Synthesis, properties and molecular structure of trans-hydroxobis(2, 2′-bipyridine)nitrosylruthenium(2+): influence of axial ligand on characteristics of nitrosyl moiety in trans-[Ru(NO)XL4]n+ (X=OH, Cl; L=py, 1/2(bpy)) type complexes

The macrocyclic effect and vasodilation response based on the photoinduced nitric oxide release from trans-[RuCl(tetraazamacrocycle)NO]2+

“…NO back-bonding as a consequence of the decrease of the electron density on ruthenium. The nitrosyl ammine ruthenium complexes are stable at pHs lower than 9 [6], which is contrary to the cis-[Ru(bpy) 2 L(NO)] n+ complexes, for which the nitrosyl species exist only at pHs lower than 6.1 [13,15], where the coordinated nitrosonium undergoes nucleophilic attack to form the nitro ligand. This effect was attributed to the high electron density under ruthenium(II) in the tetraamineruthenium(II) complexes providing strengthening of the Ru II -NO + back-bonding.…”

“…Considering those characteristics of a macrocyclic complex and the possibility to develop a variety of new NO donors that offer several advantages over conventional NO donors, that we believe in [RuCl(tetraazamacrocycle)NO] 2+ complexes as possible nitric oxide donor agents. In fact, the thermodynamic, kinetic and some pharmacological properties of [RuL(macrocycle)NO] n+ complexes where the macrocycle is cyclam (cyclam = 1,4,8,11-tetraazacyclotetradecane) [26][27][28], dioxocyclam [28] or [15]aneN 4 (1,4,8,12-tetraazacyclopentadecane) [16,29,30] have been described. Apparently all the studied complexes show great capability to function as NO delivery agents by having accessible reduction potentials that result in NO release [16,[25][26][27][28][29][30].…”

Synthesis and characterization of trans-[Ru(NO)Cl(L)4](PF6)2 (L = isonicotinamide; 4-acetylpyridine) and related species

“…It should be noted that tetrakispyridine and bisbipyridine nitrosyl complexes were isolated as hydroxo species even at H + concentrations as high as 6 mol L À1 [12,19]. With regard to the presence of the nitrosyl ligand in the metal coordination sphere, the trans ligand to NO is more acidic than in the complexes without the coordinated NO.…”

Chromatographic Investigation of Ruthenium Nitrosyl Complex: No Interconversion and Reactions With Biological Reductants

“…higher rate constant at high pH values. 27,52,53 The detection of the chemical specie formed in nitrite complex solution when it is submitted to different pH conditions was monitored by HPLC ( Figure 2). Figure 2a showed 3+ (compound 2, t R = 6.81 min) complexes ions, with their respective UV-Vis spectra.…”

“…[27][28][29][30][31][32][33][34] These species exhibit quite distinct overall charge, which can strongly alter interaction with reverse phase column.…”