TY - DATA T1 - Computational Study of the Curtius-like Rearrangements of Phosphoryl, Phosphinyl, and Phosphinoyl Azides and Their Corresponding Nitrenes PY - 2007/12/07 AU - Ryan D. McCulla AU - Gamal A. Gohar AU - Christopher M. Hadad AU - Matthew S. Platz UR - https://acs.figshare.com/articles/journal_contribution/Computational_Study_of_the_Curtius_like_Rearrangements_of_Phosphoryl_Phosphinyl_and_Phosphinoyl_Azides_and_Their_Corresponding_Nitrenes/2969887 DO - 10.1021/jo0711687.s002 L4 - https://ndownloader.figshare.com/files/4669132 KW - phosphorylnitrene KW - mol KW - photoaffinity labels KW - activation KW - rearrangement KW - dimethylphosphinyl KW - CASSCF KW - triplet KW - nitrene KW - kcal KW - dimethylphosphorylnitrene KW - energy singlet state KW - weaponized organophosphorus compounds KW - 3LYP KW - dimethylphosphoryl azides N2 - The free energies of reaction (ΔG) and activation (ΔG⧧) were determined for the Curtius-like rearrangement of dimethylphosphinoyl, dimethylphosphinyl, and dimethylphosphoryl azides as well as the corresponding singlet and triplet nitrenes by CBS-QB3 and B3LYP computational methods. From CASSCF calculations, it was established that the closed-shell configuration was the lower energy singlet state for each of these nitrenes. The triplet states of dimethylphosphinyl- and dimethylphosphorylnitrene are the preferred ground states. However, the closed-shell singlet state is the ground state for dimethylphosphinoylnitrene. The CBS-QB3 ΔG⧧ values for the Curtius-like rearrangements of dimethylphosphinyl and dimethylphosphoryl azides were 45.4 and 47.0 kcal mol-1, respectively. For the closed-shell singlet dimethylphosphinyl- and dimethylphosphorylnitrene, the CBS-QB3 ΔG⧧ values for the rate-limiting step of the Curtius-like rearrangement were 22.9 and 18.0 kcal mol-1, respectively. It is unlikely that the nitrenes will undergo a Curtius-like rearrangement because of competing bimolecular reactions that have lower activation barriers. The pharmacology of weaponized organophosphorus compounds can be investigated using phosphorylnitrenes as photoaffinity labels. Dominant bimolecular reactivity is a desirable quality for a photoaffinity label to possess, and thus, the resistance of phosphorylnitrenes to intramolecular Curtius-like rearrangements increases their usefulness as photoaffinity labels. ER -