The structures of RuC3(NO)(P(C6H5)3)2 and RuCl3(p-NNC6H4CH3)(P(C6H5)3)2·CH2Cl2 have been determined crystallographically. Both complexes possess a similar pseudooctahedral geometry with trans phosphine ligands and meridional chloro ligands. The short Ru-N and N-X (X = O, N) distances suggest that both nitrosyl and aryldiazo ligands are good Π acceptors; however, subtle but distinct differences in the two ligands suggest that NO is the better Π acceptor. The much greater steric bulkiness of the aryldiazo ligand has a pronounced effect on the intramolecular interactions within the complex and on the three-dimensional packing of the complex in the solid state. Both Ru-N-X angles are essentially linear. The N(1)-N(2)-C(phenyl) angle at 137.1 (5)° in the diazo complex is unusually large. The Ru-Cl(trans to N) distances compared with the Ru-Cl(trans to Cl) distances are shortened by 0.041 (3) Å in the nitrosyl complex and by 0,008 (3) Å in the diazo complex. Both compounds are considered to be Ru(II) complexes of NO+ or NNAr+, with the respective ligands acting as three-electron donors. The nitrosyl complex crystallizes from dichloromethane-methanol as solvent-free crystals in space group C2h6-I2/a with a = 15.877 (3) Å, b = 9.540 (2) Å, c = 22.326 (4) Å, β = 102.79 (1)°, and Z = 4. Each molecule has imposed C2 symmetry. On the basis of 2671 unique reflections with Fo2>3ct(Fo2), the structure was refined by full-matrix, least-squares methods to R = 0.058 and Fw = 0.068. Some important molecular parameters are Ru-N = 1.737 (7) Á, N-O = 1.142 (8) Á, and Ru-N-0 = 180.0°. The tolyldiazo complex crystallizes from dichloromethane as solvated crystals in space group C2hs-P21/c with a = 12.406 (8) Á, b = 18.421 (13) Á, c = 18.565 (13) Á, ß = 93.05 (1)°, and Z = 4. The molecule has no imposed symmetry, but approximates G symmetry. On the basis of 5100 unique reflections with Fo2> 3σ(Fo2), the structure was refined by full-matrix, least-squares methods to R = 0.058 and Rw= 0.067. Some important molecular parameters in the diazo complex are Ru-N(1) = 1.784 (5) Å, N(l)-N(2) = 1.158 (6) Å, N(2)-C(phenyl) = 1.376 (6) A, and Ru-N(l)-N(2) = 171.9 (5) °. Both structures consist of discrete monomeric molecules of the respective complex. The values of v(NO) and v(NN) for these and other nitrosyl and aryldiazo complexes are discussed, and some empirical rules are suggested for distinguishing between bent and linear nitrosyl ligands and between doubly bent and singly bent aryldiazo ligands on the basis of the N-O and N-N stretching frequencies. The syntheses of [M(NO) (diphos)2] [PF6] 2(M = Rh, Ir) are reported.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Inorganic Chemistry