Bimetallic nickel complexes with bridging dithiolato Schiff base ligands: synthesis, mass spectral characterisation and electrochemistry

Abstract

Schiff base dithiols with thiophene or phenyl linkers were prepared from condensation of the dialdehydes 2,5-(OHC) 2C 4H 2S, 1,3-(OHC) 2C 6H 4, 1,4-(OHC) 2C 6H 4 and 1,4′-(OHC) 2(C 6H 4) 2 with 4-H 2NC 6H 4(SH). The Schiff base dithiols readily reacted with Ni(η 5-C 5H 5)(PR 3)Br (R=Bu or Ph) in the presence of Et 3N to form bimetallic complexes (η 5-C 5H 5)(PR 3)NiSC 6H 4NC(H)ArC(H)NC 6H 4SNi(PR 3)(η 5-C 5H 5) (Ar=C 4H 2S ( 6), 1,3-C 6H 4 ( 7), 1,4-C 6H 4 ( 8), 1,4′-(C 6H 4) 2 ( 9). The bimetallic nature was established from elemental analysis and mass spectrometry. Cyclic voltammetry of complexes 6, 8 and 9 are indicative of electronic communication between the nickel centres via the bridging dithiolato Schiff base ligands.