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Studies in nickel(IV) chemistry. Electron transfer kinetics of the reaction between tris(dimethylglyoximato)nickelate(IV) and hexacyanoferrate(II) in aqueous medium
Author(s) -
Sahu R.,
Neogi G.,
Acharya S.,
Panda R. K.
Publication year - 1983
Publication title -
international journal of chemical kinetics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.341
H-Index - 68
eISSN - 1097-4601
pISSN - 0538-8066
DOI - 10.1002/kin.550150811
Subject(s) - chemistry , protonation , aqueous solution , nickel , reaction rate constant , electron transfer , kinetics , electrophile , inorganic chemistry , dimethylglyoxime , tris , medicinal chemistry , ion , catalysis , organic chemistry , biochemistry , physics , quantum mechanics
The kinetics of electron transfer from hexacyanoferrate(II) to tris(dimethylglyoximato)‐nickelate(IV), Ni(dmg) 3 2− , to produce Fe(CN) 6 3− and Ni(dmgH) 2 , follows a pseudo‐first‐order disappearance in the Ni(IV). The pseudo‐first‐order rate constants k obs are linearly dependent on [Fe(CN) 6 4− ] 0 in a fiftyfold range of 2 × 10 −4 −1 × 10 −2 M , and the average values of k obs /[Fe(CN) 6 4− ] 0 range from 194 M −1 ·s −1 at pH = 5.20 to 0.2 M −1 ·s −1 at pH = 9.07 in aqueous medium at 35°C and μ = 0.57 M . Results are interpreted in terms of a probable mechanism involving rate‐determining outer sphere one‐electron transfer steps from the reductant and one‐protonated reductant species to the unprotonated and one‐protonated Ni(IV) species present in solution. The more electrophilic one‐protonated reductant species apparently reacts several orders of magnitude faster than the unprotonated one.