ELECTROCHEMICAL STUDIES OF AN OXIDATIVELY INDUCED RING SLIPPAGE IN 17-ELECTRON (ETA-3-INDENYL)(ETA-5-INDENYL)V(CO)2

Oxidation of (η5-arene)2V (arene = indenyl, C5H5, C5Me5) with [(C5H5)2Fe][PF6] under a carbon monoxide atmosphere provides a convenient route to [(η5-arene)2V(CO)2]+ complexes. The cyclic voltammogram of the indenyl compound shows two reversible one-electron reduction waves. Reduction of 18-electron [(η5-indenyl)2V(CO)2][PF6 ] leads directly to the 17-electron (η3-indenyl)(η5-indenyl)V-(CO)2 . A lower limit for the η3-to-η5 ring slip rate constant is estimated to be 10/sec at -32°C. Reductions of the cationic C5H5 and C5Me5 analogues were irreversible and showed no evidence for ring slipped intermediates. © 1990.