Abstract: | Synthesis and Characterization of a New Metallacyclic Compound of Osmium The bissilylated phosphorane, Me3SiNP(Ph2)CH2(Ph2)PNSiMe3 1 reacts with OsO4 via the migration of SiMe3 groups to give a new metallacycle 2 containing OsVIII. 1H, 31P, and 29Si n.m.r. spectroscopic investigations confirm the cyclic structure of 2 . |