Synthesis, Characterization And Catalysis Of Substituted Indenyl Nickel Complexes

A series of indenyl nickel complexes [(1-R-Ind)Ni(PPh3)X, R=C2H5, PhCH2, C5H9; X=C1, Br]have been prepared and characterized for the first time. Their catalytic activities for styrene and methyl methacrylate were also investigated.1. (l-C2H5-Ind)Ni(PPh3)X(X=Cl, Br) was synthesized by the reaction of l-C2H5-IndLi with Ni(PPh3)2Cl2 in the 1:1.8 molar ratio in ether at 0. Their structure were characterized by elemental analyses, 1H-NMR spectroscopy and single-crystal X-ray analysis.2. (1-PhCH2-Ind)Ni(PPh3)Cl was synthesized by the reaction of 1-PhCH2-IndLi with Ni(PPh3)2Cl2 in 1:1.8 molar ratio in ether at 0 and characterized by elemental analyses, 1H-NMR spectroscopy and single-crystal X-ray analysis.3. (l-C5H9-Ind)Ni(PPh3)Cl was synthesized by the reaction of l-C5H9-IndLi with Ni(PPh3)2Cl2 in the 1:1.8 molar ratio in DME at 0 and characterized by elemental analyses, 1H-NMR spectroscopy and single-crystal X-ray analysis.4. The catalytic behaviors of (l-R-Ind)Ni(PPh3)X (R=C2H5, PhCH2, C5H9; X=C1) in the styrene polymerization was tested. The results indicated that these nickel complexes were active catalysts in the presence of NaBPlu and PPh3. Among them, (1-C2H5-Ind)Ni(PPh3)Cl/NaBPh4/PPh3 showed the highest catalytic activity. When (l-C2H5-Ind)Ni(PPh3)Cl/PPh3/NaBPh4 is 1:4:7, the polymer yield can reach to 100% after 48 h of polymerization, and the polydisperity is fairly narrow.5. The catalytic activities of (l-R-Ind)Ni(PPh3)Cl (R=C2H5, PhCH2, C5H9) in the presence of CCl3Br for styrene or methyl methacrylate polymerization were tested. The preliminary results indicated that the polymerization of styrene or methyl methacrylate initiated by (l-R-Ind)Ni(PPh3)Cl/CCl3Br in toluene possesses some characteristics of atom transfer radical polymerization.