Computational and experimental studies on dielectric relaxation and dipole moment of some anilines and phenol

Maridevarmath, C.V.; Malimath, G.H.

doi:10.1016/j.molliq.2017.06.059

Cited by 25 publications

(16 citation statements)

References 19 publications

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“…The Δ E * is used as a direct indicator of kinetic stability. A large Δ E * implies high kinetic stability and low chemical reactivity as it is energetically unfavorable to add electrons to a high‐lying LUMO or to extract electrons from a low‐lying HOMO . Combination of alkyl substituted N‐methyl pyrrolidinium cation (P yr 1R , R = C 1 to C 6 ) with four anions, BF 4 − , PF 6 − , TFSI − , and TFO − has been investigated in this work.…”

Section: Introductionmentioning

confidence: 99%

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Electronic structural studies of pyrrolidinium‐based ionic liquids for electrochemical application

Sivaji

Vijayalakshmi

George

2019

Int J of Quantum Chemistry

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Electrochemical stability and noncovalent interactions escorting the cyclic ammonium-based ionic liquids composed of N-alkyl-substituted N-methyl pyrrolidinium (P yr 1R) (R = methyl, ethyl, propyl, butyl, pentyl, hexyl) cations and four anions hexafluorophosphate (PF 6 ), tetrafluoroborate (BF 4 ), bis(trifluoromethylsulfonylimide (TFSI), and trifluoromethane sulfonate (TFO) have been analyzed using the density functional theory. Electronic structures, electrochemical window, frontier orbital energy difference (HOMO-LUMO gap), binding energies, vibrational spectra of these ion pairs were characterized. It has been established that ion pair formation is largely reigned by C HÁ Á ÁF interactions between anionic fluorine for BF 4 − and PF 6 − anions and C HÁ Á ÁO interactions between anionic oxygen for TFSI and TFO anions and pyrrolidinic proton, methyl, or alkyl group protons of the cations. The effect of alkyl chain length and pairing anions of the alkyl substituted N-methyl pyrrolidinium-based ionic liquids on the electrochemical window was investigated. The results revealed that the HOMO energy of pairing anions is the key factor to decide the electrochemical window. Further quantification of noncovalent interactions in terms of electrostatic and hydrogen bonding interactions has been brought out employing a novel method with the aid of Mulliken and Merz-Singh-Kollman charges, prevailed in pyrrolidinium-based ionic liquids. K E Y W O R D S density functional theory, electrochemical stability, HOMO-LUMO, hydrogen bonding, ionic liquid 1 | INTRODUCTION Room temperature (RT) ionic liquids (ILs) have gained considerable attention due to their unique properties such as low vapor pressure, high ionicconductivity, and wide electrochemical window and are promising candidates as electrolytes for electrochemical applications. [1,2] ILs has many energy applications such as battery technologies, [3][4][5][6][7] fuel cells, [8,9] dye sensitized solar cells, [10] thermo-electrochemical cells, [11] super capacitors, [12] actuators, [13] etc. Since the physicochemical and electrochemical properties of ILs depend on the structure of their constituent cations and anions, it is possible to tune these properties by choosing various combinations of anions and cations; this drawn the attention of researchers to design new materials for many different fields. Hence, ILs are recognized as designer solvents. [14] The synthesis and systematic thermophysical and electrochemical investigations by Neale and coworkers [15] on ethereal functionalized cyclic alkyl ammonium-based ILs established that these ILs are electrochemically more stable and are suitable for electrochemical devices such as battery systems, fuel cells, or super capacitors.

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Section: Introductionmentioning

confidence: 99%

“…A large ΔE* implies high kinetic stability and low chemical reactivity as it is energetically unfavorable to add electrons to a high-lying LUMO or to extract electrons from a low-lying HOMO. [27][28][29][30]…”

mentioning

confidence: 99%

Electronic structural studies of pyrrolidinium‐based ionic liquids for electrochemical application

Sivaji

Vijayalakshmi

George

2019

Int J of Quantum Chemistry

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“…For every viscous medium, the steady state viscosity (η s ) values were determined experimentally and the results are given in On the other hand, if the molecule is unsymmetrical in shape, then its rotation around at least one axis may involve the displacement of neighbouring molecules and the corresponding relaxation time (τ s ) will depend markedly upon the viscosity of the medium [28]. It is to be noted that in the present study, the molecules studied are being fairly spherical [29] relation between logτ s vs. logη s at higher viscosity values may be attributed to the dynamic nature of the viscosity (η d ) rather than the macroscopic steady state viscosity (η s ).…”

