ORGN 89

Bromonitrosulfolene undergoes the rearrangement and disproportionation reaction called the Halogen Dance under the unusually mild conditions. The reaction is DMSO concentration dependent, with the most rapid rate occurring in neat DMSO.  We report here the results of our transition state search along the multiple step ionization pathway predicted to be solvent dependent and therefore best fitting our experimental data.  We minimized structures along the reaction pathway from several trajectories until a maximum energy structure was found, and used this structure as the starting point for our transition state optimization and energy calculation.  The final energies for the key structures along the ionization pathway are compared to the previously studied intramolecular rearrangement pathway results and a mechanism for this unusual Halogen Dance reaction is proposed.