Ab Initio Study of the Reactions Between a Series of Substituted Singlet Nitrenium Ions and Water

Published

October 12, 2021

Author(s)

A A. Restrepo-Cossio, M Marquez, F Mari, Carlos A. Gonzalez

Abstract

Highly correlated ab initio molecular orbital calculations have been used to study the energetics and mechanisms governing the reactions of a series of substituted singlet nitrenium ions (¹[R-N-H]⁺, R=H, Cl, F, CN and Me) and water in gas phase and in solution. It was found that in gas phase and solution the nitrenium ions react in a barrierless fashion to produce an ylide-like intermediate [HNR OH₂]⁺, which in turn undergoes a 1,2-hydrogen shift to produce the corresponding protonated hydroxylamine [RNH₂OH]⁺ . Results obtained at the OCISD(T)/6-311++G**//QCISD/6-311++G** level indicated that in the gas phase, the intermediates are located between 27.7 kJ/mol and 339.6 kJ/mol below the reactants depending upon the substituent on the nitrenium ion. The transition states are located between 93.1 kJ/mol and 141.9 kJ/mol above the intermediates depending upon the substituent in question. In the presence of solvent, the intrinsic barrier of the process increases, as it lowers the relative energy of the ylide-like intermediates (and reactants) with respect to the transition state. It is also found that the reaction of water with the methyl nitrenium ion inhibits the decomposition of this species in gas phase. The effects of the substituent, the solvent and the levels of theory employed on the reaction paths are discussed in detail.

Citation

Journal of Physical Chemistry

Pub Type

Journals

Keywords

ab initio, azocations, carcinogen, solvent effects

Citation

Restrepo-Cossio, A. , Marquez, M. , Mari, F. and Gonzalez, C. (2021), Ab Initio Study of the Reactions Between a Series of Substituted Singlet Nitrenium Ions and Water, Journal of Physical Chemistry (Accessed April 23, 2024)