Wydział Chemii

Karolina Zdyb

Maxym O. Plutenko

Rostyslav D. Lampeka

Matti Haukka

Małgorzata Ostrowska

Igor O. Fritsky

Elżbieta Gumienna-Kontecka

2017

Polyhedron

137

60-71

10.1016/j.poly.2017.07.009

Naukowa

Angielski

Artykuł

Five new mononuclear complexes formed by the polynucleating ligand 2-[1-(3,5-dimethyl)pyrazolyl]-2-hydroxyimino-N′-[1-(2-pyridyl)ethylidene]acetohydrazide (HL): [Ni(L)(HL)]ClO₄·2CH₃OH (1), [Ni(L)₂]·CH₃OH (2), [Zn(L)(HL)]ClO₄·2CH₃OH (3), [Zn(L)₂]·CH₃OH (4) and [Cu(L)₂]·CH₃OH (5) were synthesized and characterized by elemental analysis, mass-spectrometry, IR-spectroscopy and X-ray analysis. The complexes reveal distorted octahedral N₄O₂ coordination arrangement formed by both protonated and deprotonated (1, 3) or two deprotonated ligand molecules (2, 4, 5). The presence of non-coordinated oxime and pyrazole groups resulted in the formation of extensive systems of hydrogen bonds in the crystal packing of 1–5. Potentiometric titrations, ESI-MS and spectrophotometric studies of complex formation in MeOH/H₂O solutions indicated the presence of mono- and polynuclear complexes with Cu(II), Ni(II) and Zn(II) ions. The solution studies carried out for an excess of Cu(II) over HL ligand (2:1 and 3:2 M ratio) indicated also the formation of polynuclear Cu₃L₂H_x species, with an involvement of additional nitrogen donors in copper coordination. In binuclear complex [Cu₂(L)₂(DMF)₂](ClO₄)₂·DMF(6) obtained in solid state, the Cu(II) coordination, analogous to the one in 1–5, was supported by pyrazole N atom.

coordination compounds, Cu(II), Ni(II), Zn(II) complexes, Schiff base ligands, Solution studies, Solid state data

https://doi.org/10.1016/j.poly.2017.07.009

http://www.elsevier.com