PROTONATED NF3O - A G2MS THEORETICAL-STUDY ON THE STRUCTURE, STABILITY, AND INTERCONVERSION OF THE (NF3O)H+ ISOMERS

The protonation of NF3O has been investigated by DFT and high-level of theory ab initio calculations. The geometries of the (NF3O)H+ isomers and their interconnecting transition structures have been optimized a t the B3LYP/6-31G(d) level of theory and their relative stability and thermochemistry have been evaluated using the G2MS computational proce dure. The fluorine-protonated isomer la must be viewed as an ion-dipol e complex between NF2O+ and HF. It is more stable than the oxygen-prot onated isomer 2a by 32.4 kcal mol(-1). The proton affinity of NF3O and the enthalpy of formation of la are calculated as 172.0 and 154.7 kca l mol(-1), respectively. Both la and 2a are stable with respect to the ir dissociation products and their interconnecting transition structur e 3 lies 77.6 kcal mol(-1) above that of la. Therefore, both la and 2a should in principle be observable as distinguishable isomers in the g as phase. The present G2MS theoretical results have been compared with those concerning the strictly related (NF3)H+ isomers. (C) 1998 Elsev ier Science B.V. All rights reserved.