprotective effect of red wine is caused by both these kinds of components [57-58]. Epidemiological observations, clinical and experimental in vitro research prove that regular and moderate intake of wine, particularly red wine, reduces cardiovascular morbidity and mortality [66-70].

Keywords: antioxidant activity, flavonoids, melatonin, phenolic acids, red wine, resveratrol,


Wiadomości Chemiczne, 2012, 66, 563.
Back   |  Home page

 


HYPERVALENT COMPOUNDS OF SULFUR, SELENIUM AND TELLURIUM. PART 2. SULFURANES 10-S-3 AND 10-S-4

Adrian Zając

Zakład Chemii Heteroorganicznej, Centrum Badań Molekularnych i Makromolekularnych Polskiej Akademii Nauk,
ul. Sienkiewicza 112, 90-363 Łódź
e-mail: adrian@cbmm.lodz.pl


The compounds presented herein are sulfuranes 10-S-3 and 10-S-4 containing hypervalent sulfur atom. They have been known for a relatively long time. Nevertheless, they, and especially 10-S-4 species, are still of great interest due to their unique properties. The review presents recent approaches to the synthesis of these compounds, their selected structural, physical, chemical, stereochemical and electronic properties and their use as reagents and catalysts in several reaction types. The presence of structures of these types as intermediates, which explains selected reaction mechanisms, will also be shown.

Keywords: hypervalency, 3c-4e bond, sulfurane 10-S-3, sulfurane 10-S-4, Berry pseudorotation, trigonal bipyramid, synthesis, chirality, optical activity, isomerization, ligand coupling, ligand exchange


Wiadomości Chemiczne, 2012, 66, 593.
Back   |  Home page

 


PEROXYNITRITE A STRONG BIOLOGICAL OXIDANT

Michał Bijak*, Michał Błażej Ponczek, Joanna Saluk, Marta Chabielska, Julita Stępniak, Paweł Nowak

Katedra Biochemii Ogólnej, Uniwersytet Łódzki, ul. Pomorska 141/143, 90-236 Łódź
*e-mail: mbijak@biol.uni.lodz.pl


As demonstrated in recent years, one of the major factors of oxidative stress, generated in the circulatory system, in both acute and chronic pathological conditions, is peroxynitrite (ONOO-) [4]. Peroxynitrite is a strong biological oxidant and nitrating compound, generated in vivo from a rapid reaction of two relatively less reactive, but commonly found, of free radicals: nitrogen monoxide (NO) and superoxide (O2-) [8]. This reaction occurs spontaneously and is not catalyzed by any enzyme. A fundamental reaction of ONOO- in biological systems is its fast reaction with carbon dioxide (k = 5,7 · 104 M-1 s-1) and yields a short-lived intermediate, nitrosoperoxycarbonate (ONOOCO2-), which homolyzes leads to the formation of carbonate (CO3-) and nitrogen dioxide (NO2) radicals (yield ~35%) [29, 30] (Fig. 1), which are one-electron oxidants. ONOO- is responsible for oxidative modifications in a wide variety of biomolecules and is capable to induce of nitrative changes in sulfur and aromatic amino acids, especially 3-nitrotyrosine and dityrosine formation [17] (Fig. 2). This article describes the formation, reactivity and biological action of peroxynitrite.

Keywords: peroxynitrite, oxidative stress, 3-nitrotyrosine


Wiadomości Chemiczne, 2012, 66, 623.
Back   |  Home page

 


CHEMICAL ASPECTS OF TARGETED ANTICANCER THERAPY. II. BOND OF CARRIER TO DRUG

Karolina M. Werengowska1, Marek Wiśniewski1, Artur P. Terzyk1*, Natalia Gurtowska2, Tomasz A. Drewa2, Joanna Olkowska2

1 Wydział Chemii Uniwersytetu Mikołaja Kopernika w Toruniu,Katedra Chemii Materiałów, Adsorpcji i Katalizy,
Zespół Fizykochemii Materiałów Węglowych,ul. Gagarina 7, 87-100 Toruń
2 Collegium Medicum im. Ludwika Rydygiera Uniwersytetu Mikołaja Kopernika w Bydgoszczy, Zakład Inżynierii Tkankowej,
ul. M. Karłowicza 24, 85-092 Bydgoszcz
*e-mail: aterzyk@chem.uni.torun.pl


