REDISTRIBUTION REACTIONS OF HYDROSILANES MEDIATED BY THE UNSYMMETRICAL AND HOMOMETALLIC PHOSPHIDO-BRIDGED COMPLEX (ETA(5)-C(5)ME(5))FE-2(CO)(4)(MU-CO)(MU-PPH(2))

Reactions of the unsymmetrical and homobimetallic phosphido-bridged complex (eta(5)-C(5)Me(5))Fe-2(CO)(4)(mu-CO)(mu-PPh(2)) (1) with various hydrosilanes gave rise to redistribution of the substituents on hydrosilanes. The reaction of 1 with 2 equiv. of secondary silane R(2)SiH(2) (R = Ph, p-Tol) caused effective aryl scrambling to afford a monoarylsilylene-bridged complex (eta(5)-C(5)Me(5))Fe-2(CO)(4)(mu-SiRH)(mu-PPh(2)) (2, R = Ph; 3, R = p-Tol) and a tertiary silane R(3)SiH (R = Ph, p-Tol). The signals of Si-29 and P-31{H-1} NMR spectra of these complexes appear at very low field (Si-29 NMR: 2, delta 209.1, (1)J(Si-H) = 185 Hz, (2)J(Si-P) = 26 Hz; 3, delta 209.1, (1)J(Si-H) = 185 Hz, (2)J(Si-P) = 27 Hz. P-31 NMR: 2, delta 224.5; 3, delta 225.0). Complex 2 and Ph(3)SiH were also formed by the reaction of 1 with 1 equiv. of dihydrodisilane HPh(2)SiSiPh(2)H. Similarly, the reaction of 1 with alkyldisilane HMe(2)SiSiMe(2)H proceeded smoothly to give the alkyl-scrambling product (eta(5)-C(5)Me(5))Fe-2(CO)(4)(mu-SiMeH)(mu-PPh(2)) (4) and Me(3)SiH. Some intermediates were observed in each reaction by NMR spectroscopy. A reaction mechanism containing silyl(silylene) intermediates is proposed.