823196-40-3Relevant academic research and scientific papers
Synthesis, molecular structure, and solution-dependent behavior of nickel complexes chelating anilido-imine donors and their catalytic activity toward olefin polymerization
Gao, Haiyang,Guo, Wenjuan,Bao, Feng,Gui, Guoqiu,Zhang, Junkai,Zhu, Fangming,Wu, Qing
, p. 6273 - 6280 (2004)
A series of novel nickel complexes (1-4) bearing anilido-imine ligands, [(Ar1N=CHC6H4-NAr2)NiBr] 2 (Ar1 = Ar2 = 2,6-dimethylphenyl, 1; Ar 1 = 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 structures of the complexes 1, 2, and 4 were confirmed by X-ray single-crystal analyses to be in the form of a dinuclear and bromine-bridged structure. However, there is an equilibrium that shifts between the monomer and dimer in solution, which has been monitored using 1H NMR and UV-vis spectrophotometry. The themodynamic parameters for the equilibriums were calculated to be ΔH = +13.68 kJ/mol and ΔS = 40.32 J/(mol K) for 1 and ΔH = +8.35 kJ/mol and ΔS = 15.21 J/(mol K) for 3. All nickel complexes show low activities for ethylene oligomerization with MAO as cocatalyst but high catalytic activities for norbornene polymerization in the presence of MAO.
