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Kinetics and mechanism of reaction of trans ‐(diaqua)(N,N′‐ethylene‐ bis ‐salicylidenimine) chromium(iii) with sulfur(iv): The labilizing effect of coordinated sulfite
Author(s) -
Dash Anadi C.,
Acharya Achyuta N.,
Mohanty Prakash,
Das Arabinda
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)30:5<373::aid-kin8>3.0.co;2-p
Subject(s) - chemistry , sulfite , pyridine , medicinal chemistry , imidazole , chromium , reaction mechanism , aqueous solution , rate determining step , stereochemistry , catalysis , inorganic chemistry , organic chemistry
The reaction of trans ‐[Cr(Salen)(OH 2 ) 2 ] + with aqueous sulfite yields trans ‐[Cr(Salen)(OH 2 )(OSO 2 (SINGLEBOND)O)] − (O‐bonded isomer). The rate and activation parameter data for the formation of the sulfito complex are consistent with a mechanism involving rate‐limiting addition of SO 2 to the Cr III (SINGLEBOND)OH bond. The complex ions, trans ‐[(OH 2 )Cr(Salen)(OSO 2 (SINGLEBOND)O)] − , and trans ‐[(OH)Cr(Salen)(OSO 2 (SINGLEBOND)O)] 2− , undergo reversible anation by NCS − , N 3 − , imidazole, and pyridine resulting in the formation of trans ‐[XCr(Salen)(OSO 2 (SINGLEBOND)O)] (N+1)− ( n =1 for X=N 3 − ,NCS − , and 0 for X=imidazole and pyridine) predominantly via dissociative interchange mechanism. The labilizing action of the coordinated sulfite on the trans ‐Cr III ‐X bond in trans ‐[XCr(Salen)(OSO 2 )] (n+1)− follows the sequence: NCS − pyridine ca. N 3 − ca. imidazole. Data analysis indicated that the coordinated sulfite has little trans activating influence. © 1998 John Wiley & Sons, Inc. Int J Chem Kinet 30: 373–384, 1998