TY - JOUR
T1 - Ligand substitution, pH dependent deoxygenation, and linkage isomerization reactions of the 2,2′-bipyridinetetranitroruthenate dianion
AU - Freedman, Daniel A.
AU - Janzen, Daron E.
AU - Vreeland, Jennifer L.
AU - Tully, Hannah M.
AU - Mann, Kent R.
PY - 2002/8/1
Y1 - 2002/8/1
N2 - The reaction of the [Ru(bpy)(NO2)4]2- (bpy = 2,2′-bipyridine) ion in aqueous solutions produces two different nitrosyl complexes, depending on the pH of the solution. At acidic pH, complex cis, cis-Ru(bpy)(NO2)2(ONO)(NO) was isolated. At neutral or basic pH, [Ru(bpy)(NO2)4]2- reacts to give cis, trans-Ru(bpy)(NO2)2(NO)(OH). Both new complexes were fully characterized by elemental analysis and UV-vis, IR, 1H NMR, and 15N NMR spectroscopy. A single-crystal x-ray structure of cis, trans-Ru(bpy)(NO2)2(NO)(OH) was also obtained. cis,cis-Ru(bpy)(NO2)2(ONO)-(NO) isomerizes in acetone or water solution to give a mixture of the trans, cis-Ru(bpy)(NO2)2(ONO)(NO) and cis,-cis-Ru(bpy)(ONO)2(NO2)(NO) linkage isomers as determined by 1H and 15N NMR spectroscopy. A single-crystal x-ray structure of a solid solution of cis,cis-Ru(bpy)(ONO)2(NO2)(NO)/trans, cis-Ru(bpy)(NO2)2(ONO)(NO) was also obtained. This pair of isomers is the first crystallographically characterized compound with nitro, nitrito, and nitrosyl ligands. The kinetic studies of the Ru-NO2→Ru-NO conversion reactions of [Ru(bpy)(NO2)4]2- in buffered solutions from pH 3 to pH 9 complement previous studies of the reverse reaction. The reactions are first order in [Ru(bpy)(NO2)4]2-. At high pH, the reaction is independent of the concentration of H+ while, at low pH, the reaction is first order in the concentration of H+. The rate determining step of the high pH reaction involves breakage of the Ru-NO2 bond while, at low pH, the mechanism involves a rapid reversible protonation of a NO2 ligand followed by the rate determining loss of hydroxide to produce a nitrosyl ligand.
AB - The reaction of the [Ru(bpy)(NO2)4]2- (bpy = 2,2′-bipyridine) ion in aqueous solutions produces two different nitrosyl complexes, depending on the pH of the solution. At acidic pH, complex cis, cis-Ru(bpy)(NO2)2(ONO)(NO) was isolated. At neutral or basic pH, [Ru(bpy)(NO2)4]2- reacts to give cis, trans-Ru(bpy)(NO2)2(NO)(OH). Both new complexes were fully characterized by elemental analysis and UV-vis, IR, 1H NMR, and 15N NMR spectroscopy. A single-crystal x-ray structure of cis, trans-Ru(bpy)(NO2)2(NO)(OH) was also obtained. cis,cis-Ru(bpy)(NO2)2(ONO)-(NO) isomerizes in acetone or water solution to give a mixture of the trans, cis-Ru(bpy)(NO2)2(ONO)(NO) and cis,-cis-Ru(bpy)(ONO)2(NO2)(NO) linkage isomers as determined by 1H and 15N NMR spectroscopy. A single-crystal x-ray structure of a solid solution of cis,cis-Ru(bpy)(ONO)2(NO2)(NO)/trans, cis-Ru(bpy)(NO2)2(ONO)(NO) was also obtained. This pair of isomers is the first crystallographically characterized compound with nitro, nitrito, and nitrosyl ligands. The kinetic studies of the Ru-NO2→Ru-NO conversion reactions of [Ru(bpy)(NO2)4]2- in buffered solutions from pH 3 to pH 9 complement previous studies of the reverse reaction. The reactions are first order in [Ru(bpy)(NO2)4]2-. At high pH, the reaction is independent of the concentration of H+ while, at low pH, the reaction is first order in the concentration of H+. The rate determining step of the high pH reaction involves breakage of the Ru-NO2 bond while, at low pH, the mechanism involves a rapid reversible protonation of a NO2 ligand followed by the rate determining loss of hydroxide to produce a nitrosyl ligand.
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U2 - 10.1021/ic0255205
DO - 10.1021/ic0255205
M3 - Article
C2 - 12132905
AN - SCOPUS:0036074491
SN - 0020-1669
VL - 41
SP - 3820
EP - 3829
JO - Inorganic chemistry
JF - Inorganic chemistry
IS - 15
ER -