Synthesis and structural characterization of the complexes [Os3(CO)10(CON3Ph)(NCMe)] and [Os3(CO)10(CON3Ph)(NC5H5)

Abstract

The clusters [Os3(CO)11(NCMe)] and [Os3(CO)11(NC5H5)] have been treated with phenyl azide to give [Os3(CO)10(CON3Ph)(L)][L = NCMe (1) or NC5H5(2)], the structures of which in the solid state were established by X-ray crystallography. Complex (1) crystallises in space group P with a= 9.029(3), b= 12.720(5), c= 13.433(5)A, α= 102.69(2), β= 102.52(2), γ= 104.75(2)°, and Z= 2. The structure was solved by a combination of direct methods and Fourier-difference techniques, and refined by blocked-cascade least squares to R= 0.057 for 3 739 unique diffractometer data. Complex (2) crystallises in the monoclinic space group P21/n with a= 9.311(4), b= 16.707(11), c= 20.241(15)A, β= 101.88(5)°, and Z= 4. The structure was solved using the same techniques as for (1), and refined by blocked-cascade least squares to R= 0.080 for 2 566 diffractometer data. In both complexes the Os atoms define a triangle with one edge extended to be non-bonding [3.612(2)A in (1) and 3.615(2)A in (2)]. This long edge is bridged by one of the terminal N atoms of the azide. The N atom at the other end of the azide, bound to the phenyl ring, is co-ordinated to the carbon atom of the adjacent equatorial carbonyl group. The other bridged Os atom has an NCMe group [in (1)] or a NC5H5 ligand [in (2)] co-ordinated in an axial site.