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Kinetics of the mercury(II)‐catalyzed substitution of coordinated cyanide ion in hexacyanoruthenate(II) by nitroso‐R‐salt
Author(s) -
Naik Radhey M.,
Agarwal Abhinav,
Verma Amit K.,
Yadav Shiv Bali S.,
Kumar Basant
Publication year - 2009
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.20391
Subject(s) - chemistry , ionic strength , catalysis , salt (chemistry) , cyanide , nitroso , inorganic chemistry , kinetics , absorbance , solvent , ionic bonding , reaction rate constant , reaction rate , ion , medicinal chemistry , aqueous solution , organic chemistry , chromatography , physics , quantum mechanics
The kinetics and mechanism of Hg 2+ ‐catalyzed substitution of cyanide ion in an octahedral hexacyanoruthenate(II) complex by nitroso‐R‐salt have been studied spectrophotometrically at 525 nm ( λ max of the purple‐red–colored complex). The reaction conditions were: temperature = 45.0 ± 0.1°C, pH = 7.00 ± 0.02, and ionic strength (I) = 0.1 M (KCl). The reaction exhibited a first‐order dependence on [nitroso‐R‐salt] and a variable order dependence on [Ru(CN) 6 4− ]. The initial rates were obtained from slopes of absorbance versus time plots. The rate of reaction was found to initially increase linearly with [nitroso‐R‐salt], and finally decrease at [nitroso‐R‐salt] = 3.50 × 10 −4 M. The effects of variation of pH, ionic strength, concentration of catalyst, and temperature on the reaction rate were also studied and explained in detail. The values of k 2 and activation parameters for catalyzed reaction were found to be 7.68 × 10 −4 s −1 and E a = 49.56 ± 0.091 kJ mol −1 , Δ H ≠ = 46.91 ± 0.036 kJ mol −1 , Δ S ≠ = −234.13 ± 1.12 J K −1 mol −1 , respectively. These activation parameters along with other experimental observations supported the solvent assisted interchange dissociative (I d ) mechanism for the reaction. © 2008 Wiley Periodicals, Inc. Int J Chem Kinet 41: 215–226, 2009