Vanadium(<scp>iii</scp>) phenoxyimine complexes for ethylene or ε-caprolactone polymerization: mononuclear versus binuclear pre-catalysts
作者:Lucy Clowes、Mark Walton、Carl Redshaw、Yimin Chao、Alex Walton、Pertti Elo、Victor Sumerin、David L. Hughes
DOI:10.1039/c2cy20571h
日期:——
The mononuclear [C6H4NCH(ArO)]2VCl(THF)} (Ar = 2,4-t-Bu2C6H2 (1), Ar = C6H4 (2)), O[C6H4NCH(ArO)]2}VCl(THF) (Ar = 2,4-t-Bu2C6H2 (3), Ar = C6H4 (4)) and the binuclear vanadium(III) complexes [C6H4NCH(ArO)]VCl2(THF)2}2(μ-CH2CH2) (Ar = 2,4-t-Bu2C6H2 (5), Ar = C6H4 (6)), have been synthesized and fully characterized. The compounds [C6H5NCH(ArO)]VCl2(THF)2 (Ar = 2,4-t-Bu2C6H2 (7), Ar = C6H4 (8)), [2,4,6-Me3âC6H2NCH(ArO)]VCl2 (Ar = 2,4-t-Bu2C6H2 (9), Ar = C6H4 (10)) and [2,6-i-Pr2-C6H3NCH(ArO)]VCl2(THF)2 (Ar = 2,4-t-Bu2C6H2 (11), Ar = C6H4 (12)), μ-CH2CH2[NCH(C6H4O)]2VCl(THF)} (14) and C6H4[NCH(C6H4O)]2VCl(THF)} (15) were synthesized for comparative polymerization studies. The dizwitterionic compound [2,6-i-Pr2-C6H3N+(H)CH(C6H4O)]2VCl2O (13) was also isolated, and presumably formed via a fortuitous hydrolysis reaction. The complexes 2, 5 and 13 have been structurally characterized; the molecular structure of the parent ligand (L5) in 5 is also reported. All complexes have been screened for ethylene as well as ε-caprolactone polymerization, and results are compared against those for known related mono- and bi-nuclear counterparts to evaluate for possible cooperative effects. The compounds 10 and 12 have been supported on modified SiO2, analysed by XPS and subjected to homo-polymerization (ethylene) and co-polymerization (1-hexene and ethylene) studies.
合成并全面表征了单核化合物[C6H4NCH(ArO)]2VCl(THF)} (Ar = 2,4-t-Bu2C6H2 (1),Ar = C6H4 (2))和O[C6H4NCH(ArO)]2}VCl(THF) (Ar = 2,4-t-Bu2C6H2 (3),Ar = C6H4 (4)),以及双核钒(III)络合物[C6H4NCH(ArO)]VCl2(THF)2}2(μ-CH2CH2) (Ar = 2,4-t-Bu2C6H2 (5),Ar = C6H4 (6))。合成了化合物[C6H5NCH(ArO)]VCl2(THF)2 (Ar = 2,4-t-Bu2C6H2 (7),Ar = C6H4 (8))、[2,4,6-Me3–C6H2NCH(ArO)]VCl2 (Ar = 2,4-t-Bu2C6H2 (9),Ar = C6H4 (10))和[2,6-i-Pr2-C6H3NCH(ArO)]VCl2(THF)2 (Ar = 2,4-t-Bu2C6H2 (11),Ar = C6H4 (12)),μ-CH2CH2[NCH(C6H4O)]2VCl(THF)} (14)和C6H4[NCH(C6H4O)]2VCl(THF)} (15),以进行比较聚合研究。二盐型化合物[2,6-i-Pr2-C6H3N+(H)CH(C6H4O)]2VCl2O (13)也被分离出来,推测是在一次偶然的水解反应中形成的。化合物2、5和13已被结构表征;化合物5中母体配体(L5)的分子结构也被报告。所有络合物均已检测乙烯和ε-己内酯聚合的能力,并将结果与已知相关的单核和双核对照进行比较,以评估可能的协同效应。化合物10和12被支持在改性SiO2上,通过XPS分析,并进行了均聚合(乙烯)和共聚合(1-己烯与乙烯)研究。