X-Ray and neutron diffraction study of 1,1,1,2,2,2,3,3,3-nonacarbonyl-1,2;1,3-di-µ-hydrido-µ3-sulphido-triangulo-triosmium

Abstract

The title complex [Os₃(CO)₉H₂(S)] crystallises in the monoclinic space group C2/c with a= 20.476(10), b= 13.952(7), c= 12.939(6)Å, β= 123.84(3)°, and Z= 8. Simultaneous refinement of a single parameter set to 2 436 X-ray [(sinθ)/λ > 0.45] and 1 292 neutron data has led to R 0.038 (X-ray) and 0.037 (neutron). The two longer edges of the Os₃ isosceles triangle are bridged by hydrides, which lie on the opposite side of the Os₃ plane to the triply bridging sulphur atom. Each osmium is also bonded to three terminal carbonyls. The Os–H–Os linkages can be described as ‘open’ three-centre two-electron bent bonds, with little direct Os–Os interaction. Both hydride bridges are significantly asymmetric, the hydrogen atoms being ca. 0.025 Å closer to the unique osmium. The mean Os–H distance is 1.819 Å, and both Os–H–Os angles are 106.5(2)°.