Traditional anticancer therapy is usually low effective. Popular and common drugs applied in anticancer therapy are characterized by low solubility and nonspecific biodistribution in an organism. The chemotherapy kills not only cancer but also healthy cells [4]. Building of modern drug delivery systems based on nanocarriers is a new method of anticancer treatment. The present study is directed towards nanomaterials (as carbon nanotubes, liposomes, polymeric micelles) as modern drug carriers. Thus, we characterized mechanisms of actions of traditional chemotherapeutics: paclitaxel, cisplatin and doxorubicin (Figs. 3-5) [1, 15, 21]. The purpose of this study is a description of the bioconjugation of drug-nanocarrier. Chemotherapeutics can be connected to external or internal surfaces of nanocarriers (Fig. 6) [6]. We described two main methods of drug delivery from internal space of nanocarriers: nanoextraction and nanocondensation (Fig. 7) [32]. The type of drug-carrier bonding can be covalent or noncovalent. We report recent advances in the field showing the formation of esters (Figs. 10-11) [28, 29, 53, 54], acethyl-hydrazone (Fig. 12) [55-61], amides [62-64], and disulfides groups [12, 65]. These reactions depend on functional groups in structures of drugs and require suitable modification of nanocarrier surfaces. In practice, the functionalization of nanocarrier surface is associated with the covering with polymers including PEG, HPMA, PG and PLGA [3]. Adsorption is the most popular process of bonding chemotherapeutic and nanomaterials (Fig. 13) [66]. Special attention is paid to electrostatic interaction between drugs: paclitaxel [74], cisplatin [59, 76, 77], doxorubicin [67-73] and nanocarriers: carbon nanotubes and/or polymeric micells. By application of modern anticancer therapy, drugs are preserved from lysosomal degradation and to fast reaction in biological environment. Finally, nanocarriers improve adsorption of drug and increase concentration of drug only in cancer tissues [6, 7].

Keywords: drug nanocarriers, anticancer drugs, covalent bonds, adsorption


Wiadomości Chemiczne, 2012, 66, 637.
Back   |  Home page

 


THE ROUTE AGAINST THE SUN. EARLY HISTORY OF VITAMIN D

Jerzy Wicha

Instytut Chemii Organicznej Polskiej Akademii Nauk,ul. Kasprzaka 44/52, 01-224 Warszawa
e-mail: jerzy.wicha@icho.edu.pl


Two natural products are called "vitamin D": (1) vitamin D3 which is biosynthesized in humans and animals and (2) vitamin D2 which is generated in photochemical rearangement of a sterol of fungy - ergosterol (Fig. 1 and 2). The vitamins D are further metabolized (Scheme 1) first into 25-hydroxy- and then into 1α,25-dihydroxy derivatives in various tissues. The compounds control the calcium transport and act as a cell growth regulator important for tumor prevention.

The early history of vitamin D stems from outburst of rickets at the beginning of the industrialization era. Rickets was a child bond disease that often led to a permanent disability. A comprehensive description of the rickets was presented by D. Whistler (1619-1684) and then F. Glisson (1597-1677) and coauthors. Jędrzej Śniadecki (1768-1838) was the first who associated the rickets with the sunlight. In his book "On the Physical Education of Children" Śniadecki stated that exposition of a child's body to a direct action of sunlight is the most efficient method for the prevention and the cure of rickets (Illustrations 1 and 2). T. A. Palm in 1890 observed that the rickets is rare in countries where sunshine is abundant and prevalent whenever there is a little of sunlight. The first experimental evidence on the sunlight effects in rickets were presented by J. Raczyński in 1912 who postulated that the sunlight affects metabolic processes in blood related to calcium transport (Illustration 3 and 4). E. Mellanby showed (1919) that the disease is connected to the lack of certain dietary factors and he recommended the use of cod liver - oil. K. Huldschinsky experimentally proved that UV irradiation cures the rickets. The Mellanby's and Huldschinsky's observations were confirmed by clinical studies in 1922.

E.V. McCollum has developed efficient methods for "biological analysis" of food and named anti-rachitic factor as vitamin D.H. Steenbock and A.F. Hess in 1924 found independently that various food products gain anti-rachitic properties after being irradiated with a UV lamp. A.F. Hees and A. Windaus showed that irradiation of ergosterol affords a product with high anti-rachitic activity.

In 1919 the first structure for cholesterol has been proposed by A. Windaus (Scheme 2, Fig. 3) and then with contribution of H. Wieland it was modified to the "Wieland-Windaus" structure (1928, Nobel Price lectures, Fig. 4). O. Diels' investigation on dehydratation of cholesterol (Fig. 5) and J.D. Bernal's crystallographic measurements of ergosterol challenged the Wieland-Windaus structure. Finally, the correct structure for cholic acid and sterols was deduced by O. Rosenheim and H. King (Fig. 6).

In 1932 crystalline vitamin D2 was prepared in the Windaus laboratory (Scheme 3). In 1935 vitamin D3 was isolated from a fish-oil and the same compound was synthesized from cholesterol (Illustration 5). The structure of vitamin D2 was elucidated by Windaus in 1935 (Illustration 6) and confirmed by X-ray studies in 1948. Scientific contributions of Adolf Windaus are associated with his highest ethical standards and non-conformist political position in the national-socialist age.

Keywords: history, vitamin D, biosynthesis vs. nutrition, sterols, structural investigations, ultraviolet light, anti-rachitic diet


Wiadomości Chemiczne, 2012, 66, 671.
Back   |  Home page

 


INORGANIC NANOPARTICLES IN NUCLEAR MEDICINE

Agata Kasperek, Aleksander Bilewicz

Instytut Chemii i Techniki Jądrowej, Centrum Radiochemii i Chemii Jądrowej ul. Dorodna 16, 03-195 Warszawa
e-mail: a.kasperek@ichtj.waw.pl


Rapid and widespread growth in the use of nuclear medicine for both diagnosis and therapy of disease has been the driving force for a design of novel radiopharmaceuticals. Particularly, recent progress in nanotechnology gives the possibility of designing new carriers for delivering radionuclides in a manner to overcome some limitation such as nonspecific biodistribution and targeting, water insolubility, poor oral bioavailability and others. There are several perspective therapeutic and diagnostic radionuclides which cannot be bound to biomolecule via chemical bonds. Nanocarriers gives the opportunity for binding such radionuclides.

