A quantum chemical study of the gas-phase homolytic S–Br bond dissociation enthalpies of sulfenyl bromides

Abstract

This study reports the gas-phase homolytic S–Br bond dissociation enthalpies (at 298 K) for a set of 44 sulfenyl bromide derivatives (RSBr) obtained using the high-level G4 thermochemical protocol. For the species in this set, we find that the BDEs range from 178.0 kJ mol^–1 (F3CSSBr) to 239.5 kJ mol^–1 (HC(=NH)SBr). We have additionally reported molecule and radical stabilization enthalpies for all species, allowing for insights to be gained as to the effect of substituents in both the sulfenyl bromide reactants and the sulfur-centered radical products. In addition, we have also reported the BDEs of six sufinyl bromides (RS(=O)Br) and six sulfonyl bromides (RSO₂Br). For the sulfinyl bromides, the BDEs range from 156.6 kJ mol^–1 (F₃CS(=O)Br) to 173.8 kJ mol^–1 (^tBuS(=O)Br), whilst for the sulfonyl bromides, the BDEs range from 211.0 kJ mol^–1 (F3CSO2Br) to 226.2 kJ mol^–1 (FSO₂Br).