Properties of the oxo/aquo system (bpy)/sub 2/(py)RuO/sup 2 +//(bpy)/sub 2/(py)Ru(OH/sub 2/)/sup 2 +/

Journal Article · Sun Feb 01 04:00:00 EST 1981 · Inorg. Chem.; (United States)

DOI:https://doi.org/10.1021/ic50216a024· OSTI ID:6604984

Moyer, B A; Meyer, T J

The complex Ru(pby)/sub 2/(py)H/sub 2/O/sup 2 +/ (pby 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)/sub 2/(py)H/sub 2/O/sup 3 +/, has strongly enchanced properties as an acid, pK/sub a/ = 0.85 +- 0.03 at 25.0/sup 0/C, I = 1.0 M, compared to the Ru(II) complex, pK/sub a/ = 10.79 +- 0.01. The hydroxy complex, Ru(bpy)/sub 2/(py)OH/sup 2 +/, has also been isolated and characterized as its perchlorate salt. The two-electron product, Ru(bpy)/sub 2/(py)O/sup 2 +/, was shown to be a Ru(IV)-oxo complex by the results of a series of experiments including elemental analysis, solution conductivity, magnetism, and /sup 18/O 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)/sub 2/(py)RuO/sup 2 +/ /sup 0.53 V/ (bpy)/sub 2/(py)RuOH/sup 2 +/ /sup 0.42 V/ (bpy)/sub 2/(py)RuOH/sub 2//sup 2 +/. 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.

• Research Organization: Univ. of North Carolina, Chapel Hill
• OSTI ID: 6604984
• Journal Information: Inorg. Chem.; (United States), Journal Name: Inorg. Chem.; (United States) Vol. 20:2; ISSN INOCA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400201* -- Chemical & Physicochemical Properties
400400 -- Electrochemistry
AZINES
BIPYRIDINES
CHEMICAL PROPERTIES
CHEMICAL REACTIONS
CHEMISTRY
CHLORINE COMPOUNDS
COMPLEXES
ELECTROCHEMISTRY
HALOGEN COMPOUNDS
HETEROCYCLIC COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXIDATION
OXYGEN COMPOUNDS
PERCHLORATES
PH VALUE
PYRIDINES
REDOX POTENTIAL
RUTHENIUM COMPLEXES
SPECTROPHOTOMETRY
TITRATION
TRANSITION ELEMENT COMPLEXES