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Del Angel Cruz D, Galvez Vallejo JL, Gordon MS. Analysis of the bonding in tetrahedrane and phosphorus-substituted tetrahedranes. Phys Chem Chem Phys 2023; 25:27276-27292. [PMID: 37791459 DOI: 10.1039/d3cp03619g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
The bonding structures of tetrahedrane, phosphatetrahedrane, diphosphatetrahedrane and triphosphatetrahedrane are studied by employing an intrinsic quasi-atomic orbital analysis. Ethane, cyclopropane and tetrahedral P4 are employed as reference systems. The orbital analysis is paired with the computation of strain energies via isodesmic reactions. The results show that the increase in geometric strain upon transition from ethane to cyclopropane to tetrahedrane weakens the CC bonds, despite leading to shorter C-C interatomic distances. With the increase in strain, the orbitals centered on C and involved in the bonding of the cage structure are observed to have elevated p-character, and the orbital structure of C deviates from sp3 hybridization. The systematic substitution of CH groups by P atoms in the cage structure of tetrahedrane leads to stronger CC bonds, larger angles in the cage structures of the resulting phosphatetrahedranes, lower p-character in the orbitals involved in the bonding of the cages, and lower strain energies. It is found that P is more amenable to strained molecular arrangements than is C, and that the propensity of a given atom to hybridize s and p functions, or the lack thereof, has implications in the stability of molecules with strained geometries. The combination of the calculations presented here with the existing literature provides insight into the apparent propensity of tetrahedrane and P4 to 'break' their tetrahedral structures. Trends in the bonding interactions, such as bond strengths, s- and p-orbital characters and charge transfer are identified and related to the strain energy observed in each of the analyzed systems.
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Affiliation(s)
| | - Jorge L Galvez Vallejo
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, USA.
- School of Computing, Australian National University, Canberra, ACT 2601, Australia
| | - Mark S Gordon
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, USA.
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Duarte JC, da Rocha RD, Borges I. Which molecular properties determine the impact sensitivity of an explosive? A machine learning quantitative investigation of nitroaromatic explosives. Phys Chem Chem Phys 2023; 25:6877-6890. [PMID: 36799468 DOI: 10.1039/d2cp05339j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
We decomposed density functional theory charge densities of 53 nitroaromatic molecules into atom-centered electric multipoles using the distributed multipole analysis that provides a detailed picture of the molecular electronic structure. Three electric multipoles, (the charge of the nitro groups), (the total dipole, i.e., polarization, of the nitro groups), (the total electron delocalization of the C ring atoms), and the number of explosophore groups (#NO2) were selected as features for a comprehensive machine learning (ML) investigation. The target property was the impact sensitivity h50 (cm) values quantified by drop-weight measurements, with a large h50 (e.g., 150 cm) indicating that an explosive is insensitive and vice versa. After a preliminary screening of 42 ML algorithms, four were selected based on the lowest root mean square errors: Extra Trees, Random Forests, Gradient Boosting, and AdaBoost. Compared to experimental data, the predicted h50 values of molecules having very different sensitivities for the four algorithms have differences in the range 19-28%. The most important properties for predicting h50 are the electron delocalization in the ring atoms and the polarization of the nitro groups with averaged weights of 39% and 35%, followed by the charge (16%) and number (10%) of nitro groups. A significant result is how the contribution of these properties to h50 depends on their actual sensitivities: for the most sensitive explosives (h50 up to ∼50 cm), the four properties contribute to reducing h50, and for intermediate ones (∼50 cm ≲ h50 ≲ 100 cm) #NO2 and contribute to increasing it and the other two properties to reducing it. For highly insensitive explosives (h50 ≳ 200 cm), all four properties essentially contribute to increasing it. These results furnish a consistent molecular basis of the sensitivities of known explosives that also can be used for developing safer new ones.
