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)₂C₄H₂S, 1,3-(OHC)₂C₆H₄, 1,4-(OHC)₂C₆H₄ and 1,4'-(OHC)₂(C₆H₄)₂ with 4-H₂NC₆H₄(SH). The Schiff base dithiols readily reacted with Ni( ⁵-C₅H₅)(PR₃)Br (R=Bu or Ph) in the presence of Et₃N to form bimetallic complexes ( ⁵-C₅H₅)(PR₃)Ni&unknown;SC₆H₄N&unknown;C(H)ArC(H)&unknown;NC₆H₄S&unknown;Ni(PR₃)( ⁵-C₅H₅) (Ar=C₄H₂S (6), 1,3-C₆H₄ (7), 1,4-C₆H₄ (8), 1,4'-(C₆H₄)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.