Nanoparticles have to be designed with an optimal size (above 100 nm) and surface characteristic to easily penetrate the barriers in the body and prevent elimination by reticuloendothelial system. Among nanoparticles which are used for delivery and targeting are polymers, lipids, viruses, organometallic compounds, precious metals or metal oxides.

This article presents a brief review of the applications, advantages, difficulties and future perspective of inorganic nanoparticles, which can be used as radionuclide delivery systems. The main direction of developing new nanostructures for nuclear medicine is to create multimodal agents which are suitable for such combined methods as PET/MRI or PET/NIRF. Also combination of diagnostic and therapeutic agents in one nanocontainer is possible.

Keywords: nanoparticle, nuclear medicine, drug delivery system, drug carriers,


Wiadomości Chemiczne, 2012, 66, 697.
Back   |  Home page

 


MAYA BLUE, ONE OF THE MOST IMPORTANT ACHIEVEMENTS OF MESOAMERICA

Małgorzata Łukarska, Anna Zywert, Stanisław Kowalak

Uniwersytet im. A. Mickiewicza w Poznaniu, Wydział Chemii, ul. Grunwaldzka 6, 60-780 Poznań
e-mail: skowalak@amu.edu.pl


The Maya Blue is a famous blue pigment developed by pre-Columbian civilizations of Mesoamerica and manufactured there for about thousand years. It was applied for body decoration, important for cruel religious rituals, as well as for artistic paintings, murals, or coloration of ceramics. Its production was abandoned in XVII century and the procedure forgotten. The chemical nature of this blue pigment remained a puzzle for a long time and only in nineteen sixties it was revealed [1, 2] that it is a composite consisting of inorganic matrix (palygorskite) that accommodates molecules of organic dye - indigo. The preparation procedure was rediscovered [3] and the products analogous to classical Maya Blue could be obtained by simple thermal insertion of indigo into palygorskite (and also into sepiolite). However, the nature of chemical interaction between dye and matrix that provides very high resistibility of resulting pigments remains still not satisfactorily explained. The hydrogen bonds or coordinative interaction with matrix cations are taken into an account. Zeolites and other molecular sieves can be efficiently applied as matrices for pigments similar to Maya Blue. The coloration and other properties of pigments can be considerably changed by initial modification of zeolites with various cations, what supports an important role of complexes formed by dye molecules and zeolite cations. On the other hand, the zeolite-like materials AlPO4 as well as to some extent mesoporous silica (with some contribution of micropores) lacking any cations are also efficient matrices for pigments analogous to Maya Blue. Not only indigo, but also indigo derivatives (leucoindigo, thioindigo, indigo carmine) could be embedded inside the molecular sieves. The thermal insertion as well as crystallization of zeolites from gels supplemented with respective dye can be used for pigment synthesis. It is interesting that role of matrix can be also played by representative of novel MOF family of the molecular sieves.

Keywords: Maya Blue, pigments, zeolites, indigo, encapsualtion


Wiadomości Chemiczne, 2012, 66, 715.
Back   |  Home page

 


LIBRARIES OF CHEMICAL COMPOUNDS

Krzysztof M. Zwoliński, Zbigniew J. Leśnikowski

Pracownia Wirusologii Molekularnej i Chemii Biologicznej, Instytut Biologii Medycznej PAN, ul. Lodowa 106, 93-232 Łódź
e-mail: kzwolinski@cbm.pan.pl, zlesnikowski@cbm.pan.pl


Over the past decade one can observe a scientific revolution taking place resulting in an explosion of new biotechnologies. Moreover, with the end of the human genome project and following expansion of the extensive genetic research an unprecedented number of new biological targets useful in drug design have been identified. Simultaneously, new methods such as combinatorial synthesis have expanded the overall size of chemical libraries and high-throughtput technologies have enabled to screen more than one million compounds a day [43]. However, an increasing size of chemical libraries in a random fashion may not necessary increase a probability of success and the overall number of successfully identified leads. Thus, success of any drug discovery program depend heavily on the assumed selection criteria of appropriate molecules [58] which properties should maximize the chances of identifying ligands for any given target. Selection criteria used for compounds to generate diverse as well as focused chemical libraries are briefly discussed in the present overview. We describe the most important quality factors such as size, diversity and chemical tractability which should be always kept in mind during the design of chemical libraries.

Chemical space is enormous and limited only by a chemist`s imagination. The number of possible drug-like molecules within chemical space has been estimated to be around 1060 [17]. In contrast the overall number of atoms in the observable Universe is approximately 1080. It is obvious that it is impossible to synthesize every possible molecule so one need to explore only those regions of chemical space which are enriched with molecules of appropriate structure and function. Recent strategies for the design of high-quality collections of structurally diverse sets of small molecules are discussed in the context of probing the chemical space in order to find new biologically active structures.