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Affiliation(s)
- Julio Cesar Duarte
- Departamento de Engenharia de Computação, Instituto Militar de Engenharia, Instituto Militar de Engenharia, Praça General Tibúrcio, 80, Urca, Rio de Janeiro (RJ), 22290-270, Brazil. .,Programa de Pós-Graduação em Engenharia de Defesa, Militar de Engenharia, Instituto Militar de Engenharia, Praça General Tibúrcio, 80, Urca, Rio de Janeiro (RJ), 22290-270, Brazil
| | - Romulo Dias da Rocha
- Programa de Pós-Graduação em Engenharia de Defesa, Militar de Engenharia, Instituto Militar de Engenharia, Praça General Tibúrcio, 80, Urca, Rio de Janeiro (RJ), 22290-270, Brazil
| | - Itamar Borges
- Departamento de Engenharia de Computação, Instituto Militar de Engenharia, Instituto Militar de Engenharia, Praça General Tibúrcio, 80, Urca, Rio de Janeiro (RJ), 22290-270, Brazil. .,Departamento de Química, Militar de Engenharia, Instituto Militar de Engenharia, Praça General Tibúrcio, 80, Urca, Rio de Janeiro (RJ), 22290-270, Brazil
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Green synthesis of BOSCHIBAs: Photo- and water stability, cytotoxicity assays, and theoretical calculations. J Mol Struct 2023. [DOI: 10.1016/j.molstruc.2022.134122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Zengel ER, Garcia JR, Goodrich DA, Bayse CA. Trigger bond analysis of azo‐based energetic materials. J PHYS ORG CHEM 2022. [DOI: 10.1002/poc.4330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Elizabeth R. Zengel
- Department of Chemistry and Biochemistry Old Dominion University Norfolk VA USA
| | - Jenna R. Garcia
- Department of Chemistry and Biochemistry Old Dominion University Norfolk VA USA
| | - Daja A. Goodrich
- Department of Chemistry and Biochemistry Old Dominion University Norfolk VA USA
| | - Craig A. Bayse
- Department of Chemistry and Biochemistry Old Dominion University Norfolk VA USA
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Song Q, Zhang L, Mo Z. Alleviating the stability–performance contradiction of cage-like high-energy-density materials by a backbone-collapse and branch-heterolysis competition mechanism. Phys Chem Chem Phys 2022; 24:19252-19262. [DOI: 10.1039/d2cp02061k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Key role of cage-like conformations in alleviating the stability–performance contradiction of HEDMs.
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Affiliation(s)
- Qingguan Song
- Institute of Applied Physics and Computational Mathematics, Beijing, 100088, China
- CAEP Software Center for High Performance Numerical Simulation, Beijing, 100088, China
- Institute of Chemical Materials, China Academy of Engineering Physics, Mianyang, 621999, China
| | - Lei Zhang
- Institute of Applied Physics and Computational Mathematics, Beijing, 100088, China
- CAEP Software Center for High Performance Numerical Simulation, Beijing, 100088, China
| | - Zeyao Mo
- Institute of Applied Physics and Computational Mathematics, Beijing, 100088, China
- CAEP Software Center for High Performance Numerical Simulation, Beijing, 100088, China
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Wen L, Yu T, Lai W, Shi J, Liu M, Liu Y, Wang B. Intra‐Ring
Bridging: A Strategy for Molecular Design of Highly Energetic Nitramines. CHINESE J CHEM 2021. [DOI: 10.1002/cjoc.202100190] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Linyuan Wen
- State Key Laboratory of Fluorine & Nitrogen Chemicals, Xi'an Modern Chemistry Research Institute, Xi'an Shaanxi 710065 China
- International Research Center for Renewable Energy, State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, Xi'an Shaanxi 710049 China
| | - Tao Yu
- State Key Laboratory of Fluorine & Nitrogen Chemicals, Xi'an Modern Chemistry Research Institute, Xi'an Shaanxi 710065 China
| | - Weipeng Lai
- State Key Laboratory of Fluorine & Nitrogen Chemicals, Xi'an Modern Chemistry Research Institute, Xi'an Shaanxi 710065 China
| | - Jinwen Shi
- International Research Center for Renewable Energy, State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, Xi'an Shaanxi 710049 China
| | - Maochang Liu
- International Research Center for Renewable Energy, State Key Laboratory of Multiphase Flow in Power Engineering, Xi'an Jiaotong University, Xi'an Shaanxi 710049 China
| | - Yingzhe Liu
- State Key Laboratory of Fluorine & Nitrogen Chemicals, Xi'an Modern Chemistry Research Institute, Xi'an Shaanxi 710065 China
| | - Bozhou Wang
- State Key Laboratory of Fluorine & Nitrogen Chemicals, Xi'an Modern Chemistry Research Institute, Xi'an Shaanxi 710065 China
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