Synthesis and structural analysis of niobium(V) complexes containing amine triphenolate ligands of the type, [NbCl(X)(O-2,4-R2C6H2-6-CH2)31N] (R = Me, tBu, X = Cl, CF3SO3), and their use in catalysis for ethylene polymerization

Niobium(V) dichloride complexes containing amine triphenolate ligands, [NbCl2{(O-2,4-R2C6H2-6-CH2)(3)N}] [R = Me (1), Bu-t (2)], and their mono triflate analog, [NbCl(CF3SO3)(O-2,4-R2C6H2-6-CH2)(3) N] [R = Me (4), Bu-t (5)] have been prepared, and structures of complexes 1 and 5 have been determined by X ray crystallography; these complexes fold a distorted octahedral geometry around Nb. Complexes 1 and 2 exhibited catalytic activities for ethylene polymerization in the presence of MAO, and the activity markedly increased at high temperature (100, 120 degrees C); 2 showed the higher activities than 1 (activity by 2 in n-octane at 100 degrees C: 576 kg-PE/mol-Nb.h). (C) 2016 Elsevier Ltd. All rights reserved.