Dimeric rhodium(III), iridium(III) and ruthenium(II) thiosalicylate complexes

Abstract

Reactions of the chloride-bridged dimers [LMCl(μ-Cl)]₂ (M=Rh, Ir; L=Cp*=η⁵-C₅Me₅; M=Ru, L=η⁶-p-cymene) with two mole equivalents of thiosalicylic acid (HSC₆H₄CO₂H, H₂tsal) and excess base gives the dimeric rhodium(III), iridium(III) and ruthenium(II) thiosalicylate complexes [LM(tsal)]₂. Reaction of the complex [Cp*RhCl₂(PPh₂)] with one equivalent of H₂tsal and triethylamine in dichloromethane gives a mixture of the dimer [Cp*Rh(tsal)]₂ and the phosphine complex [Cp*Rh(tsal)(PPh₃)]; upon recrystallisation, pure dimer is obtained. A single-crystal X-ray diffraction study on the rhodium and ruthenium dimers reveals the expected thiolate-bridged M₂(μ-S)₂ unit. Electrospray mass spectrometry (ESMS) is a useful technique in studying the chemistry of the thiosalicylate complexes, all complexes giving strong [M+H]⁺ ions. With added thiosalicylic acid, cations of the type [(LM)₂(Htsal)₃]⁺ were detected in the mass spectra.