Experimental SectionMaterials. [Ru(CO)3Cl2]2 was purchased from Johnson & Matthey, and 2,2′-bipyridine and 4,4′-dimethyl-2,2′-bipyridine from were purchased Aldrich Chemicals. 6,6′-Dimethyl-2,2′-bipyridine was obtained from the University of Oulu, where it was synthesized according to the literature method. 16 Ru(bpy)(CO)2Cl2 and its dimethyl-substituted analogues were synthesized from [Ru(CO) 3Cl2]2 and 2,2′-bipyridine reagents by refluxing in THF as described earlier. 17,18 HNO3 (65%, J. T. Baker) and HCl (37%, Merck) were of analytical grade and were used as received. Ligand substitution reactions were carried out in a Berghof 60 mL digestive pressure bomb with a PTFE liner. 19 All manipulations were performed in air.Characterization of the Products. Infrared spectra were measured with a Nicolet Magna FTIR spectrometer 750. X-ray diffraction data were collected with a Nicolet R3m or Syntex P21 diffractometer using graphite-monochromatized Mo KR radiation (λ ) 0.710 73 Å). Cell parameters were obtained from 25 automatically centered reflections. Intensities were corrected for background, polarization, and Lorentz effects. Data collection, data reduction, and cell refinement were carried out with the P3/P4-Diffractometer Program V 4.27. 20 The structures were solved by direct methods. The structure solution was carried out with the SHELXS 86 program and the structure refinement with the SHELXL 93 program. 21,22 All non-hydrogen atoms, except one of the NO 3 -oxygens in 3, were refined anisotropically. The NO3 -oxygen was disordered in two positions with an equal occupation factor (0.5) and refined isotropically. All hydrogens in 1, 2, and 4 were located from the difference Fourier map and refined isotropically with a fixed isotropic displacement parameter (U ) 0.08 Å 2 for uncoordinated H2O hydrogens in 2 and U ) 0.05 Å 2 for all other hydrogens). The hydrogens of the H 2O ligand in 3 and those of the H3O + ions in (H3O)2-[Ru(NO)Cl 5] could not be located from the difference Fourier map and were therefore omitted. Both oxygens of the H 3O + ions in (H3O)2-[Ru(NO)Cl 5] were surrounded by nine chlorines of the [RuCl5(NO)]2anions in the range 3.32-3.65 Å, allowing weak interactions and several orientations of the H 3O + ions. The crystallographic data are collected in Table 1.
Formation of Ru(dcbpy)Cl 3(NO) (1) (dcbpy ) 4,4′-Dicarboxy-2,2′-bipyridine).A 50 mg sample of Ru(4,4′-dmbpy)(CO) 2Cl2, 4 mL of hydrochloric acid (37%), and 50 µL of nitric acid (65%) were introduced into a 60 mL Berghof pressure vessel. The reaction mixture was heated to 240°C (temperature was maintained at 240°C for 2.5 h) and cooled slowly to room temperature (cooling rate about 16°C/ h). Dark red crystals (15.4 mg) formed during the cooling period were separated from the red solution by filtration and dried in air. The solid product was analyzed by X-ray diffraction and IR spectroscopic measurements as well as by elemental analysis. Anal. Calcd for 1: C, 29.95; N, 8.74; H, 1.68. Found: C, 30.05; N, 8.46; H, 1.59. IR (in KBr): ν(NO) 1912 ...