Computational study on nature of transition structure for oxygen transfer from dioxirane and carbonyloxide

The relative reactivity of a series of nucleophiles that includes ethylene, sulfides, sulfoxides, amines, and phosphines toward dioxirane, dimethyldioxirane, carbonyloxide and dimethylcarbonyloxide has been U U Ž . U examined at the MP4r6-31G rrMP2r6-31G , QCISD T r6-31G rrMP2r631G , and B3-LYPr6-31G levels of theory. The barriers for the oxidations with Ž . dimethyldioxirane are higher up to 2.5 kcalrmol for the oxidation of H S than 2 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 Ž . dimethylsulfoxide both in the gas phase and in solution chloroform . The classical gas phase barrier for the oxidation of trimethylamine to trimethylamine Ž U . oxide was higher 6.3 kcalrmol at the MP4rrMP2r6-31G level than that for oxygen atom transfer to trimethylphosphine. When the transition states were Ž . 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 Ž R S f R SO, R P ) R N in the gas phase, and R S f R SO, R N f R P R s 2 2 3 3 2 2 3 3 Correspondence to: R. D. Bach; www:http:rrwww.udel.edur chemrbach Contractrgrant sponsor: National Science Foundation; contract grant numbers: CHE-96216 This article includes Supplementary Material available from the authors upon request or via the Internet at ftp.wiley.comr publicr journalsr jccr suppmatr 19r1353 or http:rr journals. wiley.comrjccr ( ) Journal of Computational Chemistry, Vol. 19, No. 12, 1353]1369 1998 Q 1998 John Wiley & Sons, Inc. CCC 0192-8651 / 98 / 121353-17