The electronic structure of CH 2NCH 3, CH 2NNH 2, CH 2NOH and CH 2NF

Abstract

Ab initio geometry optimisation calculations have been carried out on CH 2NCH 3, CH 2NNH 2, CH 2NOH and CH 2NF using 6-31G and 6-31G** basis sets. Three of the four species possess a plane of symmetry while CH 2NNH 2 prefers a non-planar geometry with the amino N adopting sp 3 hybridisation. The CN bond length remains almost constant at 1.25 Å with an accompanying bond index of 2.2 for all four species. The CNR angle decreases and the related inversion energy at N increases as the R group becomes more electronegative. The charge on nitrogen decreases as the R group changes from CH 3 to F and the energy of protonation at N correspondingly decreases from 230 to 194 kcal mol −1. A slight positive charge is present on the imino carbon atoms and the stabilising energy of hydride ion addition to the imino carbon atom lies between 23.7 kcal mol −1 and 47.4 kcal mol −1.