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The ruthenium(II) compounds cis -[Ru(bpy) 2 (4-bzpy)(CO)](PF 6 ) 2 ( I ) and cis -[Ru(bpy) 2 (4-bzpy)(Cl)](PF 6 ) ( II ) (4-bzpy = 4-benzoylpyridine, bpy = 2,2′-bipyridine) were synthesized and characterized by spectroscopic and electrochemical techniques. The crystal structure of II was determined by X-ray diffraction. The photochemical behavior of I in aqueous solution shows that irradiation with ultraviolet light (365 nm) releases both CO and 4-bzpy leading to the formation of the cis -[Ru(bpy) 2 (H 2 O) 2 ] 2 + ion as identified by NMR and electronic spectroscopy. Carbon monoxide release was confirmed with the myoglobin method and by gas chromatographic analysis of the headspace. CO release was not observed when aqueous I was irradiated with blue light (453 nm). Changes in the electronic and 1 H NMR spectra indicate that I undergoes photoaquation of 4-bzpy to form cis -[Ru(bpy) 2 (CO)(H 2 O)] 2 + . Blue light irradiation of aqueous II released the coordinated 4-bzpy to give the cis -[Ru(bpy) 2 (H 2 O)(Cl)] 2 + ion. When the latter reaction was carried out in the presence of the nucleobase guanine, Ru-guanine adducts were formed, indicating that the metal containing photoproduct may also participate in biologically relevant reactions. The photochemical behavior of I indicates that it can release either CO or 4-bzpy depending on the wavelength chosen, a feature that may have therapeutic application. [ABSTRACT FROM AUTHOR]

Abstract: Ruthenium(II) carbonyl complexes containing triarylphosphines and hybrid ligands PPh2-X (X= o-dimethylaniline – P–N, o-pyridine – P-Py, or o-anisole – P–O) were synthesized and characterized. Six new complexes with the formula cis,trans-[RuCl2(CO)(PPh2-X)(PR3)] (X= o-dimethylaniline, R=Ph 1a; X= o-pyridine, R=Ph 2a; X= o-anisole, R=Ph 3a; X= o-dimethylaniline, R= p-tol 1b; X= o-pyridine, R= p-tol 2b; and X= o-anisole, R= p-tol 3b) were obtained by starting from the appropriate precursors, [RuCl2(CO)(DMF)(PPh3)2] or [RuCl2(CO)(DMF)(P{p-tol}3)2]. The two chlorine atoms are in cis position to each other, and the monophosphine (PPh3 or P{p-tol}3) is in trans position to the nitrogen or oxygen of the PPh2-X ligand. The synthesized complexes were characterized by 1D–1H, 31P{1H} and 2D-correlations HMBC 31P–1H NMR, vibrational spectroscopy, elemental analysis, and X-ray diffraction structural determination (for complexes 1a, 2a·CH2Cl2 , 3a, and 3b·CH2Cl2 ). Only the complexes containing the P–O ligand (3a and 3b) reacted with carbon monoxide (at 1atm and room temperature). The NMR (31P{1H}, 1H) data was compatible with carbon monoxide coordination at the OCH3 position, which led to the formation of dicarbonyl complexes [RuCl2(CO)2(P–O)(PR3)] (R=Ph 4a or p-tol 4b), and proved the hemilabile behavior of the P–O ligand. In addition, the complexes underwent isomerization in solution when exposed to ambient light, and the products were analyzed by 31P{1H} NMR. The X-ray structures and the chemical shift in the 31P NMR spectra were correlated and discussed. [Copyright &y& Elsevier]

Abstract: The “Ru(P–P)” unit (P–P=diphosphine) is recognized to be an important core in catalytic species for hydrogenation of unsaturated organic substrates. Thus, in this study we synthesized six new complexes containing this core, including the binuclear complex [(dppb)(CO)Cl2Ru-pz-RuCl2(CO)(dppb)] (pz=pyrazine) which can be used as a precursor for the synthesis of cationic carbonyl species of general formula [RuCl(CO)(dppb)(N–N)]PF6 (N–N=diimine). Complexes with the formula [RuCl(py)(dppb)(N–N)]PF6 were synthesized by exhaustive electrolysis of these carbonyl compounds or from the precursors [RuCl2(dppb)(N–N)]. The new complexes were characterized by microanalysis, conductivity measurements, IR and 31P{1H} NMR spectroscopy, cyclic voltammetry and X-ray crystallography. [Copyright &y& Elsevier]