An uncommon bonding mode of a familiar ligand: a molybdenum complex with afour-electron donor chelating eta(3)-PPh3 ligand, and its structural determination using synchrotron radiation

A crystallographic study using synchrotron radiation shows that a C=C bond of one phenyl group of a PPh3 ligand bonds to Mo in [Cp(CO)(2)(PPh3)Mo](+), resulting in an unusual bonding mode in which PPh3 functions as a chelatin g four-electron donor ligand.