Structural diversity of bimetallic rhodium and iridium half sandwich dithiolato complexes

The synthesis of a range of rhodium(III) and iridium(III) half sandwich complexes with aryl dithiolato ligands of varying geometry and flexibility is reported. These include dinuclear [Cp*M(S‒R‒S)]2 complexes 3b and 4b, M = Rh, Ir; S‒R‒S = naphthalene-1,8-dithiolate (b) and four dinuclear complexes bearing bridging dithiolate ligands [(Cp*M)2(μ2-Cl)(μ2-S‒R‒S)]Cl 3c, 4c, 5b, 6b, M = Rh, Ir; S‒R‒S = naphthalene-1,8-dithiolate (b) or acenaphthene-5,6-dithiolate (c). The introduction of a less rigid biphenyl dithiolate backbone resulted in the tetranuclear dicationic complex [(Cp*Rh)4(S-R-S)3]Cl2 (3d), S‒R‒S = biphenyl-2,2’-dithiolate (d) with dithiolate ligands in two different bridging modes. All new complexes were fully characterised by multinuclear NMR, IR, Raman and MS spectroscopy and single crystal X-ray diffraction.