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Kinetics and mechanism of the oxidation of some carboxylates by a nickel (III) oxime‐imine complex
Author(s) -
Saha Basudeb,
Dutta Amitava,
Gangopadhyay Sumana,
Banerjee Pradyot
Publication year - 1997
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/(sici)1097-4601(1997)29:3<225::aid-kin10>3.0.co;2-9
Subject(s) - chemistry , imine , oxime , nickel , kinetics , mechanism (biology) , photochemistry , organic chemistry , catalysis , physics , quantum mechanics , philosophy , epistemology
The kinetics of the oxidation of formate, oxalate, and malonate by |Ni III (L 1 )| 2+ (where HL 1 = 15‐amino‐3‐methyl‐4,7,10,13‐tetraazapentadec‐3‐en‐2‐one oxime) were carried out over the regions pH 3.0–5.75, 2.80–5.50, and 2.50–7.58, respectively, at constant ionic strength and temperature 40°C. All the reactions are overall second‐order with first‐order on both the oxidant and reductant. A general rate law is given as ‐ d/dt |Ni III (L 1 ) 2+ | = k obs |Ni III (L 1 ) 2+ | = ( k d + nk s |R|)|Ni III (L 1 ) 2+ |, where k d is the auto‐decomposition rate constant of the complex, k s is the electron transfer rate constant, n is the stoichiometric factor, and R is either formate, oxalate, or malonate. The reactivity of all the reacting species of the reductants in solution were evaluated choosing suitable pH regions. The reactivity orders are: k HCOOH > k HCOO −; k H 2 ox> k Hox −> k ox 2−, and k H 2 mal> k Hmal −< k mal 2−for the oxidation of formate, oxalate, and malonate, respectively, and these trends were explained considering the effect of hydrogen bonded adduct formation and thermodynamic potential. © 1997 John Wiley & Sons, Inc. Int J Chem Kinet 29: 225–230, 1997.