The Vibrational Spectra and Structure of Dimethyl Carbonate and its Conformational Behavior

Katon, J. E.; Cohen, Mark

doi:10.1139/v75-191

Cited by 88 publications

(63 citation statements)

References 5 publications

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“…The relative population we found is 99:1, in agreement with the ED and spectroscopic findings. 6,7 Experimental RDF peaks centered at distances larger than approximately 5 Å are progressively wider, as a consequence of the increasing contribution of intermolecular contacts, whose spatial variance is larger, due to the nonbonded interaction.…”

Section: Resultsmentioning

confidence: 99%

“…1͑b͔͒. In the liquid state, spectroscopic ͑infrared and Raman͒ results 7 highlighted the existence of a ͑thermally activated͒ equilibrium between two conformers ͓namely, cis-cis and cis-trans, Figs. 1͑b͒ and 1͑c͔͒ between 20 and 50°C, while no indication of the existence of the energetically unstable trans-trans conformer ͑with both methoxy groups pointing away from a͒ Electronic mail: gontrani@caspur.it and l.gontrani@caspur.it.…”

Section: Introductionmentioning

confidence: 88%

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An energy dispersive x-ray scattering and molecular dynamics study of liquid dimethyl carbonate

Gontrani

Russina

Marincola

et al. 2009

The Journal of Chemical Physics

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In this work, we report on the first x-ray diffraction study on liquid dimethyl carbonate. Diffraction spectra were collected with an energy-dispersive instrument, whose wide Q-range allows the structure determination of weakly ordered systems (such as liquids). The structural correlation in this liquid ranges up to about 20 A. The observed patterns are interpreted with a structural model derived from classical molecular dynamics simulations. The simulations were run using OPLS force field, only slightly modified to restrain bond distances to the experimental values. The model structure function and radial distribution functions, averaged among the productive trajectory frames, are in very good agreement with the corresponding experimental ones. Molecular dynamics results show that the deviations from C(2v) cis-cis structure, predicted by ab initio calculations and observed by electron diffraction in the gas phase, are small. By analyzing the intra- and intermolecular pair distribution functions, it was possible to assign the peaks of the experimental radial distribution function to specific structural correlations, and to compute the different average intermolecular coordination numbers. The intermolecular methyl-carbonyl oxygen distance is thoroughly discussed to assess the presence of weak C-H...O hydrogen bonds.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 88%

An energy dispersive x-ray scattering and molecular dynamics study of liquid dimethyl carbonate

Gontrani

Russina

Marincola

et al. 2009

The Journal of Chemical Physics

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“…arrived at here, and which are based on a combination of ab initio and experimental data, di †er markedly from those given previously. 5,7 In contrast with the accidental degeneracies of CH 3 stretches and deformations, all four rocking modes are predicted to occur well separated. The order in which they are predicted, with band contours and IR intensities indicated in brackets, is 2.3), 15.0), 1.4) and l 6 (B, l 21 (A, l 27 (C, In this region of the vapor phase IR spectra, l 13…”

Section: Vibrational Spectra and Assignmentsmentioning

confidence: 96%

“…Also, if we set the lower limit of a conformational splitting that can be detected in the experimental spectra at 5 cm~1, then the ab initio frequencies in Table 2 suggest that doublets should occur for 15 fundamental modes : this is signiÐcantly more than the number of conformational bands listed by Katon et al6,7 For these reasons we have critically evaluated our spectra, paying speciÐcally attention to the occurrence of conformational splittings.…”

Section: Conformational Analysismentioning

confidence: 99%

On the conformational behavior of dimethyl carbonate

Bohets¹,

Veken²

1999

Phys. Chem. Chem. Phys.

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Infrared (4000È50 cm~1) spectra of the vapor, the amorphous and crystalline solid phase, and Raman spectra (4000È50 cm~1) of the vapor, liquid and crystalline solid phases of dimethyl carbonate have been recorded, and assignments are proposed. MP2 and DFT ab initio calculations were carried out using a 6-31G** basis set. The calculations show that the compound can occur as the cisÈcis, cisÈtrans and near-transÈnear-trans conformers, with the cisÈcis being the global minimum. Vibrational frequencies and solvation free enthalpies were predicted on the DFT level of theory. Both cisÈcis and cisÈtrans conformers were identiÐed in the vibrational spectra of all Ñuid phases. The enthalpy di †erence between them was determined to be 8.0(4) kJ mol~1 in the pure liquid phase and 13.6(9) kJ mol~1 in the vapor phase.

