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Serrano-Sterling C, Becerra D, Portilla J, Rojas H, Macías M, Castillo JC. Synthesis, biological evaluation and X-ray crystallographic analysis of novel (E)-2-cyano-3-(het)arylacrylamides as potential anticancer agents. J Mol Struct 2021. [DOI: 10.1016/j.molstruc.2021.130944] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Bisong EA, Louis H, Unimuke TO, Odey JO, Ubana EI, Edim MM, Tizhe FT, Agwupuye JA, Utsu PM. Vibrational, electronic, spectroscopic properties, and NBO analysis of p-xylene, 3,6-difluoro-p-xylene, 3,6-dichloro-p-xylene and 3,6-dibromo-pxylene: DFT study. Heliyon 2020; 6:e05783. [PMID: 33385089 PMCID: PMC7772552 DOI: 10.1016/j.heliyon.2020.e05783] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 09/26/2020] [Accepted: 12/15/2020] [Indexed: 11/29/2022] Open
Abstract
This study explains the vibration and interaction of p-xylene and effect of three elements (fluorine, chlorine and bromine) of the halogen family substitution on it. Basic chemistry of four, compounds p-xylene (PX); 3,6-diflouro-p-xylene (DFPX); 3,6-dichloro-p-xylene (DCPX) and 3,6-dibromo-p-xylene (DBPX) has been explained extensively using theoretical approach. Vibrational energy distribution analysis (VEDA) software was used to study the potential energy distribution (PED) analysis, bond length, bond angles and dihedral angles of PX, DFPX, DCPX, DBPX after optimization with GAUSSIAN 09 software. The trend in chemical reactivity and stability of the studied compounds was observed to show increasing stability and decreasing reactivity moving from DBPX, DCPX, DFPX to PX and this was obtained from the calculated highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) values. Our results show that PX is the best electron donor (best nucleophile) while DBPX is the best electron acceptor (the best electrophile). We also observed that the substituted halogen increases the value of the bond angles but the effect is reduced as the size of the halogen increases. The maximum intensity and the frequency value for the maximum intensity of the different compounds was determined using the VEDA 04 software. From our natural bond orbital (NBO) 7.0 program analysis, the studied compounds are said to show biological activities as well as the intramolecular hyperconjugative interactions responsible for stabilizing the compounds. The NBO results also revealed that the non-bonding interaction existing between the lone pair electron on the halogen atoms and the aromatic ring increases the stability of the halogen substituted para-xylene molecules. Multiwfn: A Multifunctional Wavefunction Analyzer was used for the spectroscopic plots.
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Affiliation(s)
- Emmanuel A Bisong
- Department of Pure and Applied Chemistry, Faculty of Physical Sciences, University of Calabar, Calabar, Cross River State, Nigeria
| | - Hitler Louis
- Computational Quantum Chemistry Research Group, Department of Pure and Applied Chemistry, Faculty of Physical Sciences, University of Calabar, Calabar, Cross River State, Nigeria
| | - Tomsmith O Unimuke
- Department of Pure and Applied Chemistry, Faculty of Physical Sciences, University of Calabar, Calabar, Cross River State, Nigeria
| | - Joseph O Odey
- Department of Textile and Polymer Engineering, Ahmadu Bello University, Zaria, Nigeria
| | - Emmanuel I Ubana
- Department of Pure and Applied Chemistry, Faculty of Physical Sciences, University of Calabar, Calabar, Cross River State, Nigeria
| | - Moses M Edim
- Department of Chemistry, Cross River University of Technology, Calabar, Calabar, Cross River State, Nigeria
| | | | - John A Agwupuye
- Department of Pure and Applied Chemistry, Faculty of Physical Sciences, University of Calabar, Calabar, Cross River State, Nigeria.,Computational Quantum Chemistry Research Group, Department of Pure and Applied Chemistry, Faculty of Physical Sciences, University of Calabar, Calabar, Cross River State, Nigeria.,Department of Textile and Polymer Engineering, Ahmadu Bello University, Zaria, Nigeria.,Institute of Chemistry, Chinese Academy of Sciences, 10900 Beijing, China.,Department of Chemistry, Cross River University of Technology, Calabar, Calabar, Cross River State, Nigeria
| | - Patrick M Utsu
- Department of Pure and Applied Chemistry, Faculty of Physical Sciences, University of Calabar, Calabar, Cross River State, Nigeria
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Premkumar S, Jawahar A, Mathavan T, Kumara Dhas M, Sathe VG, Milton Franklin Benial A. DFT calculation and vibrational spectroscopic studies of 2-(tert-butoxycarbonyl (Boc) -amino)-5-bromopyridine. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2014; 129:74-83. [PMID: 24727165 DOI: 10.1016/j.saa.2014.02.147] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2013] [Revised: 02/16/2014] [Accepted: 02/21/2014] [Indexed: 06/03/2023]
Abstract
The molecular structure of 2-(tert-butoxycarbonyl (Boc) -amino)-5-bromopyridine (BABP) was optimized by the DFT/B3LYP method with 6-311G (d,p), 6-311++G (d,p) and cc-pVTZ basis sets using the Gaussian 09 program. The most stable optimized structure of the molecule was predicted by the DFT/B3LYP method with cc-pVTZ basis set. The vibrational frequencies, Mulliken atomic charge distribution, frontier molecular orbitals and thermodynamical parameters were calculated. These calculations were done at the ground state energy level of BABP without applying any constraint on the potential energy surface. The vibrational spectra were experimentally recorded using Fourier Transform-Infrared (FT-IR) and micro-Raman spectrometer. The computed vibrational frequencies were scaled by scale factors to yield a good agreement with observed experimental vibrational frequencies. The complete theoretically calculated and experimentally observed vibrational frequencies were assigned on the basis of Potential Energy Distribution (PED) calculation using the VEDA 4.0 program. The vibrational modes assignments were performed by using the animation option of GaussView 05 graphical interface for Gaussian program. The Mulliken atomic charge distribution was calculated for BABP molecule. The molecular reactivity and stability of BABP were also studied by frontier molecular orbitals (FMOs) analysis.
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Affiliation(s)
- S Premkumar
- Department of Physics, N.M.S.S.V.N. College, Madurai, 625 019 Tamilnadu, India
| | - A Jawahar
- Department of Chemistry, N.M.S.S.V.N. College, Madurai, 625 019 Tamilnadu, India
| | - T Mathavan
- Department of Physics, N.M.S.S.V.N. College, Madurai, 625 019 Tamilnadu, India
| | - M Kumara Dhas
- Department of Physics, N.M.S.S.V.N. College, Madurai, 625 019 Tamilnadu, India
| | - V G Sathe
- UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore 452 017, India
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