Structures of Novel Nickel(II)Complexes Bearing 2,6-Disubstituted Phenylisocyanides and Their Catalytic Activity towards Ethylene Polymerization

摘要

Novel Ni(II)complexes bearing 2-substituted or 2,6-disubsutituted aryl isocyanide ligands,NiBr_2[CN(2-Ar-C_6H_4)]_2 or NiBr_2[CN(2,6-Ar2-C_6H_3)]_2,were synthesized and subjected to studies on ethylene polymerization.In the cases where the Ar group is phenyl,the 2-substituted complex showed high catalytic activity to produce polyethylene with low molecular weight,whereas the 2,6-disubstituted analogue exhibited moderate activity to form high molecular weight polymer.Although introduction at 4'-substituent to the Ar group did not affect the catalytic activity,attachment of methyl groups to ortho-positions on the Ar group dramatically inhibited the reaction.