The crystal and molecular structure of PPN[Os3(CO)10(NO)] (PPN = [P(C6H5)3]2N+) has been determined by a single-crystal X-ray analysis. The compound crystallizes in the monoclinic crystal system in space group P21/c with a = 16.848 (2) Å, b = 17.015 (2) Å, c = 17.740 (2) Å, β = 107.25 (1)°, and ρ(calcd) = 1.94 g cm-3 for Z = 4 with molecular weight 1419.26. Diffraction data were recorded on a Stoe-Siemens diffractometer, and the structure was refined to R = 0.045 for 6261 observed diffractometer data. The three osmium atoms lie at the vertices of an isoceles triangle with the nitrosyl ligand bridging the shorter Os-Os edge. The arrangement of the three terminal carbonyl groups bound to each of the metal atoms bridged by the nitrosyl ligand is different from that in the saturated HOs3(CO)10(X) clusters, and the bridged Os-Os bond length of 2.751 (1) Å is shorter than that found in any of these related neutral species. This difference between the two types of systems may be attributed to the absence of a bridging hydride in the anion. The lack of this hydride is also proposed to be responsible for the lower activation barrier for CO scrambling observed in [Os3(CO)10(NO)]-.
|Original language||English (US)|
|Number of pages||4|
|State||Published - Mar 1984|