Browsing by Author "C. Mahapatra"

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Conformational Search and Spectroscopic Analysis of Biorelevant Molecule: 5-Chloro-2-hydroxy-N-isobutyl-3-oxo-2,3-dihydrobenzofuran-2-carboxamide
(Taylor and Francis Ltd., 2023) A.K. Vishwkarma; T. Yadav; G. Brahmachari; I. Karmakar; P. Yadav; S. Saha; C. Mahapatra; G.N. Pandey; C.S.P. Tripathi; P.K. Tripathi; V.K. Verma; A. Pathak
The present communication deals with the conformational, vibrational spectroscopic analysis and molecular docking study of an important biorelevant molecule namely 5-Chloro-2-hydroxy-N-isobutyl-3-oxo-2,3-dihydrobenzofuran-2-carboxamide. We have recorded FTIR spectrum of the target molecule in the spectral range of 4000–400 cm−1 and this has been correlated with simulated spectra of the most stable conformer. Most of the theoretical frequencies showed good agreement with experimental frequencies and a few were modified. The theoretical computations on the target molecule have been performed at well-known DFT/B3LYP level. The 6-31++G(d,p) was incorporated as a conventional basis set during the complete computations. For normal modes analysis, the potential energy distributions of the most stable conformer were calculated by Molvib program. The NBO calculations were performed to ensure stability of electronic structure and to explore intermolecular interactions. Some important thermodynamical parameters have also been investigated. The effect of aqueous media revealed that target molecule becomes slightly more stable in water phase. HOMO-LUMO gap has been computed to be 4.19 eV. © 2022 Taylor & Francis Group, LLC.
Molecular modeling, vibrational dynamics and NBO analysis of a synthetic bio‐relevant warfarin analog
(Elsevier B.V., 2023) T. Yadav; A.K. Vishwkarma; M. Mandal; I. Karmakar; A. Pathak; G. Brahmachari; P.K. Tripathi; A.K. Maddheshiya; N.P. Yadav; C. Mahapatra
We have performed the structural and spectroscopic analysis of a warfarin derivative (3-(1-(4-fluorophenyl)-3-(2-hydroxyphenyl)-3-oxopropyl)-4-hydroxy-2H-chromen-2-one). One-dimensional potential energy scanning (PES) of a warfarin derivative has been performed with the aim of finding low-lying energy conformations of this compound. During PES and other computations, we adopted DFT/B3LYP level along with the prevailing basis set 6-31++G(d,p). The conformational analysis through PES revealed five conformers and the global minima for conformer-4. The structures, IR and Raman spectra of conformers were deducted and the IR spectrum of the most stable conformer was correlated with the experimental FTIR spectrum of the target compound. The potential energy distributions (PEDs) for the most stable conformer was computed by employing the standard normal coordinate analysis (NCA) method in the input of Molvib program. Additionally, the HOMO/LUMO analysis and hyper-conjugative interaction energies of donor-acceptor interactions were calculated using NBO calculations. This conformational and vibrational spectroscopic investigation of the target molecule can be a crucial prerequisite for similar investigations on the target and its closely similar molecules. © 2023 Elsevier B.V.
Structural confirmation and spectroscopic signature of N-Allyl-2‑hydroxy-5-methyl-3-oxo-2, 3-dihydrobenzofuran-2-carboxamide and its monohydrate cluster
(Elsevier B.V., 2022) T. Yadav; A.K. Vishwkarma; G. Brahmachari; I. Karmakar; P. Yadav; S. Kumar; C. Mahapatra; J. Chowdhury; R. Kumar; G.N. Pandey; P.K. Tripathi; A. Pathak
We performed optimization of a bio-relevant molecule N-Allyl-2‑hydroxy-5-methyl-3-oxo-2, 3-dihydrobenzofuran-2-carboxamide and its monohydrate cluster in the isolated form. Potential energy scanning for the target molecule was carried out. Consequently, three stable conformers were obtained. The effect of interfusion of a water molecule on energy and vibrational modes of the target molecule was also investigated in the most stable conformer. The electronic structures and vibrational spectra of all the three conformers were computed. The FTIR spectrum of the target molecule was recorded at the spectral width of 4000–400cm−1 which was compared with the theoretically computed spectrum of the most stable conformer. We have computed Raman spectra of all the conformers. All theoretical calculations performed in this investigation were done at DFT/B3LYP level of theory. The standard normal coordinate analysis (NCA) method was used to calculate the potential energy distributions of normal modes of the target molecule and its monohydrate cluster. Moreover, the NBO calculations for the target molecule and its monohydrate cluster were done to determine electronic structures, bond energies, occupancies, HOMO-LUMO and hyper-conjugative interaction energies of donor-acceptor interactions. The enthalpy of formation showed that the formation of the monohydrated cluster is of an exothermic nature. © 2022 Elsevier B.V.
Theoretical spectroscopic signature of synephrine using DFT and the effect of hydrogen removal
(Taylor and Francis Ltd., 2022) N.P. Yadav; A.K. Vishwkarma; K. Kumar; A. Vats; A. Pathak; R. Kumar; V. Mukerjee; S. Moharana; T. Yadav; C. Mahapatra; S. Srivastava
The present work deals with the vibrational spectroscopic signature of the synephrine molecule and its radical in the gas phase. We have optimized synephrine and synephrine- in the ground state. The optimization of the neutral and de-protonated synephrine has been performed at the B3LYP/6-31++G(d, p) level of theory. The comparison of vibrational frequencies of both the structures has also been made. Most of the vibrational frequencies are in good agreement with the experimental ones. The effect of hydrogen removal from the site of oxygen atom upon geometrical parameters and vibrational frequencies of synephrine has been reported. Subsequently, the different thermodynamical parameters calculated at room temperature for the synephrine and its radical have been discussed. Interestingly, the enthalpy of formation for the synephrine and deprotonated synephrine has been calculated. The NBO analysis has been performed to check the stability of the electronic structure of the radical form of the synephrine molecule. Also, the HOMO-LUMO energy gap infers that synephrine is more reactive in its radical form. © 2022 Informa UK Limited, trading as Taylor & Francis Group.