From the observed conditions hkl, h + k = 2n, and hOl, I = 2n, the two possible space groups are Cc (No. 9) and C2/c (No. 15). Solution of the structure was accomplished by Patterson methods. Both the anion and the cation can be located on crystallographic 2-fold axes. Thus C2/c is the space group of choice.An absorption correction was applied.30 Four low-angle reflections appeared to be affected by extinction and were removed from the set of reflections used in refinement. The lattice molecule of chloroform was disordered and was given an occupancy of 0.5 on the basis of Fourier peak heights. It was refined with inter-chlorine and chlorine-carbon distance constraints by the method of additional observational eq~ations.~ Another site in the lattice is occupied by two partial molecules of dichloromethane that are rotated approximately 90' with respect to their chlorine-chlorine vectors. They were refined with fixed Us of 0.08 .AZ and variable occupancies that converged at 0.309 (9) and 0.195 (9), respectively. Hydrogen atoms were included in the structure factor calcualtion at idealized positions by using a model in which the hydrogen atoms ride on the bonded carbon and C-H is 0.96 A. In the final cycles (30) XAW produces an absorption tensor from an expression relating F, and F,: Moezzi, B. Ph.D. Thesis, University of California, Davis, CA, 1988.of refinement all non-hydrogen atoms were assigned anisotropic thermal parameters except the carbon of chloroform and the chlorines of dichloromethane (the latter carbon atom was not located). In the final difference map the largest feature was 2.1 e A-' in height, in the vicinity of one of the chloroform molecules. X-ray Structure Determination and Refmemeat for 3. Orange blocks of Ru(dpma),Cl, were obtained by diffusion of methanol into a dichloromethane solution of the complex. Data collection, treatment, and refinement followed by the procedures outlined for 2. A value of 0.81 e A" was found for the largest feature in the final difference map. This was 0.69 A away from C(19). Acknowledgment. We thank the National Science Foundation (Grant CHE 8519557) for financial support and Dr. J. de Ropp of the UCD NMR facility for assistance with the NMR experiments.
Supplementary Material Available:Listings of all bond lengths, bond angles, hydrogen atom positions, anisotropic thermal parameters, and data collection parameters (10 pages); listings of observed and calculated structure factors (58 pages). Ordering information is given on any current masthead page.Contribution from the A series of ruthenium(I1) complexes of the type R u C I~( C O )~P~ (P = BzljP, PhjP, PhzMeP, PhMezP, Me3P) have been prepared and characterized by elemental analyses, physical properties, infrared spectroscopy, UV-visible spectroscopy, and IH, 13C(1H) and ,IP( IHJ NMR spectroscopy. The first-formed complex, with all ligand pairs trans (ttt), thermally isomerizes in solution to produce the isomer with all ligand pairs cis (ccc). This ccc isomer further isomerizes in solution to produce the thermodynam...
