The structure of RHCl((C6H5)CONCS)2(P(C6H5)3)2.(C2H5)2O has been determined crystallographicallv. The rhodium atom in the complex possesses pseudooctahedral geometry with trans phosphine ligands in the axial positions and the four equatorial positions being occupied by a chloro and a tridentate ligand, ((C6H5)CONCS)2. This novel ligand is formed by the condensation of two benzoyl isothiocyanate molecules joined together at the sulfur atom of one ligand and the isothiocyanate carbon atom of the second. The resulting ligand is bonded to the rhodium atom via a sulfur atom, a carbon atom, and an oxygen atom forming two fused five-membered metallocycles sharing the rhodium atom and the carbene carbon atom along a common edge. Bond lengths within the resulting chelate rings are intermediate between single- and double-bonded values and therefore suggest delocalization over the ligand framework. In addition the entire ligand is essentially planar thus facilitating any delocalized bonding. The Rh-C(carbene) bond (1.930 (6) Å) is the shortest rhodium-carbene distance yet observed and this carbene shows a strong trans influence resulting in a long Rh-Cl bond length of 2.455 (2) Å. The diethyl ether molecules, which are located in the cavities between the triphenylphosphine and ((C6H5)CONCS)2 ligands, are severely disordered and thus no satisfactory description of these molecules is possible. The complex crystallizes from methylene chloride-diethyl ether as bright orange prisms containing solvated diethyl ether. The space group is C2h5-P21/n with a = 21.184 (3) Å, b = 19.963 (2) Å, c = 12.226 (2) Å, β = 100.03 (1) °, V = 5092 Å3, and Z = 4. Based on 6266 unique reflections with Fo2 ≥ 3σ(Fo2) the structure was refined by full-matrix, least-squares techniques to give R = 0.061 and Rw = 0.079. The Rh-S and Rh-O distances are 2.287 (2) and 2.098 (4) Å, respectively.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Inorganic Chemistry