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“…The negative-going bands present in all of the spectra correspond to most of the vibrational modes of species belonging to the electrolyte, indicating the formation of a homogeneous, well-covering thin fi lm at the electrode surface during electrochemical cycling. [ 37,38,[48][49][50] A large number of studies were dedicated to characterize electrolyte properties and the resulting SEI layer. The right-hand frame in Figure 2 shows the high-wavenumber region with a different absorbance scale (enlarged by a factor of six).…”

Section: Sei Formation In Lipf 6 -Based Electrolyte Containing Vc Andmentioning

confidence: 99%

Spectroscopic Insight into Li‐Ion Batteries during Operation: An Alternative Infrared Approach

Corte

Caillon

Jordy

et al. 2015

Advanced Energy Materials

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special environment for its characterization appear as steps which in most cases might strongly modify the active material. [ 1 ] Benefi ting from characterization techniques able to analyze the electrodes in situ and in operando therefore appears of uttermost importance for obtaining information of direct relevance regarding the electrode processes. We show in the present work that such pieces of information can be obtained by using in situ Fourier-transform infrared (FTIR) spectroscopy in a suitable geometry, which avoids the traditional limitations associated with this technique and allows for quantitative information to be extracted. [ 2 ] This approach therefore brings significant complementary information to other useful techniques operating in the electrochemical environment, which focus either on electrode materials, such as nuclear magnetic resonance (NMR) [ 3,4 ] or X-ray absorption, diffraction or imaging, [ 5,6 ] or on electrode surfaces, such as scanning probe microscopies. [ 7,8 ] Using infrared spectroscopy at the electrochemical interface has already been attempted in the context of the study of battery electrodes. [9][10][11] The geometry adopted for these studies was however severely limiting the sensitivity, and imposing stringent limitations for the electrochemical conditions (especially in terms of mass-transport limitations), which have direct impact on the obtained results. [ 12 ] Here, we use an alternative approach based on the multiple-internal-refl ection geometry, which allows for benefi ting from an enhanced sensitivity and working in electrochemical conditions similar to those of standard batteries for studying thin-fi lm electrodes. As shown hereafter, such a capability provides useful information of direct relevance for both interfacial and bulk electrode processes.The present study has been devoted to silicon electrodes, studied in a half-cell confi guration against a lithium-metal electrode. Silicon represents an impressive gain in energy density for negative electrodes in Li-ion batteries. One strategy to overcome the poor capacity retention associated with the massive volume expansion of silicon during lithiation is the use of nanosized geometries, for instance, particles, [13][14][15][16] wires, [17][18][19] and tubes. [ 20,21 ] The use of a thin-fi lm geometry also prevents Multiple-internal-refl ection infrared spectroscopy allows for the study of thin-fi lm amorphous silicon electrodes in situ and in operando, in conditions typical of those used in Li-ion batteries. It brings an enhanced sensitivity, and the attenuated-total-refl ection geometry allows for the extraction of quantitative information. When electrodes are cycled in representative electrolytes, the simultaneously recorded infrared spectra give an insight into the solid/electrolyte interphase (SEI) composition. They also unravel the dynamic behavior of this SEI layer by quantitatively assessing its thickness, which increases during silicon lithiation and partially decreases during delithiation. Li-ion solvation ...

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The Vibrational Spectra and Structure of Dimethyl Carbonate and its Conformational Behavior

Cited by 88 publications

References 5 publications

An energy dispersive x-ray scattering and molecular dynamics study of liquid dimethyl carbonate

An energy dispersive x-ray scattering and molecular dynamics study of liquid dimethyl carbonate

On the conformational behavior of dimethyl carbonate

Spectroscopic Insight into Li‐Ion Batteries during Operation: An Alternative Infrared Approach

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