Synthesis, Molecular Structure, and Solution-Dependent Behavior of Nickel Complexes Chelating Anilido-Imine Donors and Their Catalytic Activity toward Olefin Polymerization
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- 作者：Haiyang Gao ; Wenjuan Guo ; Feng Bao ; Guoqiu Gui ; Junkai Zhang ; Fangming Zhu ; and Qing Wu
- 刊名：Organometallics
- 出版年：2004
- 出版时间：December 20, 2004
- 年：2004
- 卷：23
- 期：26
- 页码：6273 - 6280
- 全文大小：194K
- 年卷期：v.23,no.26(December 20, 2004)
- ISSN：1520-6041
文摘
A series of novel nickel complexes (1-4) bearing anilido-imine ligands, [(Ar1N=CHC6H4NAr2)NiBr]2 (Ar1 = Ar2 = 2,6-dimethylphenyl, 1; Ar1 = 2,6-dimethylphenyl, Ar2 = 2,6-diisopropylphenyl, 2; Ar1 = Ar2 = 2,6-diisopropylphenyl, 3; Ar1 = 2,6-diisopropylphenyl, Ar2= 2,6-dimethylphenyl, 4), have been synthesized and characterized. The solid-state structuresof the complexes 1, 2, and 4 were confirmed by X-ray single-crystal analyses to be in theform of a dinuclear and bromine-bridged structure. However, there is an equilibrium thatshifts between the monomer and dimer in solution, which has been monitored using 1HNMR and UV-vis spectrophotometry. The themodynamic parameters for the equilibriumswere calculated to be 
H = +13.68 kJ/mol and S = 40.32 J/(mol K) for 1 and H = +8.35kJ/mol and S = 15.21 J/(mol K) for 3. All nickel complexes show low activities for ethyleneoligomerization with MAO as cocatalyst but high catalytic activities for norbornenepolymerization in the presence of MAO.
H = +13.68 kJ/mol and S = 40.32 J/(mol K) for 1 and H = +8.35kJ/mol and S = 15.21 J/(mol K) for 3. All nickel complexes show low activities for ethyleneoligomerization with MAO as cocatalyst but high catalytic activities for norbornenepolymerization in the presence of MAO.