The unusually fast reactions between ruthenium(iii)-ammine complexes and NO revisitedElectronic supplementary information (ESI) available: UV-Vis spectrum of [Ru(NH3)5NO]3+ and titration curve for the acid dissociation of [Ru(NH3)5(H2O)]3+. See http://www.rsc.org/suppdata/dt/b2/b210256k/

Reactivity of Inorganic Radicals in Aqueous Solution

“…One fascinating reaction is that of NO with [Ru(NH 3 ) 6 ] 3 þ to produce [Ru(NH 3 ) 5 NO] 3 þ ; in acidic media, the reaction is pH independent and first order in both reactants. [168][169][170] An associative displacement of coordinated NH 3 by NO is consistent with these observations, and it is in agreement with more general reports of associative substitution at Ru(III). 171 A similar description applies to the reactions of NO with [Ru(NH 3 ) 5 Cl] 2 þ and [Ru(NH 3 ) 5 (H 2 O)] 3 þ .…”

“…171 A similar description applies to the reactions of NO with [Ru(NH 3 ) 5 Cl] 2 þ and [Ru(NH 3 ) 5 (H 2 O)] 3 þ . 169 The reactions of NO with cis-and trans-[Ru III (terpy)(NH 3 ) 2 Cl] 2 þ are multistep processes, and the first step is the reversible displacement of Cl À by NO; surprisingly, it is argued that the second step is the conversion of Ru III --NO to Ru II --NO þ . 172 In further steps, the Ru(terpy) complexes release nitrite and ammonia.…”

Synthesis, characterization and cytotoxic activities of the [RuCl2(NO)(dppp)(L)]PF6 complexes

“…The labilization of the coordinated NO generating a new and unknown complex could be responsible for the electrochemical process at about 300 mV in all four complexes; and the presence of free NO in the solution could be responsible for the fourth anodic process at approximately 800 mV. Similar behavior was observed for the compounds of type trans-[Ru(NH 3 ) 4 P(OEt) 3 NO] 3+ [51,52] with varied substitutes in the phosphate ligand, in which the redox process involving coordinated NO + is not very defined and two additional processes were observed. This is the redox pair associated to the species without NO generated in the solution and, around 800 mV, an irreversible process attributed to the oxidation of the free NO.…”

“…Until now, most progress in this area has been achieved from studies using transition metal complexes. Ruthenium complexes are by far the most studied and their relation with nitric oxide acting as scavengers [2][3][4][5][6][7] or as NO releasers has been well explored in the literatures [8][9][10][11][12]. It is worth to point out that ruthenium compounds normally exhibit fewer general toxicity problems than other metal-based drugs [13], as documented by clinical experiences with a sort of ruthenium complexes [14][15][16][17][18] including some containing coordinated nitric oxide [10].…”

Mechanisms of Nitric Oxide Reactions Mediated by Biologically Relevant Metal Centers

“…This mechanism gains further support from subsequent studies of the temperature [70] and hydrostatic pressure effects [71] on the kinetics that determined the activation enthalpy ΔH { to be small (36 kJ mol À1 ), the activation entropy ΔS { to be large and negative (-138 J K À1 mol À1 ), and the activation volume ΔV { also to be large and negative (À13.6 cm À3 mol À1 ).…”