ISSN:
0192-8651
Keywords:
ab initio
;
density functional theory
;
oxidation reactions
;
dioxiranes
;
carbonyl oxides
;
Chemistry
;
Theoretical, Physical and Computational Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
,
Computer Science
Notes:
The relative reactivity of a series of nucleophiles that includes ethylene, sulfides, sulfoxides, amines, and phosphines toward dioxirane, dimethyldioxirane, carbonyloxide and dimethylcarbonyloxide has been examined at the MP4/6-31G*//MP2/6-31G*, QCISD(T)/6-31G*//MP2/6-31G*, and B3-LYP/6-31G* levels of theory. The barriers for the oxidations with dimethyldioxirane are higher (up to 2.5 kcal/mol for the oxidation of H2S) than those for the oxidations with the parent dioxirane. The oxidation barriers for dioxirane are larger than those for the oxidations with peroxyformic acid, except the barriers for the oxidation of sulfoxides. The reactivity of dimethylsulfide toward dimethyldioxirane was found to be comparable to that of dimethylsulfoxide both in the gas phase and in solution (chloroform). The classical gas phase barrier for the oxidation of trimethylamine to trimethylamine oxide was higher (6.3 kcal/mol at the MP4//MP2/6-31G* level) than that for oxygen atom transfer to trimethylphosphine. When the transition states were examined by self-consistent reaction field (SCRF) methods, the predicted barriers for the oxidation of amines and phosphines were found to be in good agreement with experiment. The general trend in reactivity for oxidation by dioxirane was R2S≈R2SO, R3P〉R3N in the gas phase, and R2S≈R2SO, R3N≈R3P (R=Me) in solution. The oxidation barriers calculated using the B3-LYP functional were lower than those computed at the MP4 and QCISD(T) levels. © 1998 John Wiley & Sons, Inc. J Comput Chem 19: 1353-1369, 1998
Additional Material:
13 Ill.
Type of Medium:
Electronic Resource
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