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Đorđević S, Radenković S. Electronic structure, stability, and aromaticity of M 2B 6 (M = Mg, Ca, Sr, and Ba): an interplay between spin pairing and electron delocalization. Phys Chem Chem Phys 2022; 24:5833-5841. [PMID: 35225998 DOI: 10.1039/d1cp04791d] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
It has been shown in previous studies that the Be2B6 complex exhibits a triplet ground state with double aromaticity. In this work, the stability, electronic structure, and aromaticity of the homologous series M2B6 (M = Mg, Ca, Sr and Ba) were examined and compared to those of Be2B6. At the CCSD(T)/def2-TZVP//B3LYP/def2-TZVP level of theory, the target molecules were found to be more stable in the singlet than in the triplet spin state. Magnetically induced current densities and multicentre delocalization index (MCI) were employed to assess the aromatic character of the studied complexes. Both employed methods agree that M2B6 (M = Mg, Ca, Sr and Ba) are π aromatic and σ nonaromatic in the singlet ground state, and double aromatic in the triplet state. It was demonstrated that the electron counting rules of aromaticity cannot be used to correctly predict the aromaticity and relative stability of the examined molecules in different spin states.
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Affiliation(s)
- Slađana Đorđević
- University of Kragujevac, Faculty of Science, P. O. Box 60, 34000 Kragujevac, Serbia.
| | - Slavko Radenković
- University of Kragujevac, Faculty of Science, P. O. Box 60, 34000 Kragujevac, Serbia.
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Ariyarathna IR. Ground and Electronically Excited States of Main-Group-Metal-Doped B 20 Double Rings. J Phys Chem A 2021; 126:506-512. [PMID: 34939805 DOI: 10.1021/acs.jpca.1c08631] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Ab initio coupled-cluster, electron propagator, and Møller-Plesset second-order perturbation theory calculations are utilized to analyze the low-lying electronic states of several metal-doped B20. In the ground state, the presently focused AB20/EB20 (A = Li, Na, and K; E = Mg and Ca) consist of charge-separated A+B20-/E2+B202- frameworks. The excited electronic states of AB20 and EB20+ were analyzed by computing the vertical electron attachment energies (VEAEs) of AB20+ and EB202+. In several excited states, the radical electron is predominantly localized on the B20 frames, which are counterparts of the low-lying states of bare B20-. A variety of basis sets were tested on obtaining VEAEs, and the aug-cc-pVDZ/A,E d-aug-cc-pVDZ/B combination provided the best accuracy-efficiency compromise on them. Furthermore, this work analyzes the Rydberg-like excited states of AB20 and EB20+ and will serve as a guide for future studies on similar metal-doped boron systems.
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Affiliation(s)
- Isuru R Ariyarathna
- Department of Chemistry and Biochemistry, Auburn University, Auburn, Alabama 36849-5312, United States
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Buelna-García CE, Robles-Chaparro E, Parra-Arellano T, Quiroz-Castillo JM, del-Castillo-Castro T, Martínez-Guajardo G, Castillo-Quevedo C, de-León-Flores A, Anzueto-Sánchez G, Martin-del-Campo-Solis MF, Mendoza-Wilson AM, Vásquez-Espinal A, Cabellos JL. Theoretical Prediction of Structures, Vibrational Circular Dichroism, and Infrared Spectra of Chiral Be 4B 8 Cluster at Different Temperatures. Molecules 2021; 26:3953. [PMID: 34203563 PMCID: PMC8271876 DOI: 10.3390/molecules26133953] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 06/18/2021] [Accepted: 06/22/2021] [Indexed: 11/16/2022] Open
Abstract
Lowest-energy structures, the distribution of isomers, and their molecular properties depend significantly on geometry and temperature. Total energy computations using DFT methodology are typically carried out at a temperature of zero K; thereby, entropic contributions to the total energy are neglected, even though functional materials work at finite temperatures. In the present study, the probability of the occurrence of one particular Be4B8 isomer at temperature T is estimated by employing Gibbs free energy computed within the framework of quantum statistical mechanics and nanothermodynamics. To identify a list of all possible low-energy chiral and achiral structures, an exhaustive and efficient exploration of the potential/free energy surfaces is carried out using a multi-level multistep global genetic algorithm search coupled with DFT. In addition, we discuss the energetic ordering of structures computed at the DFT level against single-point energy calculations at the CCSD(T) level of theory. The total VCD/IR spectra as a function of temperature are computed using each isomer's probability of occurrence in a Boltzmann-weighted superposition of each isomer's spectrum. Additionally, we present chemical bonding analysis using the adaptive natural density partitioning method in the chiral putative global minimum. The transition state structures and the enantiomer-enantiomer and enantiomer-achiral activation energies as a function of temperature evidence that a change from an endergonic to an exergonic type of reaction occurs at a temperature of 739 K.
