[CP''CO(P-4)((CP''CO)(2)(MU-CO))] (CP''=ETA(5)-C(5)H(3)TBU(2)) - A COMPLEX WITH A P-4 UNIT ON THE WAY TO A P-1 AND A P-3 LIGAND

The title compound is obtained from the reaction of [Cp '' Co(CO)(2)] (Cp '' = eta(5)-C(5)H(3)tBu(2) with P-4 in THF under UV radiation and is structurally characterized by X-ray diffraction, In [Cp '' Co(P-4){ (Cp '' Co)(2)(mu-CO)}], a planar P-4 ligand is eta(4)-capped by a Cp ' ' Co unit and a [(Cp '' Co)(2) mu-CO)] dimer coordinates to only three P atoms from below, resulting in a kite-like distortion of the P-4 mo lecule with two short and two long P-P distances. The longer distances could be considered to be on the borderline between a bonding P-P len gth and the van der Waals contact. The factors controlling the structu re have been studied by EHT calculations.