Relative stability of onium states of nitrogen, oxygen, sulfur, and selenium atoms in cations formed in the elimination processes

• Published in: Russian chemical bulletin Vol. 58; no. 7; pp. 1338 - 1341
• Main Authors: Belen’kii, L. I., Nesterov, I. D., Chuvylkin, N. D.
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01.07.2009
• Subjects: Chemistry; Chemistry and Materials Science; Chemistry/Food Science; Full Articles; Inorganic Chemistry; Organic Chemistry; quantum chemical calculations; relative stability of onium states of nitrogen; and chlorine atoms; chalcogen; and DFT methods
• ISSN: 1066-5285; 1573-9171
• DOI: 10.1007/s11172-009-0178-0

Using the HF, B3LYP, and MP2 methods in the 6−31+G(d) basis with zero-point energy corrections, quantum chemical calculations of energy characteristics were carried out for the model molecules CH 2 =XH + (X = NH, O, S, Se) formed from the molecules YCH 2 XH (Y = NH 2 , OH, SH, SeH, Cl) either through the elimination of Y-anions or as a result of the abstraction of neutral species YH from these molecules upon their interaction with a proton. Stabilities of the onium states of nitrogen atom were shown to be considerably higher than those of the onium states of chalcogen derivatives, with the lowest stability shown by the models with the Cl atom being in the onium state. The results have been formulated in the form of stability series of the onium compounds and allowed one to interpret certain features of the aminomethylation reaction (the Mannich reaction), hydroxy- and alkoxymethylation, thio- and selenomethylation, and chloromethylation (the Blanc reaction).