Chemistry of [{Cr(cp)(CO)3}2], (cp =η5-C5H5). Reaction with elemental P4. A high yield synthesis and crystal structures of [{Cr(cp)(CO)2}2(µ-η2-P2)] and [Cr(cp)(CO)2(η3-P3)]

Abstract

The reaction of [{Cr(cp)(CO)₃}₂](cp =η⁵-C₅H₅) with 1 molar equivalent of P₄ in toluene at 90 °C gave [{Cr(cp)(CO)₂}₂(P₂)] and [Cr(cp)(CO)₂(P₃)](2) in 53 and 40% yields, respectively. A radical mechanism has been postulated. Single-crystal X-ray diffraction studies show that (1) contains a µ-η²-P₂ group bridging two metal-metal bonded Cr atoms and (2) contains a tricyclo-η³-P₃ ligand. Crystal data: (1) monoclinic, space group P2₁/n, a= 7.934(2), b= 17.189(3), c= 11.327(2), β= 97.69(2)°, and Z= 4; (2) monoclinic, space group P2₁/_c, a= 11.398(3), b= 14.383(1), c= 13.323(4), β= 115.32(2)°, and Z= 8. The synthetic method, structures, and spectral features of these complexes are compared with those of analogous complexes of other transition metals, particularly Mo.