Synthesis, Characterization, and NO Release Study of the <i>cis</i>‐ and <i>trans</i>‐[Ru(Bpy)₂(SO₃)(NO)]⁺ Complexes

Abstract

Abstract Aiming at the development of novel NO donors, the synthesis and reactivity of the trans ‐[Ru(bpy) 2 (SO 3 )(NO)](PF 6 ) and cis ‐[Ru(bpy) 2 (L)(NO)](PF 6 ) n complexes (L = imidazole, isonicotinamide, or sulfite ions) were investigated. The complexes were characterized and the NO release capabilities were evaluated. The rate constant for NO dissociation for the cis ‐[Ru(bpy) 2 (SO 3 )(NO)] + complex is k = 2.0 · 10 –3 s –1 . The cis and trans ‐ [Ru(bpy) 2 (SO 3 )(NO)] + complexes showed promising physical‐chemical properties towards nitric oxide generation, and great stability towards hydroxide attack in the 2.0–9.0 pH range. The reduction potential of the {RuNO} 6/7 process of the cis and trans ‐[Ru(bpy) 2 (SO 3 )NO] + complexes ( E 1/2 =–0.14 and –0.34 V vs. Ag/AgCl) is appropriated for reduction in vivo by biological reducing agents, with consequent NO release. (© Wiley‐VCH Verlag GmbH &amp; Co. KGaA, 69451 Weinheim, Germany, 2006)