Preparation and spectroscopic characterization of some heterobimetallic complexes of 1,1-dicarboethoxy-2,2-ethylene dithiolate involving divalent and monovalent metal ions

Abstract

Reaction of the anionic dithiolato complexes [M′(DED) 2] 2− (M′ = Cd II or Pd II; DED = 1,1-dicarboethoxy-2,2-ethylene dithiolate) with metal ions occurs forming a new series of heterobimetallic complexes M[M′(DED) 2] (M = CO II, Ni II, Cu II, Pb II, 2Ag I or 2Tl I). The precursor ions [M′(DED) 2] 2− used for the synthesis of heterobimetallic complexes have been isolated as (Et 4N) 2[M′(DED) 2] salts for the first time. The composition of the complexes has been determined by elemental analysis. The tendency for the anionic dithiolato complexes, [M′(DED) 2] 2−, to act as a bridging moiety via the sulphur atoms to form heterobimetallic complexes has been explored. Heterobimetallic compounds are non-conducting, while (Et 4N) 2[M′(DED) 2] salts exhibit 2 : 1 electrolytic behaviour in nitrobenzene. The IR spectra indicate dinegative bidentate behaviour of DED with the presence of non-equivalent ester groups, while 1H and 13C NMR spectral studies suggest that the non-equivalent nature of the ester groups is not retained in solution. Magnetic moment and electronic spectral studies suggest a square-planar environment around cobalt(II), nickel(II), palladium(II) and copper(II).