Metal-Assisted Opening of Intact P Tetrahedra.

The reactivity of ruthenium and manganese complexes bearing intact white phosphorus in the coordination sphere was investigated towards the low-valent transition-metal species [Cp'''Co] (Cp'''=η -C H -1,2,4-tBu ) and [L M] (L =CH[CHN(2,6-Me C H )] ; M=Fe, Co). Remarkably, and irrespective of the metal species, the reaction proceeds by the selective cleavage of two P-P edges and the formation of a square-planar cyclo-P ligand. The reaction products [{CpRu(PPh ) }{CoCp'''}(μ,η -P )][CF SO ] (5), [{Cp Mn(CO) } {CoCp'''}(μ,η -P )] (6) and [{Cp Mn(CO) } {ML }(μ,η -P )] (Cp =C (C H nBu) ; L =CH[CHN(2,6-Me C H )] ; M=Fe (7 a), Co (7 b)), respectively, were fully characterized by single-crystal X-ray diffraction and spectroscopic methods. The electronic structure of the cyclo-P ligand in the complexes 5-7 is best described as a π-delocalized P system, which is further stabilized by two and three metal moieties, respectively. DFT calculations envisaged a potential intermediate in the reaction to form 5, in which a quasi-butterfly-shaped P moiety bridges the two metals and behaves as an η -coordinated ligand towards the cobalt center.