Spectroscopic and electrochemical study of trinuclear ferracyclopentadienyl clusters [Fe3(.mu.-CO)2(CO)6(RC2R)2]

The redox chemistry of triiron metallacyclopentadienyl clusters Fe3(C0)8(RC2R)h2a s been investigated by electrochemical and spectroscopic techniques. Their ‘H and 13CNMR resonances have been assigned by comparison of the NMR data of different isomers and by two-dimensional and selective decoupling experiments. The sequence of electrode processes has been postulated on the basis of the response of cyclic voltammetry (CV), coulometry, electron spin resonance (ESR) spectroscopy, and chemical tests. The influence of the metallacyclopentadienyl ring substituents on the trend of the redox potentials supports the high electronic delocalization in the Fe3C4 skeleton previously postulated on the basis of theoretical calculations. Finally, an effective electron transfer catalyzed (ETC) synthesis of the two [Fe3(C0)7P- (OMe)3(PhC2Ph)zi]s omers has been achieved.