Premium
Kinetics and Mechanism of Reduction of Tris(acetylacetonato)cobalt(III) by Hydrazine in Acid Media
Author(s) -
Basak A. K.,
Banerjea D.
Publication year - 1976
Publication title -
zeitschrift für anorganische und allgemeine chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.354
H-Index - 66
eISSN - 1521-3749
pISSN - 0044-2313
DOI - 10.1002/zaac.19764250312
Subject(s) - chemistry , cobalt , perchloric acid , reaction rate constant , protonation , ionic strength , hydrazine (antidepressant) , kinetics , medicinal chemistry , ligand (biochemistry) , electron transfer , tris , aqueous solution , inorganic chemistry , photochemistry , organic chemistry , ion , biochemistry , physics , receptor , chromatography , quantum mechanics
The kinetics of reduction of tris(acetylacetonato)cobalt(III) by hydrazine in aqueous perchloric acid medium have been studied under different conditions. The complex Co(acac) 3 and its protonated form Co(acac) 2 (acacH + ) are both reduced by N 2 H 4 with specific rate constants k R and k H,R respectively. These reactions occur concurrently with the self reduction of the complex in acid media having a specific rate constant k H . From detailed analysis of the effects of acid and hydrazine concentration on the rate, values of k H , k R and k H,R have been determined at 30°, 40° and 50°C at an ionic strength of 2 and from these the corresponding activation parameters ΔH ≠ and ΔS ≠ have been evaluated. The mechanism appears to involve the formation of intermediates in which N 2 H 6 2+ is hydrogen bonded to Co(acac) 3 and Co(acac) 2 (acacH + ) respectively each of which possibly decomposes (rate determining) by H atom transfer from N 2 H 6 2+ to the bound acetylacetonate ligand, leading to an electron transfer to cobalt(III) forming cobalt(II).