Keywords: chemical libraries, virtual libraries, chemical space, drug, natural products


Wiadomości Chemiczne, 2012, 66, 741.
Back   |  Home page

 


AVOGADRO PROJECT (IAC) AND REDEFINITION OF THE MOLE

W. T. Chyla

Applied Science Enterprise, P. O. Box 22, 00-975 Warszawa 12
e-mail: chylawt@wp.pl


The paper presents the International Avogadro Coordination (IAC) and the problem of redefinition of the unit of amount of substance (the mole) in the context of a comprehensive reform of the international system of units (SI) that is expected to conclude in a few years. The redefinition program, known as the New SI or the Quantum SI, draws on Maxwell's concept of replacing artifact standards with atomic standards, which are considered stable and available - at least in principle - to everybody, everywhere and at any time; the idea has been generalized and the present tendency is to define base units in terms of physical constants. Redefinition of the mole is a spin-off project associated with redefinition of the kilogram; two high-purity, 28Si-enriched silicon spheres were manufactured to make possible very accurate measurements of their parameters in order to determine ("count") the number of silicon atoms in each of the two spheres. Initially, the project has been designed to determine the Avogadro constant, with the intent to redefine the kilogram as the mass of an exactly specified number of atoms. Once the consensus had been reached that the kilogram should be defined by fixing the numerical value of the Planck constant and the unit of mass should be realized with the use of the watt balance, the Avogadro project of silicon spheres was reinterpreted and became the basis for the redefinition and realization of the mole. In this paper, I discuss the origins of the Avogadro project (IAC), the physical principle of a very accurate measurement of the Avogadro constant and technical details of the realization of that project. The problem of resolving the discrepancy between results of the IAC and the watt balance project is reviewed. The current status of the IAC is discussed and difficulties with the proposed wording of the New SI redefinition of the mole are indicated. It is expected that all the technical problems can be resolved before the next meeting of the CGPM, where voting on implementation of the New SI is expected.

Keywords: Chemical metrology, amount of substance, redefinition of the mole, Avogadro project, International Avogadro Coordination, IAC, New SI, Quantum SI, AF-SI


Wiadomości Chemiczne, 2012, 66, 767.
Back   |  Home page

 


OKRUCHY. XXVI. O "Układzie Okresowym" Primo Levi'ego

Ignacy Z. Siemion

Wydział Chemii Uniwersytetu Wrocławskiego, ul. F.Joliot-Curie 14, 50-383 Wrocław



Wiadomości Chemiczne, 2012, 66, 789.
Back   |  Home page

 


BIOLOGICAL ACTIVITY OF 2-AMINO-1H-BENZIMIDAZOLE DERIVATIVES. PART I

Wanda Paulina Nawrocka, Anna Nowicka, Hanna Liszkiewicz

Katedra i Zakład Technologii Leków, Uniwersytet Medyczny im Piastów Śląskich we Wrocławiu, pl. Nankiera 1, 50-140 Wrocław
e-mail: anna.nowicka@am.wroc.pl


The main goal of this article is to present a various biological activity of 2-aminobenzimidazole derivatives. During the past 20 years the biological activity of 2-aminobenzimidazole have been studied.

2-Aminobenzimidazole occurs in a broad spectrum of drugs and pharmacological agents with anticancer [21], antibacterial [14], antiviral [10], analgesic or antiaggregatory properties.

There are 30 drugs, 2-aminobenzimidazole derivatives, registered in the world. Mebendazole represents a big group of antiparasitic drugs [25]. Antihistaminic II-nd generation drug with selective activity towards H1 receptors represents Astemizol [2]. Antiviral drugs are: Enviroksym and its isomer Zinviroksym and Enviraden [3-5]. Synthesized 2-aminobenzimidazole derivatives are active against HCV [7], HIV [8, 9] or HCHV [11].

Selected compounds exhibit antiviral [3-5], antifungal [22-24] and antiparasitic [26-28] activity. Some of them can be used in the treatment of bacterial infections [12-14]. Many of 2-aminobenzimidazole analogues are histamine H1, H2, H3 and also H4 receptor antagonists [30, 33, 35, 39].

Keywords: 2-aminobenzimidazole derivatives, biological activity


Wiadomości Chemiczne, 2012, 66, 811.
Back   |  Home page

 


BIOLOGICAL ACTIVITY OF 2-AMINO-1H-BENZIMIDAZOLE DERIVATIVES. PART II

Wanda Paulina Nawrocka, Anna Nowicka, Hanna Liszkiewicz

Katedra i Zakład Technologii Leków, Uniwersytet Medyczny im Piastów Śląskich we Wrocławiu, pl. Nankiera 1, 50-140 Wrocław
e-mail: anna.nowicka@am.wroc.pl


2-Aminobenzimidazole occur in a broad spectrum of drugs and pharmacological agents with hypotensive [26], antihistaminic, immunotropic [16], antiarrhythmic [25], analgesic [21, 22] or antiaggregatory properties [27].

