The synthesis, structure, and reactivity of the osmium(IV) trihydrido silyl complex, OsH3(SiMe3)(CO)(PPh3)2

Reaction between the five coordinate complex, Os(Ph)Cl(CO)(PPh3)(2), and HS iMe3 produces the osmium(IV) trihydrido silyl complex, OsH3(SiMe3)(CO)(PPh3 )(2) (1). The structure of 1 has been determined by single crystal X-ray cr ystallography and by multi-nuclear NMR spectroscopy. The structure has an a pproximately tetrahedral disposition of silyl, carbonyl and the two PPh3 li gands about osmium with the three classical hydride ligands located, one tr ans to CO, and the other two each approximately trails to a PPh3. Treatment of complex 1 with HSiR3 (R = Et, Ph), HSn(p-tolyl)(3), or HC2Ph gives OsH3 (SiR3)(CO)(PPh3)(2) (R = Et (2), Ph (3)), OsH2[Sn(p-tolyl)(3)](2)(CO)(PPh3) (2) (4) or OsH(C2Ph)(CO)(PPh3)(3) (5), respectively A likely intermediate i n these reactions is the coordinatively unsaturated complex, OsH2(CO)(PPh3) (2). (C) 2000 Elsevier science S.A. All rights reserved.