Repozytorium
Wyszukaj
Kolekcje
Inne
A family of group 4 metal alkoxo complexes with an M3(μ3-O) core relevant to Ziegler-Natta catalyst intermediates.
Autorzy
Rok wydania
2003
Czasopismo
Numer woluminu
9
Strony
181-190
DOI
10.1002/chem.200390011
Kolekcja
Język
Angielski
Typ publikacji
Artykuł
Highly optimized syntheses of interesting model intermediates in Ziegler–Natta catalysis are described. These zirconium and hafnium alkoxo complexes have a stable (μ3-O)M3 core and incorporate an alkaline earth metal containing moiety, as illustrated. Their formation pathway gives an insight into the mechanism of Z–N procatalyst formation. Solvent polarity plays a pivotal role in formation of the final product. Reactions of [Mg(thffo)2] (1) or [Ca(thffo)2] (2) with ZrCl4 or HfCl4 in a CH2Cl2/THF/CH3CN mixture give thermall stable neutral heterobimetallic tetranuclear complexes [M3M′(μx-O)(μ,η2-thffo)6(Cl)6] (thffo=tetrahydrofurfuroxide; M/M′/x: 3, Zr/Mg/3; 4, Hf/Mg/3; 5, Zr/Ca/4; 6, Hf/Ca/4) as colorless crystals in 75–82 % yield. X-ray diffraction studies show complexes 3–5 to contain oxo-bridged M3 triangles that are capped by an alkaline earth metal-containing moiety to form species of C3 symmetry. Reactions of ZrCl4 and HfCl4 with pure tetrahydrofurfuryl alcohol in EtOH and MeOH provide ionic complexes [M3(μ3-O)(μ,η2-thffo)3(L)3(Cl)6]Cl (M/L: 8, Zr/EtOH; 9, Hf/EtOH; 10, Zr/MeOH) in 66–79 % yield. Complexes 8–10 consist of M3 triangles that are analogous to those in 3–6 and possess similar overall symmetry, as shown by X-ray crystallography. Changes in the reaction conditions afforded the asymmetric neutral dimer [Zr2(μ-thffo)2(thffoH)(Cl)6] (7) and the homometallic [Zr3(μ3-O)(μ,η2-thp)3(thf)2(Cl)7] (11).
Adres publiczny
https://doi.org/10.1002/chem.200390011
Strona internetowa wydawcy
Podobne publikacje
Syntheses and molecular structures of [Mg4(THFFO)6(OSiPh3)2] and [Al3Mg(μ3-O)(THFFO)3(Me)6] relevant to Ziegler-Natta catalyst intermediates (THFFO = 2-tetrahydrofurfuroxide).
Sobota Piotr, Utko Józef, Ejfler Jolanta, Jerzykiewicz Lucjan B.
Elementary steps of Ziegler-Natta catalyst intermediates formation. Incorporation of magnesium alkoxides with [Ti(dipp)4], Ph3SiOH, [Al.(CH3)3], and MCl(3)4 (M=V, Zr).
Szafert Sławomir, Utko Józef, Ejfler Jolanta, Jerzykiewicz Lucjan B., Sobota Piotr
An extremely rare example of asymmetric tetranuclear core {M4(μ3-X)2(μ-X)4} in a novel alkoxo-bridged heterometallic Cr/Cd complex.
Semenaka V. V., Nesterova Oksana V., Kokozay Vladimir N., Dyakonenko Viktoriya V., Shishkin Oleg V., Boča Roman, Jezierska Julia