Premium
Kinetics and equilibrium constants of some pentacyanoferrate(II) complexes of nitrogen and sulfur containing heterocycles
Author(s) -
Baran Yakup,
Ülgen Ahmet
Publication year - 1998
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(1998)30:6<415::aid-kin3>3.0.co;2-v
Subject(s) - chemistry , kinetics , reaction rate constant , dissociation (chemistry) , rate determining step , nitrogen , sulfur , limiting , equilibrium constant , organic chemistry , catalysis , physics , quantum mechanics , mechanical engineering , engineering
The kinetics of the substitution reactions of Fe(CN) 5 H 2 O 3− ion with a series of nitrogen and sulfur containing heterocycles were studied in aqueous media. In the presence of excess ligand, varied over a large range of concentrations, second‐order rate constants were calculated at μ = 0.100 M NaClO 4 . Activation parameters for the formation reactions were found, Δ H *ast; and Δ S *, 28 ± 6 kJ/mol and 135±20 J/mol, respectively. The results are interpreted as being consistent with dissociative, SN 1 mechanism. The kinetics of formation and dissociation were studied by stopped‐flow technique at several temperatures. An investigation of the kinetics of exchange of coordinated heterocycles for 1,3,5‐triazine, yielded rate saturation that is typical of a limiting SN 1 mechanism. Activation parameters of the limiting first‐order specific rate of dissociations were found with Δ H * and Δ S * 53±2 kJ/mol and 105±5 J/mol, respectively. From the specific rates of formation and dissociation reactions the equilibrium constants were calculated. © 1998 John Wiley & Sons, Inc. Int J Chem Kinet: 30: 415–418, 1998