There are 30 drugs, 2-aminobenzimidazole derivatives, registered in the world which exhibit diverse pharmacological activities. Carbendazim is an antifungal drug, but in 2003 it has been registered as anticancer [1]. They are also voltage sensitive calcium channel blockers [33], inhibitors of vascular endothelial growth factor [12].

The main goal of this article is to present a various biological activity of 2-aminobenzimidazole derivatives. During the past 20 years the biological activity of 2-aminobenzimidazole have been studied.

Based on a review of the chemical literature, derivatives of 2-aminobenzimidazole showed a multipharmacological effects such as hypotensive effect [28], anti-inflammatory effect [20] or antibacterial activity. Some chemical compounds, which contain in their structure 2-aminobenzimidazole system inhibit neurodegeneration and in the future they may be used in a treatment of Alzheimer's disease or Parkinson's disease [32]. Some of described derivatives of 2-aminobenimidazole can be used in a treatment of metabolic syndrome and diabetes [38].

Synthesis of new 2-aminobenzimidazole derivatives with anticancer activity is now one of the most important direction of research conducted on this group of compounds.

Present compounds exhibit anticancer, antiproliferate, neuroprotetic and antiinflaminatory activity. Some of them can be used in a treatment of diabetes and hypertension.

Keywords: 2-aminobenzimidazole derivatives, biological activity


Wiadomości Chemiczne, 2012, 66, 839.
Back   |  Home page

 


STUDIES ON THE STRUCTURE AND DYNAMICS OF N-TERMINAL SEQUENCES OF DERMORPHIN AND THEIR ANALOGS BY MEANS OF SOLID STATE NMR SPECTROSCOPY AND XRD

Katarzyna Trzeciak-Karlikowska

Samodzielna Pracownia Badań Strukturalnych, Centrum Badań Molekularnych i Makromolekularnych Polskiej Akademii Nauk, ul. Sienkiewicza 112, 90-363 Łódź
e-mail: ktrzecik@cbmm.lodz.pl


Deltorphin I (Tyr-D-Ala-Phe-Asp-Val-Val-Gly-NH2) and dermorphin (Tyr-D-Ala-Phe--Gly-Tyr-Pro-Ser-NH2) are natural opioid peptides that have been isolated from the skin of South American frogs [1]. The presence of D-amino acid is crucial for their biological activity. The synthetic analogs of given heptapeptides containing L-alanine are not analgesics [2]. Analysis of the influence of stereochemistry on molecular packing, dynamics and biological functions of neuropeptides is still important for receptor studies and practical applications (e.g. design of new selective pain killers).

Presented research is focused on the structure and dynamics of two N-terminal sequences of dermorphin: tripeptide Tyr-D-Ala-Phe 1, tetrapeptide Tyr-D-Ala-Phe-Gly 2, and their analogs with L-alanine: Tyr-Ala-Phe 3 and Tyr-Ala-Phe-Gly 4, using solid state NMR and X-ray diffraction. This study clearly demonstrates that 1 and 2 crystallized under different conditions to form exclusively one structure [3, 4]. In contrast, tripeptide and tetrapeptide with L-Ala in the sequence very easily form different crystal modifications. Tyr-Ala-Phe 3 crystallizes into two forms: 3a and 3b [5], while Tyr-Ala-Phe-Gly 4 gives three modifications: 4a, 4b and 4c [4]. It seems that one of the factors, which can be important in the preorganization mechanism anticipating the formation of crystals, is the intramolecular CH-π interaction between aromatic rings of tyrosine and/or phenylalanine and the methyl group of alanine. Such interaction is possible only for D-Ala residue. For L-Ala in the peptide sequence, the methyl group is aligned on the opposite side with respect at least to one of the aromatic groups. It can be further speculated that such internal CH-π contacts can also occur during the interaction of ligand-receptor, making the message sequence of opioid peptides more rigid and finally selective. By employing different NMR experiments (e.g. PISEMA MAS and PILGRIM) it was proven that the main skeleton of analyzed peptides is rigid, whereas significant differences in the molecular motion of the aromatic residues were observed [4, 6]. Solid state 2H NMR spectroscopy of samples with deuterium labeled aromatic rings: Tyrd4-D-Ala-Phe 5, Tyr-D-Ala-Phed5 6, Tyrd4-Ala-Phe 7, Tyr-Ala-Phed5 8 was used to analyze the geometry and time scale of the molecular motion. At ambient temperature, the tyrosine ring of sample 5 is rigid and in the sample 6 the phenylalanine ring undergoes a "π-flip". The tyrosine rings of form I of 7 and 8 are static, while the phenylalanine rings of form II of 7 and 8 undergo a fast regime exchange [6]. Variable temperature 2H measurements proved that the tyrosine and phenylalanine rings of two forms of compounds 7 and 8 became more mobile with increasing temperature. In contrast, the aromatic rings of samples 5 and 6 preserve their dynamics regime (static tyrosine and "π-flip" phenylalanine) in a large range of temperatures [6].

The analysis of 13C, 15N labeled tetrapeptide Tyr-D-Ala-Phe-Gly 2'-phospholipid membrane interactions suggests that peptide 2' is aligned on the surface of the membrane (RFDR MAS) and the sandwich-like π-CH3-π arrangement of the pharmacophore is preserved (DARR) [7].

