c43 Journal of Organometallic Chew&by, 396 (1990) C43-C46 Elsevier Sequoia S-A., Lausanne zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA JOM 21286PC Preliminary communication Synthesis and X-ray structural characterisation of the phosphido-bridged triosmium carbonyl cluster (OS&p-H) (CO) 10( p-P( C6 F,)H)]: cleavage zyxwvutsrqponmlkjihgfedcbaZYXWVU of a P-C bond of a secondary phosphine H.G. Ang, W.L. Kwik, W.K. Leong Department of Chemistry, National University of Singapore, Lower Kent Ridge Rod Singapore 051 I (Republic of Singapore} Brian F.G. Johnson, Jack Lewis and Paul R. Raithby University Chemical Laboratory, Lensfield R& Cambridge CB2 1 E W (U.K.) (Received June 29th, 1990) Abstract zyxwvutsrqponmlkjihgfedcbaZYXWVUTSRQPONMLKJIHGFEDCBA The reaction of the anion [Os,H(CO),,]- with bis(pentafluorophenyl)phosphine, (C,F,),PH, results in the cleavage of a P-C bond and the formation of the bridged phosphido cluster [Os,(p-H)(CO),,&P(CgF6)H)]. The structure of this product has been confirmed by a single-crystal X-ray diffraction study which shows that the P(C,F,)H ligand and the hydrido bridge the long edge (2.916(l) A) of the isosceles osmium triangle. The importance of reactions involving P-C bond cleavage of coordinated phos- phines in catalytic systems has long been recognised, and there have been many studies on model bi- and polynuclear organometalhc complexes containing alkyl- and aryl-phosphines [l]. However, there have been relatively few studies of P-C bond cleavage reactions for phosphines which contain fluorophenyl substituents, although the electron-withdrawing nature of this substituent might be expected to modify the reactivity of the ligand. We now report the synthesis and characterisa- tion of [Os,(,+H)(CO)&-P(c,F,)H] (1) prepared by the reaction of the [Os,H(CO),,I- anion with the tertiary phosphine (C,F,),PH. The cluster [OS,@-H)(CO),,(p-P(C,F5)H)] (1) was obtained as a yellow solid from the reaction of [(Ph,P),N][Os,H(CO),,] with bis(pentafluorophenyl)phos- phine, in CH,OH, at room temperature. The yellow crystalline product was ob- 0022-328X/90/$03.50 Q 1990 - Elsevier Sequoia S.A.