Electron delocalization in molecule-bridged polymetallic systems. Unique neutral complexes of TCNE or TCNQ and up to four organometallic fragments (C5R5)(CO)2Mn

Electron transfer between the π-accepting TCNE or TCNQ (TCNX) ligands and π-electron-rich organometallic species (C 5 R 5 )(CO) 2 Mn(THF) (R=H, CH 3 ) results in the formation of polynuclear complexe [(C 5 R 5 )(CO) 2 Mn]n(η n -TCNX) until full coordinative saturation is achieved at the nitrile groups (n=4). Infrared spectroscopy points to the net transfer of one π electron to the TCNX acceptor ligand and indicates a highly symmetrical and strongly coupled situation for the tetranuclear complexes