New biimidazole and bibenzimidazole derivatives: mono and binuclear palladium(II) or platinum(II) complexes and heterobinuclear palladium(II)-rhodium(I) or platinum(II)-rhodium(I) complexes

Abstract

Novel neutral biimidazolate or bibenzimidazolate palladium(II) and platinum(II) complexes of the type M(NN) 2(dpe) [M = Pd, Pt; (NN) 2 2− = BiIm 2−, BiBzIm 2−. dpe = 1,2- bis(diphenylphosphino) ethane] have been obtained by reacting MCl 2(dpe) with TI 2(NN) 2. Complexes M(NN) 2(dpe) which are Lewis bases react with HClO 4 or [M(dpe)(Me 2CO) 2](ClO 4) 2 to yield, respectively, mononuclear cationic complexes of general formula [M{H 2(NN) 2](dpe) (M = Pd, Pt; H 2(NN) 2 = H 2BiIm, H 2BiBzIm) and homobinuclear palladium(II) or platinum(II) cationic complexes of the type [M 2{μ - (NN) 2}(dpe) 2](ClO 4) 2. Reactions of M(BiBzIm)(dpe) with [Rh(COD) (Me 2CO) X](ClO 4) render similar heterobinuclear palladium(II)-rhodium(I) and platinum(II)-rhodium(I) cationic complexes, of general formula [(dpe)M(μ-BiBzIm)Rh(COD)](ClO 4) (M = Pd, Pt; COD = 1,5-cyclooctadiene). Di- and mono-carbonyl derivatives [(dpe)M(μ-BiBzIm)Rh(CO)L](ClO 4) (M = Pd, Pt; L = CO, PPh 3) have also been prepared. The structures of the resulting complexes have been elucidated by conductance studies and IR spectroscopy.