STEREOCHEMICALLY NONRIGID ORGANOMETALLIC MOLECULES .15. STRUCTURE OF ONE OF ISOMERIC C8H8RU2(CO)6 MOLECULES IN CRYSTALLINE COMPOUND

The crystal and molecular structures of one of the isomeric (cyclooctatetraene)diruthenium hexacarbonyls have been determined by means of a three-dimensional, X-ray crystal-structure analysis. The intensities of 3141 independent reflections were measured with a counter diffractometer. The structure was solved by Patterson and Fourier methods and refined using anisotropic thermal parameters by full-matrix least squares to a final unweighted discrepancy index of 0.05. Crystallographic data are : space group, P21/n; unit cell dimensions, a = 8.906 Å, b = 17.96 Å,c = 9.245 Å, β = 90.27° Z = 4; ρcalcd = 2.095 g/cm3, ρobsd = 2.091 g/cml The molecule possesses no symmetry in the crystal. It consists of an (OC)3Ru-Ru(CO)3 portion which is bonded to the ring by means of a π-allyl-metal bond to one Ru, an olefin-metal bond, and a carbon-metal σ bond to the other Ru (these descriptions are but rough approximations), and there is an uncoordinated C=C bond in the ring. The Ru–Ru line is nearly perpendicular to the unused C=C bond. The implications of this result with respect to the (different) structures previously postulated for the C3H8Fe2(CO)6 having a very similar nmr spectrum and some other molecules are discussed. © 1968, American Chemical Society. All rights reserved.