Crystal and molecular structure of octacarbonyl-µ-(1,2,3,4-tetraphenyl-but-2-ene-1,1,4,4-tetrayl)-triangulo-triosmium (Ph4C4)Os3(CO)8

Abstract

The title compound crystallizes in the monoclinic system, space-group P2₁/n, Z = 4, a₀= 9·36(2), b₀= 33·77(6), c₀= 10·76(2)Å, β= 98° 47′(5′). An X-ray crystal-structure analysis has been made by use of 2178 non-zero reflexions collected with an automatic diffractometer; the structure was solved by Patterson and Fourier methods and refined by least-squares techniques to R 0·12. The molecule is built up by a cluster of three osmium atoms, at the corners of an almost equilateral triangle, and by the organic ligand; the osmium atoms are linked with two [Os(1)] or three [Os(2) and Os(3)] carbonyl groups. The chelation between the two parts of the molecule is partially attained through µ-bonds; the possible existence of a three-centre C⋯H⋯Os bond or of an Os–H hydride bond is discussed.