Keywords: opioid peptides, CH-π interactions, molecular dynamics, peptide-phospholipid interaction, NMR spectroscopy, 1H Ultra Fast MAS NMR, PISEMA MAS, PILGRIM, XRD


Wiadomości Chemiczne, 2012, 66, 867.
Back   |  Home page

 


HYPERVALENT COMPOUNDS OF SULFUR, SELENIUM AND TELLURIUM. PART 3. MARTIN SULFURANE, SULFURANES 10-S-5 AND 12-S-6

Adrian Zając

Zakład Chemii Heteroorganicznej, Centrum Badań Molekularnych i Makromolekularnych Polskiej Akademii Nauk, ul. Sienkiewicza 112, 90-363 Łódź
e-mail: adrian@cbmm.lodz.pl


In this part of the review one of the most famous 10-S-4 sulfurane called Martin sulfurane together with sulfuranes 10-S-5 and persulfuranes 12-S-6 will be presented.

Martin sulfurane has been well known for a relatively long time but it is still useful in organic synthesis as a dehydrating, coupling and oxidizing agent. Its use in selected substitution reactions will be also described.

Next, synthesis and selected properties of sulfuranes 10-S-5, mainly sulfurane oxides, and persulfuranes 12-S-6, will be shown. Besides synthetic methods, the review is focused on the investigations of the stability and isomerization of these types of compounds, which is particularly interesting for persulfuranes, because of the presence of three 3c-4e bonds.

Keywords: hypervalency, 3c-4e bond, sulfurane, persulfurane, Martin sulfurane, trigonal bipyramid, tetragonal bipyramid, synthesis, chirality, optical activity, isomerization, ligand coupling


Wiadomości Chemiczne, 2012, 66, 893.
Back   |  Home page

 


BIOMATERIALS FOR TISSUE ENGINEERING AND REGENERATIVE MEDICINE

Maria Nowacka

Centrum Badań Molekularnych i Makromolekularnych Polskiej Akademii Nauk, ul. Sienkiewicza 112 , 90-363 Łódź, Polska
e-mail: mnowacka@cbmm.lodz.pl


Tissue engineering is a very rapidly developing domain of science. There is a huge interest in the biology of stem cells, especially in their proliferation, differentiation and spreading in the response to different factors. Biomaterials with properties similar to the natural environment of human body (accelerating wounds healing and not causing immunological response) as well as these that can control cells behavior are in constant need. This review presents the most popular polymeric biomaterials for tissue engineering and regenerative medicine [3-5, 8-20], explains interactions between cells and biomaterials [3, 13, 22-33], describes the most important surface properties that can have an influence on cells i.e. topography [36, 43-47, 53-72], roughness [1, 5, 31, 51, 66, 73-84], stiffness [54, 84-102], hydrophobicity, chemistry [4, 11, 16, 20, 27, 31, 32, 36-38, 42, 58, 103-112] and surface charge [18, 37, 113-116].

Keywords: biomaterials, biopolymers, surface specificity, tissue engineering


Wiadomości Chemiczne, 2012, 66, 909.
Back   |  Home page

 


METHODS FOR THE SYNTHESIS OF ORGANIC DERIVATIVES CONTAINING THE TRIPLE BOND CARBON-CARBON

Irena Bylińska, Katarzyna Guzow

Uniwersytet Gdański, Wydział Chemii, ul. J. Sobieskiego 18/19, 80-952 Gdańsk
e-mail: irma@chem.univ.gda.pl


Compounds containing triple bonds are lately in the centre of interest of many research groups. This is mainly connected with their usefulness as substrates to obtain complex compounds with various applications in different areas of science, industry and medicine [1-5]. Because of that many researchers are interested in methods of synthesis of such compounds. As the demand for derivatives with triple bonds is quite big and the one universal method of synthesis does not exist, the new ones are developed or these already known are improved. To enable choosing the best method for synthesis of acetylene derivatives, this review is presented. The oldest methods based on elimination reaction are mentioned [6-9], whereas those enabling incorporation of acetylene unit into more complicated compounds are described more thoroughly [10-92]. The latter methods based on homo- or heterocoupling lead to symmetrical [10-25] and unsymmetrical acetylene and bisacetylene derivatives [26-92]. The most popular reactions such as Glaser reaction (Scheme 1) [10-12], Cadiot-Chodkiewicz reaction (Schemes 11 and 12) [26-49], Hay reaction (Scheme 13) [13, 14] as well as Sonogashira-Hagihara reaction [50-69] and their modifications (Tab. 3) [57] are described. Moreover, the influence of main parameters such as type of substrate used, ratio of reagents, catalyst, base, solvent, reaction time and temperature on the reaction yield is presented (Tabs 1-4) [14, 18, 23, 25, 50-58, 69-78].

Keywords: triple bond, acetylene, synthesis, homocoupling, heterocoupling, Glaser reaction, Hay reaction, Cadiot-Chodkiewicz reaction, Sonogashira-Hagihara reaction


Wiadomości Chemiczne, 2012, 66, 935.
Back   |  Home page

 


DERIVATIVES OF 1,2,3-TRIAZOLE. POTENTIAL DRUGS?

