Synthesis and electrochemistry of Co(III) and Co(I) complexes having C5Me5 auxiliary

The synthesis and electrochemistry of half-sandwich type of Co(III) complexes [(C5Me5)Co(bidentate)(CH3CN)](BF4)2 {bidentate = dppe (1,2-bis(diphenylphosphino)ethane), dppp (1,3-bis(diphenylphosphino)propane), bpy (2,2′-bipyridine), en (ethylenediamine)) are reported. Cyclic voltammograms of [(C5Me5)Co(bidentate)(CH3CN)](BF4)2 in CH3CN s showed two redox couples assignable to Co(II)/Co(III) and Co(I)/Co(II). The Co(I) complex having C5Me5 and dppe was also prepared. Two redox couples of this Co(I) complex, (C5Me5)Co(dppe), in CH3CN coincided with those of [(C5Me5)Co(dppe)(CH3CN)](BF4)2 in spite of the structural change around the metal center.