Spectroscopic [FT-IR and FT-Raman] and theoretical [UV–Visible and NMR] analysis on α-Methylstyrene by DFT calculations

Karthikeyan, N.; Prince, J. Joseph; Ramalingam, S.; Periandy, S.

doi:10.1016/j.saa.2015.02.015

Cited by 19 publications

(7 citation statements)

References 29 publications

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“…Electronegativity (χ) describes the ability of a molecule or functional group to attract electrons to itself. [ 47 ] The global electrophilicity index (ω) is a measure of the stability of the system after the extra electrons it receives from the environment. That is, when the molecules react, whether the molecule as an electrophile or a nucleophile will depend on the value of the electrophilic index.…”

Section: Resultsmentioning

confidence: 99%

Crystal structure analysis of (E)‐N‐(3,5‐dimethylphenyl)‐2‐(substituted benzylidene)thiosemicarbazone: Experimental and theoretical studies

Wang

Zhang

Fan

et al. 2020

J of Physical Organic Chem

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Two novel thiosemicarbazone derivatives (E)‐N‐(3,5‐dimethylphenyl)‐2‐(3‐methylbenzylidene)thiosemicar‐bazone (1) and (E)‐N‐(3,5‐dimethylphenyl)‐2‐(3‐fluorobenzylidene)thiosemicarbazone (2) had been synthesized and characterized by FT‐IR, nuclear magnetic resonance, and elemental analysis. Single crystal X‐ray diffraction analysis showed that compound 1 belongs to triclinic system in P‐1 space group and compound 2 belongs to monoclinic system in C2/c space group. It could be seen from the determined crystal structure that the central skeleton NNHC(S)NH of both thiosemicarbazone compounds have good planarity. Density functional theory (DFT) calculations were done using B3LYP/6‐31+G(d, p) basis set and the calculated results are in good agreement with the experimental data. In addition, the UV‐visible absorption spectrum was estimated based on TD‐DFT quantum chemistry calculations. Likewise, the simulated absorption spectrum is very consistent with the experimental data. Combining Hirshfeld surface analysis and molecular structure, it was found that the intermolecular hydrogen bond NH···SC constitutes central symmetric dimer . Through quantum chemical calculation, we investigated the reduced density gradient function and the independent gradient model, which provided a deeper insight into the intermolecular and intramolecular interaction force of the compounds. The frontier molecular orbital analysis and molecular electrostatic potential were also discussed by theoretical calculations.

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Section: Resultsmentioning

confidence: 99%

Crystal structure analysis of (E)‐N‐(3,5‐dimethylphenyl)‐2‐(substituted benzylidene)thiosemicarbazone: Experimental and theoretical studies

Wang

Zhang

Fan

et al. 2020

J of Physical Organic Chem

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“…[13] Furthermore, the head-to-tail link points easily becomes as cission points for polymer depolymerization. PAMS is the polymero fa lpha-methylstyrene( AMS) monomers, [14] where AMS is an alkene with an aromatic aliphatic hydrocarbon side chain. Therefore, the study of the depolymerization process of the head-to-tail configuration is essential to understand the depolymerization reaction.…”

Section: Introductionmentioning

confidence: 99%

“…[17] To systematically study the chemical-reaction processes,d ensity functional theory (DFT), as an effective first-principles method, has been widely used to explore the dissociation process of many organicm olecules, [18][19][20] and even to study the mechanism of polymer degradation. [14,[21][22][23] Hence, in this work, at heoretical study of the PAMS depolymerization mechanism, including the reaction potential energy surfaces, electronicstructurec haracteristics, and other aspects,i sc onducted by employing the DFT method.…”

Section: Introductionmentioning

confidence: 99%

“…[10,11] In this work, we investigate the depolymerization mechanism of chain-end scission based on at ypical poly(alpha-methylstyrene) (PAMS) model. PAMS is the polymero fa lpha-methylstyrene( AMS) monomers, [14] where AMS is an alkene with an aromatic aliphatic hydrocarbon side chain. Under ah igh temperaturea nd long illumination time, PAMS depolymerizes into AMS monomers with ay ield of up to 99 %, thus facilitatingt he effective recycling of AMS monomers.…”

Section: Introductionmentioning

confidence: 99%

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Depolymerization of Free‐Radical Polymers with Spin Migrations

Wang

Dai

et al. 2015

ChemPhysChem

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The mechanism of depolymerization is one of the most essential issues in chemical engineering and materials science. In this work, we investigate the depolymerization reactions of three typical free-radical poly(alpha-methylstyrene) tetramers by using first-principles density functional theory. The calculated results show that these reactions all need to overcome the energy barriers in the range of 0.58 to 0.77 eV, and that breaking the C-C bond at the chain end leads to the dissociation of alpha-methylstyrene monomers from the polymers. Electronic-structure analysis indicates that the reactions occur easily at the CR3 unsaturated end, and that the frontier molecular orbitals that participate in the reactions are mainly localized at the unsaturated ends. Meanwhile, spin population analysis presents the unique net spin-transfer process in free-radical depolymerization reactions. We hope the current findings can contribute to understanding the free-radical depolymerization mechanism and help guide future experiments.

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“…From optimized structure, the bond length, bond angle, dihedral angle are theoretically determined. The vibrational frequencies are determined and the frequencies are scaled by using 0.9684 for DFT(B3LYP)/6-311++G(d,p) [11]. The FTIR spectrum of ma2nba has been recorded in the region 450-4000 cm 1 on a Perkin Elmer system one FTIR spectrometer.…”

Section: Methodsmentioning

confidence: 99%

Molecular Interaction Studies between Methylamine and 2-Nitrobenzoic Acid by Quantum Chemical Calculation (FT-IR, FMO, GCRD, MEP, NLO) and Dielectric Relaxation Analysis

Aravinthraj¹,

Khan²,

Udayaseelan³

et al. 2019

IJSRPAS

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The FTIR spectrum of methylamine with 2-nitrobenzoic acid (ma2nba) in liquid phase is recorded and the comprehensive vibrational assignments and PED is attained by the vibrational energy distribution analysis. Ma2cba was theoretically optimized and FMO, nonlinear optical, molecular surfaces and comparison between Mulliken and natural charges were also performed by DFT method with B3LYP/6-311++G(d,p) basis set. The charge transfers in the molecule confirmed by the HOMO and lowest LUMO. Dielectric relaxation parameters like dielectric constant, dielectric loss, average and overall relaxation time, molar free energy of activation for viscous flow and the molar free energy of dielectric relaxation of ma2nba have been calculated over five different molar ratios (1:3, 1:2, 1:1, 2:1, 3:1) at room temperature by Higasi's method. These parameters are inferred in terms of molecular association and dipolar orientation. Moreover, the relaxation time found maximum at 1:1 molar ratio.

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Spectroscopic [FT-IR and FT-Raman] and theoretical [UV–Visible and NMR] analysis on α-Methylstyrene by DFT calculations

Cited by 19 publications

References 29 publications

Crystal structure analysis of (E)‐N‐(3,5‐dimethylphenyl)‐2‐(substituted benzylidene)thiosemicarbazone: Experimental and theoretical studies

Crystal structure analysis of (E)‐N‐(3,5‐dimethylphenyl)‐2‐(substituted benzylidene)thiosemicarbazone: Experimental and theoretical studies

Depolymerization of Free‐Radical Polymers with Spin Migrations

Molecular Interaction Studies between Methylamine and 2-Nitrobenzoic Acid by Quantum Chemical Calculation (FT-IR, FMO, GCRD, MEP, NLO) and Dielectric Relaxation Analysis

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