Emilia Bankowska*, Andrzej E. Wróblewski

Zakład Chemii Bioorganicznej, Wydział Farmaceutyczny, Uniwersytet Medyczny w Łodzi, ul. Muszyńskiego 1, 90-151 Łódź
*e-mail: emilia.bankowska@gmail.com


Recently, 1,2,3-triazoles have gained an increased attention in the field of drug discovery because several derivatives have already been marketed as medications (e.g. tazobactam, cefatrizine, rufinamide) [1, 2] and many of them appeared to be very active in diverse biological studies including plinambulin 69 currently in the last stage of the clinical trials [60].

In this review very recent investigations of antibacterial, antitubercular, antifungal, antipsychotic, antiepileptic, anti-inflammatory, hypoglycemic, anticancer and antiviral properties of 1,2,3-triazole derivatives are discussed. These studies allowed to select several compounds which were found to be more active in comparison to the already used drugs.

Keywords: 1,2,3-triazole derivatives, antibacterial activity, antifungal activity, antitubercular activity, antipsychotic activity, anticonvulsant activity, anti-inflammatory activity, hypoglycemic activity, anticancer activity, antiviral activity


Wiadomości Chemiczne, 2012, 66, 993.
Back   |  Home page

 


BIOLOGICAL SYNTHESIS OF METAL NANOPARTICLES

Irena Maliszewska

Zakład Chemii Medycznej i Mikrobiologii, Wydział Chemiczny Politechniki Wrocławskiej, ul. Wybrzeże Wyspiańskiego 27, 50-370 Wrocław
e-mail: irena.helena.maliszewska@pwr.wroc.pl


Nanotechnology has attracted a great interest in recent years due to its expected impact on many areas such as energy, medicine, electronics and space industries. One of the most important aspects in researching nanotechnology is a synthesis of metal nanoparticles of well-defined sizes, shapes and controlled monodispersity. One of the exciting methods is the production of metal nanostructures using biological systems such as microbes, yeast, fungi and several plant extracts. Biological systems provide many examples of specifically modified nanostructured molecules. Perhaps, the best known are the magnetotactic bacteria which intracellularly synthesize magnetic nanocrystals in magnetosomes. The production of many other metal and metal alloy nanoparticles by organisms is a consequence of detoxification pathways. Organisms have evolved specific mechanisms to prevent excessive accumulation of metals. There are two probable ways to capture or trap the metal ions, electrostatic interaction and/or secretion of substances that will adhere the ions. For the process of intracellular synthesis of nanoparticles, the ions are involved in a nutrient exchange and/or substance diffusion. Thereafter, the functional reducing agents (i.e. reducing sugars, fatty acids, glutathione, flavonoids, terpenoids, fitochelatines etc.) and/or enzymes (NAD+/NADP+- dependent reductases, hydrogenases, oxidases), convert the harmful ions into non-harmful matters. Finally, the nuclei grow and subsequently intracellularly or extracellularly accumulate to form nanoparticles. Despite numerous research made in this area, the mechanism of biosynthesis is not a fully understood. In this paper an overview of the use of living organisms in the biosynthesis of metal nanoparticles is given and different mechanisms leading to the formation of nanoparticles are demonstrated.

Keywords: metal nanoparticles, quantum dots, biosynthesis, bacteria, yeasts, fungi plants


Wiadomości Chemiczne, 2012, 66, 1023.
Back   |  Home page

 


ISOXAZOLIDINE ANALOGUES OF NUCLEOSIDES

Kamil Kokosza*, Dorota G. Piotrowska

Zakład Chemii Bioorganicznej, Wydział Farmaceutyczny, Uniwersytet Medyczny w Łodzi, ul. Muszyńskiego 1, 90-151 Łódź
*e-mail: k.kokosza@wp.pl


Compounds having isoxazolidine moiety are of special interest since they show a broad spectrum of biological activity, including anticancer [1-5], antiviral [6], antibacterial [7-9] and antifungal activities [9-12]. Extensive studies on isoxazolidine moiety containing compounds resulted in discovery of several potentially antiviral and anticancer drugs (e.g. pyridemine-A 1 [2, 3], as well as isoxazolidines substituted with thymine and 5-fluorouracil 52a (AdT) [38-40] and 59 [(-)-AdFU] [41-43], respectively). In this review the most spectacular examples of the synthesis of isoxazolidine analogues of nucleosides are discussed and their biological activity is emphasized.

Keywords: 1,3-dipolar cycloaddition, nitrones, isoxazolidines, nucleoside analogues, nucleobases, C-nucleosides, homonucleosides, nucleosides, phosphonylated nucleosides, psico-nucleosides, antiviral activity, anticancer activity.


