18th Annual Student Research Conference
Science
Ab Inito Molecular Orbital and Density Functional Studies on the Solvolysis of Sarin and O,S-dimethyl methylphosphonothioate, a VX-like Compound
Jessica L. Menke*, Jolita Seckute, and Ryan J. Emnett
Dr. Eric V. Patterson, Faculty Mentor
Possible detoxification reactions of Sarin and a VX-like compound (O,S-dimethyl methyphosphonothioate) have been studied using computational chemistry. The potential energy surfaces for the hydrolysis of both compounds and the perhydrolysis of the VX-like compund have been computed at the MP2/6-31-G*//BLYP/MIDI! level of theory. Solvation effects have been taken into account through the use of the integral equation formalism polarizable contiuum model (IEF-PCM), at the BLYP/MIDI! level. The calculated results for the enthalpy of activation for the alkaline hydrolysis of Sarin agree with the experimental results. For the VX-like compound, results for the hydrolysis reaction show that the P-O and P-S bond cleavage processes are kinetically competitive, but that P-S bond cleavage is thermodynamically favored. For the perhydrolysis reaction, P-O cleavage cannot compete with P-S bond cleavage. In all cases, the data support initial formation of trigonal bipyramidal intermediates. The reaction of O,S-dimethyl methyphosphonothioate with ethoxide will also be discussed.
Keywords: VX, Sarin, Nerve agents, Computational chem
Topic(s):Chemistry
Presentation Type: Oral Paper
Session: 54-3
Location: VH 1010
Time: 4:15