Electron transfer. 75. Reduction of carboxylato-bound chromium(V) with vanadium(IV). Intervention of chromium(IV)

Journal Article · Wed Dec 18 04:00:00 EST 1985 · Inorg. Chem.; (United States)

DOI:https://doi.org/10.1021/ic00220a050· OSTI ID:5953466

Fanchiang, Y T; Bose, R N; Gelerinter, E; Gould, E S

The chelated (carboxylato)chromium(V) anion bis(2-hydroxy-2-ethylbutyrato)oxochromate(V) (I), ((Lig)/sub 2/Cr(O))/sup -/, reacts with oxovanadium(IV) to form a strongly absorbing species (lambda/sub max/ = 515 nm; epsilon = 1.7 x 10/sup 3/ M/sup -1/) in the presence of 2-hydroxy-2-ethylbutyric acid buffers (pH 2-4). EPR data support 1:1 stoichiometry with VO/sup 2 +/ in deficiency, indicating the formation of a chromium(IV) species by reduction. With excess VO/sup 2 +/ a chromium(III) product was obtained. Spectral and ion-exchange properties of this product correspond to those observed for the titanium(III) and iron(II) reductions of chromium(V) and are consistent with the formulation of the product as a bis(hydroxycarboxylate) chelate of (H/sub 2/O)/sub 2/Cr/sup III/. With excess vanadium(IV), the reaction exhibits triphasic kinetics. The remaining step of the reaction is the reduction of the chromium(IV) intermediate with VO/sup 2 +/. Rates for all steps increase with decreasing (H/sup +/) and level off at low (H/sup +/). The limiting rate constants for the formation of the chromium(IV) intermediate by the (Lig)/sub 3/Cr(O)/sup 2 -/ and (Lig)/sub 2/Cr(O)/sup -/ pathways are 2.8 x 10/sup 3/ and 2.2 x 10/sup 2/ M/sup -1/s/sup -1/. The bimolecular limiting rate constant for the reduction of chromium(IV) is computed to be 7.7 x 10/sup 2/ M/sup -1/ s/sup -1/. 33 references, 7 tables.

• Research Organization: Kent State Univ., OH
• OSTI ID: 5953466
• Journal Information: Inorg. Chem.; (United States), Journal Name: Inorg. Chem.; (United States) Vol. 24:26; ISSN INOCA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400301* -- Organic Chemistry-- Chemical & Physicochemical Properties-- (-1987)
CATIONS
CHALCOGENIDES
CHARGED PARTICLES
CHELATES
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CHROMIUM COMPLEXES
COMPLEXES
DATA
ELECTRON SPIN RESONANCE
ELECTRON TRANSFER
ELEMENTS
EXPERIMENTAL DATA
INFORMATION
IONS
KINETICS
MAGNETIC RESONANCE
METALS
NUMERICAL DATA
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
PH VALUE
REACTION KINETICS
REDUCTION
RESONANCE
TRANSITION ELEMENT COMPLEXES
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
VANADIUM
VANADIUM COMPOUNDS
VANADIUM OXIDES