Wiadomości Chemiczne, 2012, 66, 1041.
Back   |  Home page

 


SYNTHESIS, STRUCTURES AND BIOLOGICAL ACTIVITY OF IMIDAZO[4,5-b]PYRIDINE DERIVATIVES. PART 1

Hanna Liszkiewicz, Anna Nowicka, Wanda Paulina Nawrocka

Katedra i Zakład Technologii Leków, Uniwersytet Medyczny im Piastów Śląskich we Wrocławiu, pl. Nankiera 1, 50-140 Wrocław
e-mail: anna.nowicka@am.wroc.pl


This review presents most of the literature data about imidazo[4,5-b]pyridine derivatives and their biological activity. The main goal of this paper is to present various methods for the preparation of imidazo[4,5-b]pyridine analogues. There are some drugs, imidazo[4,5-b]pyridine derivatives, registered in the world, which exhibit diverse pharmacological activities. Noberastine [4] represent antihistaminic II generation drug with selective activity to H1 receptors. Tenatoprazole [5] is a novel proton pump inhibitor with a prolonged plasma half-life which possesses antiulcer activity. Sulmazole [3] is a new cardiotonic agent, an A1 adenosine receptor antagonist.

Based on the review of the chemical literature, derivatives of imidazole[4,5-b]pyridine showed a multipharmacological effects. Presented compounds exhibit anticancer [14, 17, 19], antidepressant [44, 45], cardiotonic, anticoagulant [37] activities. Some of them can be used in the treatment of heart diseases [3]. There were also described derivatives of imidazo[4,5-b]pyridine with the potential use in the treatment of diabetes [48], hypertension and hyperlipidemia. Some chemical compounds which contain in their structure the imidazo[4,5-b]pyridine system inhibit neurodegeneration [34, 38] and can be used in the treatment of neurodegenerative disorders eg. Parkinson's disease, Alzheimer's disease or multiple sclerosis. In addition, some of the imidazo[4,5-b]pyridine possess antivirial [40-42], antimicrobial and cytotoxic activities.

Keywords: imidazo[4,5-b]pyridine derivatives, biological activity, synthesis, structures


Wiadomości Chemiczne, 2012, 66, 1071.
Back   |  Home page

 


THE PROTEOLYTIC MACHINERY AND ITS REGULATORS

Julia Stój, Przemysław Karpowicz

Katedra Chemii Medycznej, Wydział Chemii, Uniwersytet Gdański, ul. Sobieskiego 18, 80-952 Gdańsk
e-mail: jstoj@wp.pl, przemek@chem.univ.gda.pl


One of the proteolytic pathways existing in a cell is ubiquitin- proteasome system (UPS). This highly organized and ATP-dependent system is based on the multifunctional enzyme - the proteasome. Ubiquitin in this pathway plays a role of a tag which marks proteins intended for destruction.

Ubiquitylated proteins are recognized and degraded by the 26S proteasome. It consists of a cylindrical-shaped proteolytic core - the proteasome 20S, and attached to it regulatory particles 19S (Fig. 2). The core is composed of four rings, each of them formed by seven subunits. The inner β-rings harbour active sites (in Eukaryota two of each kind: chymotrypsin-like (ChT-L), trypsin-like (T-L) and peptidylglutamyl (PGPH)). The outer, α-rings create a gated channel leading to the catalytic chamber [8]. In a latent proteasome the gate is closed by tightly packed N-terminal residues of ? subunits (Fig. 4). Due to such architecture the active sites of the proteasome are not freely available for the substrates. An opening of the gate in physiological conditions occurs after binding the activators such as 11S, 19S or PA200.

By catalysing degradation of proteins, the UPS is deeply involved in regulation of cellular physiology. It is also involved in removing of misfolded or damaged proteins and supports the immune system by generating antigenic peptides. Defects in functioning of this proteolytic system play a causal role in the development of a number of diseases, including inflammation, neurodegenerative diseases and various cancers [2-6] what is the reason why the proteasome has become an important therapeutic target.

Detailed information about the structure, catalytic activities and mechanisms of functioning of the different proteasome complexes existing in cells is essential to understand their role in organisms as well as to develop new compounds which may find pharmaceutical application.

Keywords: proteasome, ubiquitin-proteasome system, inhibitors, allostery


Wiadomości Chemiczne, 2012, 66, 1097.
Back   |  Home page

 


HYPERVALENT COMPOUNDS OF SULFUR, SELENIUM AND TELLURIUM. PART 4. SELENURANES AND TELLURANES

Adrian Zając

Zakład Chemii Heteroorganicznej, Centrum Badań Molekularnych i Makromolekularnych Polskiej Akademii Nauk, ul. Sienkiewicza 112, 90-363 Łódź
e-mail: adrian@cbmm.lodz.pl


In this part selenuranes (10-Se-4 and 10-Se-5) and perselenuranes 12-Se-6 as well as telluranes 10-Te-4 and pertelluranes 12-Te-6 will be presented. The main goal is to describe recent reports on the synthesis, chemical, physical, spectral and conformational behavior, stereochemistry, stability and biological activity of these compounds. Their occurrence as reaction intermediates will also be shown.

Keywords: hypervalency, 3c-4e bond, selenurane, perselenurane, tellurane, pertellurane, trigonal bipyramid, tetragonal bipyramid, synthesis, chirality, optical activity, isomerization, cuneal inversion


Wiadomości Chemiczne, 2012, 66, 1119.
Back   |  Home page

 


T. Cukierda,   Last changes: