Theoretical proton affinity and fluoride affinity of nerve agent VX.
Proton affinity and fluoride affinity of nerve agent VX at all of its possible sites were calculated at the RI-MP2/cc-pVTZ//B3LYP/6-31G* and RI-MP2/aug-cc-pVTZ//B3LYP/6-31+G* levels, respectively. The protonation leads to various unique structures, with H(+) attached to oxygen, nitrogen, and sulfur atoms; among which the nitrogen site possesses the highest proton affinity of -ΔE ∼ 251 kcal/mol, suggesting that this is likely to be the major product. In addition some H(2), CH(4) dissociation as well as destruction channels have been found, among which the CH(4) + [Et-O-P(═O)(Me)-S-(CH(2))(2)-N(+)(iPr)═CHMe] product and the destruction product forming Et-O-P(═O)(Me)-SMe + CH(2)═N(+)(iPr)(2) are only 9 kcal/mol less stable than the most stable N-protonated product. For fluoridization, the S-P destruction channel to give Et-O-P(═O)(Me)(F) + [S-(CH(2))(2)-N-(iPr)(2)](-) is energetically the most favorable, with a fluoride affinity of -ΔE ∼ 44 kcal. Various F(-) ion-molecule complexes are also found, with the one having F(-) interacting with two hydrogen atoms in different alkyl groups to be only 9 kcal/mol higher than the above destruction product. These results suggest VX behaves quite differently from surrogate systems.
Cherry L. Emerson Center for Scientific Computation and Department of Chemistry, Emory University, Atlanta, Georgia 30322, United States.
Narayan C
NC
Bera
Satoshi
S
Maeda
Keiji
K
Morokuma
Al A
AA
Viggiano
D002619:Chemical Warfare Agents / Q000737:chemistry*; D005459:Fluorides / Q000737:chemistry*; D013058:Mass Spectrometry; D008697:Methane / Q000737:chemistry; D008958:Models, Molecular; D008968:Molecular Conformation; D009946:Organothiophosphorus Compounds / Q000737:chemistry*; D011522:Protons; D011789:Quantum Theory
D002619:Chemical Warfare Agents; D005459:Fluorides; D008697:Methane; D009946:Organothiophosphorus Compounds; D011522:Protons; C009680:VX-agent