Bimetallic nickel complexes of macrocyclic tetraiminodiphenols and their ethylene polymerization

Abstract

Schiff’s base condensation of 2,6-diformyl-4-R-phenol and 4 , 4 ″ - diamino - 3 , 3 ″ , 5 , 5 ″ - R 4 ′ - o - terphenyl affords 34-membered macrocyclic tetraiminodiphenol compounds, o - C 6 H 4 { ( R 2 ′ C 6 H 2 ) – N CH – [ RC 6 H 2 ( OH ) ] – HC N ( R 2 ′ C 6 H 2 ) } 2 ( o - C 6 H 4 ) (R = H and R′ = iPr, 1; R = Me and R′ = iPr, 2; R = F and R′ = iPr, 3; R = Me and R′ = Et, 4; R = F and R′ = Et, 5) in good yields (47–62%), from which dinuclear nickel complexes, o - C 6 H 4 { [ ( R 2 ′ C 6 H 2 ) – N CH – ( RC 6 H 2 - O ) – HC N ( R 2 ′ C 6 H 2 ) - κ 2 - N , O ] Ni ( η 1 - CH 2 Ph ) ( PMe 3 ) } 2 ( o - C 6 H 4 ) (R = H and R′ = iPr, 6; R = Me and R′ = iPr, 7; R = F and R′ = iPr, 8) are prepared. Molecular structures of 2, dipotassium salt of 1, and 7 were confirmed by X-ray crystallography. Addition of B(C 6F 5) 3 to a toluene solution of 6– 8 gives insoluble precipitates which show good activity for ethylene polymerization.