TY - JOUR
T1 - Properties of the Oxo/Aquo System (bpy)2(py)RuO2+/(bpy)2(py)Ru(OH2)2+
AU - Moyer, Bruce A.
AU - Meyer, Thomas J.
PY - 1981/2
Y1 - 1981/2
N2 - The complex Ru(bpy)2(py)H2O2+ (bpy is 2,2'-bipyridine; py is pyridine) has been prepared and found to undergo two reversible one-electron oxidations both by electrochemical means and by redox titrations using Ce(IV). The one-electron oxidation product, Ru(bpy)2(py)H2O3+, has strongly enchanced properties as an acid, pKa = 0.85 ± 0.03 at 25.0 °C, I = 1.0 M, compared to the Ru(II) complex, pKa = 10.79 ± 0.01. The hydroxy complex, Ru(bpy)2(py)OH2+, has also been isolated and characterized as its perchlorate salt. The two-electron product, Ru(bpy)2(py)O2+, was shown to be a Ru(IV)-oxo complex by the results of a series of experiments including elemental analysis, solution conductivity, magnetism, and 180 labeling. Given the acid-base properties of the complexes, redox potentials for the Ru(IV)/Ru(III) and Ru(III)/Ru(II) couples have the expected pH dependences, and at pH 7 the potentials are (vs. the SCE) (bpy)2(py)RuO2+ (bpy)2(py)RuOH2+ (bpy)2(py)RuOH22+. Our ability to isolate a stable Ru(IV)-oxo complex and the general redox characteristics of the system are discussed in the context of the oxidation of water, the reduction of oxygen, and the competitive formation of oxo-bridged dimers.
AB - The complex Ru(bpy)2(py)H2O2+ (bpy is 2,2'-bipyridine; py is pyridine) has been prepared and found to undergo two reversible one-electron oxidations both by electrochemical means and by redox titrations using Ce(IV). The one-electron oxidation product, Ru(bpy)2(py)H2O3+, has strongly enchanced properties as an acid, pKa = 0.85 ± 0.03 at 25.0 °C, I = 1.0 M, compared to the Ru(II) complex, pKa = 10.79 ± 0.01. The hydroxy complex, Ru(bpy)2(py)OH2+, has also been isolated and characterized as its perchlorate salt. The two-electron product, Ru(bpy)2(py)O2+, was shown to be a Ru(IV)-oxo complex by the results of a series of experiments including elemental analysis, solution conductivity, magnetism, and 180 labeling. Given the acid-base properties of the complexes, redox potentials for the Ru(IV)/Ru(III) and Ru(III)/Ru(II) couples have the expected pH dependences, and at pH 7 the potentials are (vs. the SCE) (bpy)2(py)RuO2+ (bpy)2(py)RuOH2+ (bpy)2(py)RuOH22+. Our ability to isolate a stable Ru(IV)-oxo complex and the general redox characteristics of the system are discussed in the context of the oxidation of water, the reduction of oxygen, and the competitive formation of oxo-bridged dimers.
UR - http://www.scopus.com/inward/record.url?scp=0001753253&partnerID=8YFLogxK
U2 - 10.1021/ic50216a024
DO - 10.1021/ic50216a024
M3 - Article
AN - SCOPUS:0001753253
SN - 0020-1669
VL - 20
SP - 436
EP - 444
JO - Inorganic Chemistry
JF - Inorganic Chemistry
IS - 2
ER -