Abstract

The synthesis and properties of new cationic iron(II) complexes of general formula [?5-C5H5)FeL(?2-dppa)]A [A = I-, L = CO(1); A = BF4, L = CO(2) CH3CN(4), ?1-dppa(5); dppa = NH(PPh2)2] are described. The carbonyl complex [(?5-C5H5)Fe(CO) (?2-dppa)]BF4 is deprotonated to give the neutral complex [(?5-C5H5)Fe(CO){?2- (PPh2)2N}](3). All complexes have been characterized by elemental analysis and IR and NMR spectroscopies. Cyclic voltammetry of complexes 1-5 shows a diverse redox chemistry in acetonitrile solution. While the reduction of 1 and 2 leads to the formation of a dinuclear Fe(I) complex, 4 and 5 form mononuclear species of Fe(I); oxidation of metal centers of 1 and 2 is not observed and in complexes 3 and 4 the metal centers are oxidized at potentials < 1. Complex 5 in acetonitrile solution is transformed into complex 4.