Section: Resultsmentioning

confidence: 97%

“…The assumption of linear dependence of viscosity with relaxation time irrespective of the size and shape of the surrounding molecules in Debye's theory was found to be valid in case of certain simple molecules which are surrounded by a medium of low viscosity. From the experimental results of different workers it is observed that, the results could be well explained in the case of certain simple molecules by using In view of the above, the dielectric relaxation studies in terms of viscosity have been carried out on pure samples of 2-Nitroaniline, 4-Bromoaniline, 4-Chloroaniline, 4-Chlorophenol and also on the binary mixture of (2-Nitroaniline + 4-Bromoaniline) in dilute solutions in different mixed solvents (benzene + paraffin) at room temperature and it is the continuation of our earlier research work [29].…”

Section: Introductionmentioning

confidence: 99%

Studies on dielectric relaxation in relation to viscosity of some anilines, phenol, and their binary mixtures at microwave frequencies

Maridevarmath

Malimath

2019

Can. J. Phys.

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In the present work, the study of variation of relaxation time (τ) with viscosity of the medium (η) is carried out on four polar samples: 2-Nitroaniline, 4-Bromoaniline, 4-Chloroaniline, 4-Chlorophenol, and also on the binary mixture of 2-Nitroaniline + 4-Bromoaniline at room temperature by using microwave bench operating at a frequency of 9.59 GHz. In this regard, the different parameters like dielectric constant ([Formula: see text]), dielectric loss ([Formula: see text]), relaxation time (τs), macroscopic steady state viscosity (ηs), dynamic viscosity (ηd), and viscoelastic relaxation time (τve) were determined for all the systems. It is observed that the relaxation time (τs) increases with the increase in the viscosity of the medium for all the systems. Plots of log(τs) versus log(ηs) for all the systems show that variation of relaxation time is found to be nonlinear in the higher viscosity regions. This suggests the failure of Debye’s theory at these regions. Further, the nonlinear behaviour of relaxation time with the viscosity is explained by using the viscoelastic model suggested by Barlow et al. (Proc. R. Soc. A 309, 473 (1969). doi: 10.1098/rspa.1969.0053 ). It is also observed that macroscopic steady state viscosity (ηs) values are greater than the dynamic viscosity (ηd), and viscoelastic relaxation time (τve) values were found to be lower compared to the relaxation time (τs). These results suggest that the effective frictional resistance experienced by the molecules during reorientation is lower and the measured values of macroscopic steady state viscosity (ηs) are frequency dependent.

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“…Such efficiency of ethanol to other solvents (Figure 1) may be related to the dielectric constant due to the greater dipole-dipole interaction necessary to cyclocondensation reaction and products obtention. 25 In addition, the column purifications or recrystallization were not required, avoiding the excessive expenditure of solvents. Moreover, the application of microwave irradiation avoided excessive reaction times and high temperatures.…”

Section: Resultsmentioning

confidence: 99%

Microwave Assisted Synthesis of Thiocarbamoylpyrazoles and Application as an Alternative Latent Fingermark Developers

Rosa¹,

Venzke²,

Poletti³

et al. 2020

J. Braz. Chem. Soc.

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Fingerprints are unique to each individual, contributing to human identification in forensic cases. The powder technique being widely used is considered one of the most important in latent fingermarks analysis. In this sense, the present work aimed to synthesize 1-thiocarbamoyl-4,5dihydro-1H-pyrazoles and apply them as powder agents to develop latent fingermarks. The compounds were prepared from an effective and green synthesis via the condensation of chalcones with thiosemicarbazide in ethanol under microwave irradiation. Pyrazoles were tested and compared with a standard white powder (Sirchie ®) on glass surfaces using sebaceous and natural fingermarks so that molecule 2c has been shown to be more promising providing image clarity. The derivatives of pyrazoles were promising as an alternative latent fingermark, presenting high quality images for fingermarks, proving to be a great tool for forensic sciences.

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Computational and experimental studies on dielectric relaxation and dipole moment of some anilines and phenol

Cited by 25 publications

References 19 publications

Electronic structural studies of pyrrolidinium‐based ionic liquids for electrochemical application

Electronic structural studies of pyrrolidinium‐based ionic liquids for electrochemical application

Studies on dielectric relaxation in relation to viscosity of some anilines, phenol, and their binary mixtures at microwave frequencies

Microwave Assisted Synthesis of Thiocarbamoylpyrazoles and Application as an Alternative Latent Fingermark Developers

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