ANODICALLY-INDUCED METAL DEPROTONATION OF THE HYDRIDE COMPLEXES [(PCH2CH2PPH2)(3))M(H)CL] (M=FE, RU, OS) - THE FIRST STEP TO THE ELECTROGENERATION OF FE(I), RU(I) AND OS(I) 5-COORDINATE COMPLEXES

The electrochemical behaviour of the (hydride)chloride complexes [(PP3 )M(H)Cl] (M = Fe, Ru, Os) has been studied by cyclic voltammetry and c ontrolled-potential electrolysis in tetrahydrofuran (PP3 = P(CH2CH2PPh 2)(3)). All compounds undergo anodically-induced deprotonation to give the corresponding M(II) chlorides [(PP3)MCl](+). All the oxidation pr ocesses correspond to an EEC reaction pathway. The two-electron oxidat ion processes occur at coincident potentials for M = Ru, at slightly d ifferent potentials for M = Os, and at largely different potentials fo r M = Fe. The M(II) complexes [(PP3)MCl](+) are reversibly reduced to the corresponding M(I) derivatives [(PP3)MCl], which can be generated in solution by exhaustive macroelectrolysis. The paramagnetic Fe(I), R u(I) and Os(I) chloride complexes have been characterised by X-band ES R spectroscopy in glassy and fluid solutions.