Reactions of coordinated ligands II. Metal(0) carbonyl complexes with diphosphanes R(X)PP(X)R (R  aryl; X  Br, I, H, C 4H 9) as bridging ligands

Abstract

Complexes (CO) 5MR(X)PP(X)RM(CO) 5 (R  aryl; X  Br, I; M  Cr, W) (II) have been prepared by reaction of (CO) 5M·THF with the corresponding diphosphanes RXPPXR. The disproportionation, R(X)PP(X)R [rlhar2]; (RP) n + RPX 2, which is observed in solutions of the free diphosphanes, does not take place with the coordinated ligands. This is also the case for the diphosphane in (CO) 5CRC 6H 5(H)PP(H)C 6H 5Cr(CO) 5, which is obtained from IIa by reduction with LiAlH 4. these are additional examples of stabilization of oligophosphanes by complexs formation. The complex (CO) 5CrC 6H 5(C 4H 9PP(C 4H 9)C 6H 5Cr(CO) 5 has been synthesized from IIa and BuLi. The IR, NMR and mass spectra of the complexes are discussed.