Nitrosyl complexes of rhenium. Part 2. Crystal and molecular structure of dihydridonitrosyltris(triphenylphosphine)rhenium(I)?benzene(2/1)

The crystal and molecular structure of the title compound has been determined by Patterson and Fourier methods from three-dimensional X-ray data collected by diffractometer. Crystals are orthorhombic, space group Pca21, with cell constants a = 25.069(6), b = 18.737(4), and c = 20.644(5) Å. The structure has been refined by least-squares methods to R 0.048 for 2 938 independent reflections. The two crystallographically independent molecules in the asymmetric unit are very similar and exhibit markedly distorted octahedral geometry, with one phosphine ligand, the NO group, and the two hydrido-ligands (mutually cis) in equatorial positions, with the other two phosphine ligands axial, largely bent toward the hydrido H atoms. The three Re-P distances are 2.370(7), 2.439(7), and 2.403(8) Å in the first molecule and 2.401(6), 2.498(8), and 2.386(8) Å; in the second. The nitrosyil groups are linked linearly to the metal atoms, as NO+ ligands, with Re-N 1.77(2) and 1.73(2) and N-O 1.25(3) and 1.24(3) Å; in the two molecules. The largest deviation from ideal geometry is shown by the axial P-Re-P angles [143.4(3) and 143.0(3)°].