New unsymmetrical thioether- and thiolate-substituted ferrocenediyl ligands and their metal complexes

Abstract

A series of new unsymmetrical 1,1′-disubstituted ferrocenediyl ligands featuring thioether or thiolate substituents have been conveniently synthesised. The chelating nature of the ligands is shown by coordination with a range of transition metal centres and bridged metal dimeric species are observed with platinum and palladium. Electrochemical studies show that the diferrocene species is a partially delocalised Robin–Day Class II system, whilst on coordination of metal centres to the monoferrocene ligands, the oxidation potential of the ferrocene subunit is greatly increased ranging from 0.25 to 0.60 V upon passing from platinum(II) to palladium(II) ions. Interestingly, the outer ferrocenediyl subunits of the dimeric complexes indicate electronic interaction through the diplatinum or dipalladium backbones. The chromium- and vanadium-containing species act as low activity, pre-catalysts for ethylene polymerisation.