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Affiliation(s)
- Carlos Emiliano Buelna-García
- Departamento de Investigación en Polímeros y Materiales, Edificio 3G, Universidad de Sonora, Hermosillo 83000, Sonora, Mexico; (C.E.B.-G.); (J.M.Q.-C.); (T.d.-C.-C.)
- Organización Científica y Tecnológica del Desierto, Hermosillo 83150, Sonora, Mexico
| | - Eduardo Robles-Chaparro
- Departamento de Ciencias Químico Biologicas, Edificio 5A, Universidad de Sonora, Hermosillo 83000, Sonora, Mexico; (E.R.-C.); (T.P.-A.); (A.d.-L.-F.)
| | - Tristan Parra-Arellano
- Departamento de Ciencias Químico Biologicas, Edificio 5A, Universidad de Sonora, Hermosillo 83000, Sonora, Mexico; (E.R.-C.); (T.P.-A.); (A.d.-L.-F.)
| | - Jesus Manuel Quiroz-Castillo
- Departamento de Investigación en Polímeros y Materiales, Edificio 3G, Universidad de Sonora, Hermosillo 83000, Sonora, Mexico; (C.E.B.-G.); (J.M.Q.-C.); (T.d.-C.-C.)
| | - Teresa del-Castillo-Castro
- Departamento de Investigación en Polímeros y Materiales, Edificio 3G, Universidad de Sonora, Hermosillo 83000, Sonora, Mexico; (C.E.B.-G.); (J.M.Q.-C.); (T.d.-C.-C.)
| | - Gerardo Martínez-Guajardo
- Unidad Académica de Ciencias Químicas, Área de Ciencias de la Salud, Universidad Autónomade Zacatecas, Km. 6 Carretera Zacatecas-Guadalajara s/n, Ejido La Escondida C.P., Zacatecas 98160, Zac, Mexico;
| | - Cesar Castillo-Quevedo
- Departamento de Fundamentos del Conocimiento, Centro Universitario del Norte, Universidad de Guadalajara, Carretera Federal No. 23, Km. 191, C.P., Colotlán 46200, Jalisco, Mexico; (C.C.-Q.); (M.F.M.-d.-C.-S.)
| | - Aned de-León-Flores
- Departamento de Ciencias Químico Biologicas, Edificio 5A, Universidad de Sonora, Hermosillo 83000, Sonora, Mexico; (E.R.-C.); (T.P.-A.); (A.d.-L.-F.)
| | | | - Martha Fabiola Martin-del-Campo-Solis
- Departamento de Fundamentos del Conocimiento, Centro Universitario del Norte, Universidad de Guadalajara, Carretera Federal No. 23, Km. 191, C.P., Colotlán 46200, Jalisco, Mexico; (C.C.-Q.); (M.F.M.-d.-C.-S.)
| | - Ana Maria Mendoza-Wilson
- Coordinación de Tecnología de Alimentos de Origen Vegetal, CIAD, A.C., Carretera Gustavo Enrique Astiazarán Rosas, No. 46, Hermosillo 83304, Sonora, Mexico;
| | - Alejandro Vásquez-Espinal
- Computational and Theoretical Chemistry Group Departamento de Ciencias Químicas, Facultad de Ciencias Exactas, Universidad Andres Bello, Republica 498, Santiago 8370035, Chile;
| | - Jose Luis Cabellos
- Departamento de Investigación en Física, Edificio 3M, Universidad de Sonora, Hermosillo 83000, Sonora, Mexico
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