37903-93-8Relevant academic research and scientific papers
Identification of organophosphorus simulants for the development of next-generation detection technologies
Ellaby, Rebecca J.,Clark, Ewan R.,Allen, Nyasha,Taylor, Faith R.,Ng, Kendrick K. L.,Dimitrovski, Milan,Chu, Dominique F.,Mulvihill, Daniel P.,Hiscock, Jennifer R.
, p. 2008 - 2014 (2021)
Organophosphorus (OP) chemical warfare agents (CWAs) represent an ongoing threat but the understandable widespread prohibition of their use places limitations on the development of technologies to counter the effects of any OP CWA release. Herein, we describe new, accessible methods for the identification of appropriate molecular simulants to mimic the hydrogen bond accepting capacity of the PO moiety, common to every member of this class of CWAs. Using the predictive methodologies developed herein, we have identified OP CWA hydrogen bond acceptor simulants for soman and sarin. It is hoped that the effective use of these physical property specific simulants will aid future countermeasure developments.
Metal-Ion Catalysis in Nucleophilic Displacement Reactions at Carbon, Phosphorus, and Sulfur Centers. 5. Alkali-Metal Ion Catalysis and Inhibition in the Reaction of p-(Trifluoromethyl)phenyl Methanesulfonate with Ethoxide Ion
Pregel, Marko J.,Buncel, Erwin
, p. 5583 - 5588 (1991)
The reactions of alkali-metal ethoxides with p-(trifluoromethyl)phenyl methanesulfonate (1) in anhydrous ethanol at 25 deg C, yielding p-(trifluoromethyl)phenolate ion and ethyl methanesulfonate, have been investigated in order to reveal the effects of alkali-metal ions on reaction rates.Kinetic spectrophotometric studies of the nucleophilic displacement reaction of 1 with alkali-metal ethoxides in the absence and presence of complexing agents showed that the observed rate constants increase in the order LiOEt - + inhibits the reaction of ethoxide ion, while the other alkali-metal ions all act as catalysts.The kinetic data are analyzed in terms of parallel reactions of free ethoxide ion and alkali-metal ethoxide ion pairs, and rate constants for the reactions of these species are calculated.Association constants governing the interaction of the various metal ions with the transition state for the reaction of ethoxide ion with 1 are derived from the kinetic data and compared to association constants for interaction of metal ions with ethoxide ion in the ground state.The trend in the sizes of the association constants for the methanesulfonate transition state, Li+ + + +, is believed to arise from ion pairing of the transition state with solvated metal ions.A similar ordering is observed for the transition state in the reaction of p-nitrophenyl benzenesulfonate (2) with alkali metal ethoxides, while an inverted ordering is seen for the transition state for the reaction of ethoxides with p-nitrophenyl diphenylphosphinate (3).These results are interpreted in terms of the extent of charge delocalization in the transition states and its effect on interactions with bare or solvated metal ions.
Nucleophilic Displacement Reactions at Carbon, Phosphorus and Sulphur Centres: Reaction of Aryl Methanesulphonates with Ethoxide; Change in Mechanism with Change in Leaving Group
Pregel, Marko J.,Buncel, Erwin
, p. 307 - 311 (2007/10/02)
The reactions of ethoxide ion with aryl methanesulphonate esters (1a-c) in anhydrous ethanol at 25 deg C have been investigated in order to determine the effect of leaving group nucleofugality on the balance between substitution and elimination pathways.The reactions of p-nitrophenyl-(1a), m-nitrophenyl-(1b) and p-trifluoromethylphenyl-(1c) methanesulphonates have been examined by means of kinetic studies, sulphene trapping experiments, and deuterium exchange experiments.It is concluded that the para-nitro-substituted ester reacts predominantly by an E1cb-type elimination mechanism via a sulphene intermediate, with nucleophilic substitution as a minor concurrent pathway.Conversely, the meta-nitro-substituted ester reacts predominantly by substitution, with elimination as a minor concurrent pathway.The evidence available indicates that the para-trifluoromethyl-substituted ester reacts solely by substitution.Thus, the mechanism of reaction changes from nucleophilic substitution to elimination-addition as leaving group nucleofugality increases.
