Table 2.
Studies modeling various A-series agents´ properties
| Authors | A-series agent | Modeled properties | Outcomes |
|---|---|---|---|
| Franca et al. (2019) | A-230, A-232, A-234 | logP | Strong lipophilic character |
| Carlsen (2019) | A-230, A-232, A-234, A-242, A-262 | Vapor pressure, hydrolysis | Agents A-230, A-232, and A-234 have higher vapor pressures, while A-242 and A-262 possess lower vapor pressures than VX. All agents are defined with slow hydrolysis and biodegradation |
| Lyagin and Efremenko (2019) | A-232 | Enzyme-catalyzed hydrolysis | Organophosphate hydrolase may degrade the agent |
| Bhakhoa et al. (2019) | A-234 | Molecular, electronic, spectroscopic, thermodynamic properties, potential thermal, and hydrolysis degradation | Enthalpy and energy changes in hydrolysis and solvolysis of A-234. The electropositive charge on the phosphorus atom (P4) and the hybridized carbon atom (sp2) suggest two possible hydrolytic pathways. Higher probability for the carbon atom |
| Tan et al. (2019) | A-232 | Electronic properties, vibrational spectra | Ultra-sensitive detection of the novel agent A-232 by vibrational spectroscopy |
| De Farias (2019) | A-234 | Molecular, electronic properties | Both substances exhibit a smaller number of conformers and a higher dipole moment compared to VX. That explains why these substances are as toxic as VX |
| Nakano et al. (2019) | A-230, A-232, A-234 | Absorption spectra of neutral specie and singly charged ion | The A-series molecules can be ionized. The wavelengths for the first excited energy, the ionization energy, and the half-ionization energy have been calculated |
| Imrit et al. (2020) | A-234 | Hydrolysis and fragmentation | Possible hydrolysis of side chains under neutral conditions. Substitution attack by a water molecule on the acetamidine branch is thermodynamically more efficient than substitution on the central phosphorus of the molecule |
| Motlagh et al. (2020) | A-234 | Electronic properties, adsorption energies, fullerene capacity | The adsorption energies of A-234 are very high. A suitable nanosensor base for detecting the A-234 complex of C20 fullerene molecule (C20HNH2) |
| Yar et al. (2021) | A-230, A-232, A-234 | Adsorption and electronic properties of analytes on the carbon nitride 2-D (C2N) surface | Prediction of interaction between analytes and C2N surface for electrochemical detection |
| Otsuka and Miyaguchi (2021) | A-230, A-232, A-234 | Hydrolysis and fragmentation | A-230 is more easily hydrolyzed than A-232 and A-234. A-series agents are similar to VX but more hydrolysis-resistant than GB under basic conditions, which is better than neutral conditions for efficient decontamination. The activation energy of A-234 hydrolysis under alkaline conditions is smaller than all others. Fluorine release occurs more quickly than acetamide release in A-agents |
| Vieira et al. (2021) | A-230, A-232, A-242, A-262 | Structural, electronic, and thermodynamic properties, spectroscopic parameters | A-series molecules have two electropositive centers. LogP values confirm high lipophilicity (but less than VX). The central phosphorus atom (P4) is more positively charged than the hybridized carbon atom (sp2). Therefore, they preferentially accept electrons in the chemical reaction and form a bond with the nucleophile SN2 |
| Chernicharo et al. (2021) | A-230, A-232, A-234 | Comprehensive analysis of fragmentation pathways | The expected secondary fragmentations have been identified, such as the elimination of fluorine on the phosphorus atom and the formation of the acetamidine chain |
| Sajid et al. (2021) | A-230, A-232, A-234 | Electronic properties, adsorption energies | Stability of A-agents and graphdiyne complexes (GDY). The adsorption energy of A-234-GDY > A-232–GDY > A-230-GDY |
| Eskandari et al. (2022) | A-230, A-232, A-234, and other analogs | Structural, electronic, and thermodynamic properties, retention, and electrophilicity indices | The central phosphorus atom is more positive and thus reacts with the nucleophile SN2. Measured mass fragmentation pathways. Simulated IR and NMR data of agents A-230 and A-232 |
| Jeong et al. (2022a) | A-230, A-232, A-234 | Kappa, molecular weight, hydrogen bond acceptor, the complexity of bonding and distribution of heteroatoms, hydrogen bond donor, TPSA, logP, vapor pressure | Provided calculated values of the mentioned parameters, with logP confirming the highest lipophilicity of A-234 |
| Kim et al. (2022) | A-230, A-232, A-234 | Spectroscopic parameters (IR spectra) | Predicted high-accuracy IR spectra of A three A-series agents |
| Jeong et al. (2022b) | A-232, A-234 | Nuclear magnetic resonance spectra | 1H and 13C NMR prediction for 83 A-series candidates, which were experimentally confirmed for A-232 and A-234 |
| Rashid et al. (2023) | A-230, A-232, A-234 | Electronic structures properties (electrophilicity index) and hydrolysis rate | The hydrolysis rate of A-series is lower than that of V-series nerve paralyzers and significantly lower than that of G-series. They compared the experimental hydrolysis rate data with the prediction hydrolysis rate data calculated using the electrophilic index. The trend of the hydrolysis rate between A-230 > A-232 > A-234 corresponded with the lipophilicity of molecule A-234 > A-232 > A-230 |
| Noga et al. (2023a) | A-230, A-232, A-234, A-242, A-262 | Hydrolysis and biodegradation | Evaluation of hydrolysis estimates showed extremely rapid degradation of compounds A-230 and A-242 in contrast to A-232, A-234, and A-262 |
| ChemSpider (b, 2018c, 2018a) | A-230, A-232, A-234 | Density, boiling point, vapor pressure, enthalpy, flash point, etc. | Predicted by ACD/Labs ChemAxon |
Means of modeling: Franca et al. (2019)—chemicalize.com; Carlsen et al. (2019)—QSAR modeling; Lyagin and Efremenko (2019)—molecular docking; Bhakhoa et al. (2019)—DFT; Tan et al. (2019)—DFT; De Farias (2019)—SE method; Nakano et al. (2019)—DFT; Imrit et al. (2020)—DFT; Motlagh et al. (2020)—DFT; Yar et al. (2021)—DFT; Otsuka and Miyaguchi (2021)—DFT; Vieira et al. (2021)—DFT, QSAR modeling; Chernicharo et al. (2021)—DFT; Sajid et al. (2021)—DFT; Eskandari et al. (2022)—DFT; Jeong et al. (2022a)—DFT, QSAR modeling; Kim et al. (2022)—DFT; Jeong et al. (2022b)—DFT; Rashid et al. (2023)—DFT; Noga et al. (2023a, b)—QSAR modeling
DFT density functional theory, SE semiempirical, QSAR quantitative structure–activity relationship, n/a not available