Browsing by Author "N.P. Yadav"

Now showing 1 - 5 of 5

Conformational and vibrational spectroscopic investigation of N-n‑butyl, S-2-nitro-1-(p-tolyl)ethyl dithiocarbamate – a bio-relevant sulfur molecule
(Elsevier B.V., 2021) T. Yadav; G. Brahmachari; I. Karmakar; P. Yadav; A.K. Prasad; A. Pathak; A. Agarwal; R. Kumar; V. Mukherjee; G.N. Pandey; R.R.F. Bento; N.P. Yadav
This work describes the synthesis, conformational, thermodynamics and vibrational spectroscopic studies of N-n‑butyl, S-2-nitro-1-(p-tolyl)ethyl dithiocarbamate, a bio-relevant sulfur molecule. A total of seven low lying energy structures of N-n‑butyl, S-2-nitro-1-(p-tolyl)ethyl dithiocarbamate are theoretically predicted. The quantum chemical calculations were performed using Gaussian09 with the 6–31++G(d,p) basis set. This basis set has been shown to reproduce the experimental structural and vibrational properties of N-n‑butyl, S-2-nitro-1-(p-tolyl)ethyl dithiocarbamate. The infrared spectrum was recorded from sample in Kbr pellet in the range 400 to 4000cm−1 with a spectral resolution of 4cm−1and this correlates well with the theoretical spectra of the most stable conformer. The potential energy distribution of the most stable conformer was calculated by employing the normal coordinate analysis method. The natural bond orbital analysis (NBO) of the most stable conformer was done to study the donor-acceptor interactions and stability of the electronic structure. The different thermodynamical parameters, viz, entropy, specific heat, free and thermal energy are also estimated and discussed. The frontier bond orbital analysis has been studied to explore the transition profile of the molecule. Moreover, the structure-property relationship and molecular docking study with methyltransferase group of enzymes have been performed. © 2021 Elsevier B.V.
Enhanced dielectric and electrical properties of polystyrene-2% divinyl benzene (PDB) embedded in SrTiO3-Poly (vinylidene fluoride) three phase composite films
(Elsevier GmbH, 2022) N.P. Yadav; Bibhuti B. Sahu; Tarun Yadav; Rajneesh Kumar; Amit Pathak; G.N. Pandey; Srikanta Moharana
A facile solution casting technique has been employed to fabricate ceramic SrTiO3; STO particle and polystyrene-2% divinyl benzene (PDB) filled three phase composite films using poly(vinylidene fluoride) (PVDF) matrix. The frequency dependence of dielectric and electrical properties of the three phase PVDF-STO-PDB composite films of various weight percentage of PDB (fPDB) were analyzed. With the small change in the AC conductivity and dielectric loss the dielectric constant of the PVDF-STO-PDB composite systems is improved noticeably. The experimental results suggested that, the introduction of 10 wt% of PDB particles in the PVDF-STO composites enhanced the dielectric constant (≈76) and suppressed dielectric loss value (< 0.5) at 100 Hz. This may be attributed to the addition of PDB particles improved the establishment of polarization. The morphological analysis depicts that the PDB particles are uniformly dispersed and well compatibility between filler particles and polymer matrix which may be ascribed to the minimization of dielectric loss of the resultant composites. Further, the strong interaction between PDB particles and PVDF matrix at the interface is the crucial factor in the improvement of the dielectric and electrical properties. The percolation theory was used to elucidate the dielectric and electrical performance of PVDF-STO-PDB composites. It is noticed that the three phase PVDF-STO-PDB composite films exhibited an insulator-conductor transition with percolation threshold of fPDB = 5 wt%. The three phase composites with high dielectric constant (≈76) at percolation threshold might be helpful to understand the influence of PDB particles on the interfaces between the ceramics and polymer matrix. This work will provide an easy and effective solution to fabricate high performance three phase composites to the development of high energy storage applications. © 2022 Elsevier GmbH
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.
Superior dielectric and electrical characteristics of poly(methylmethacrylate) (PMMA)-BiFeO3-Polystyrene-2% divinyl benzene (PDB) composites
(Elsevier GmbH, 2023) N.P. Yadav; Bibhuti B. Sahu; R.N. Mahaling; Tarun Yadav; Pankaj K. Tripathi; Srikanta Moharana
An extraordinarily high dielectric constant and low dielectric loss PMMA-BFO-PDB composite material was developed by mixing poly(methylmethacrylate) (PMMA) as the polymer matrix, bismuth ferrite (BFO), and polystyrene 2% divinyl benzene (PDB) as fillers using the solution casting process. The surface morphology analysis demonstrations the PDB particle uniformly dispersed in the PMMA matrix. The frequency dependent dielectric and electrical characteristics of the PMMA-BFO-PDB composite films on various weight percentages of PDB contents and wide range of frequency at room temperature were investigated. It is observed that the maximum dielectric constant of the PMMA-BFO-PDB composites was achieved around ≈ 108 and similarly dielectric loss factor of just about ≈ 1 for 20 wt% of PDB contents at 102 Hz. In addition, the PMMA-BFO-PDB composite achieved a dielectric constant of 108 at 102 Hz, which is 21 times higher than that of the pure PMMA matrix. PMMA-BFO-PDB composite films may be used as a high performance dielectric in future energy storage devices, such as high storage capacitors. © 2023 Elsevier GmbH
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.