Normal coordinate analysis of some esters; methyl formate, methyl acetate and dimethyl oxalate

Matzke, P.; Chacón, Óscar; Andrade, Carlos

doi:10.1016/0022-2860(71)85042-1

Cited by 34 publications

(8 citation statements)

References 7 publications

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“…Although the main focus here is on BChl, DFT computation of normal modes was also performed on MeA and pyrrole. For the two molecules we find vibrational frequencies in good agreement with experimental values40, 41 with average deviations of about 2.3%. In MeA, poorer agreement was found only for two particular frequencies identified as rocking in CH 3 groups at 1000 cm −1 , where the deviations is 8.5%.…”

Section: Parametrization Of Bacteriochlorophyllssupporting

confidence: 88%

“…In general, the optimized coordinates obtained from ab initio DFT techniques such as those used in this article are always in good agreement with X‐ray determined structures. Specifically, for the small MeA molecule we found deviations less than 0.01 Å for bond lengths and less than 1° for bond angles found in literature 40, 41. For BPh structural results can be compared with the X‐ray structure of MeBph 12.…”

Section: Parametrization Of Bacteriochlorophyllssupporting

confidence: 50%

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An ab initio force field for the cofactors of bacterial photosynthesis

Ceccarelli¹,

Procacci²,

Marchi³

2002

J Comput Chem

110

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This article presents a new ab initio force field for the cofactors of bacterial photosynthesis, namely quinones and bacteriochlorophylls. The parameters has been designed to be suitable for molecular dynamics simulations of photosynthetic proteins by being compatible with the AMBER force field. To our knowledge, this is the first force field for photosynthetic cofactors based on a reliable set of ab initio density functional reference data for methyl bacteriochlorophyll a, methyl bacteriopheophytin a, and of a derivative of ubiquinone. Indeed, the new molecular mechanics force field is able to reproduce very well not only the experimental and ab initio structural properties and the vibrational spectra of the molecules, but also the eigenvectors of the molecular normal modes. For this reason it might also be helpful to understand vibrational spectroscopy results obtained on reaction center proteins.

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Section: Parametrization Of Bacteriochlorophyllssupporting

confidence: 88%

Section: Parametrization Of Bacteriochlorophyllssupporting

confidence: 50%

An ab initio force field for the cofactors of bacterial photosynthesis

Ceccarelli¹,

Procacci²,

Marchi³

2002

J Comput Chem

110

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“…The normal coordinate analysis of Matzke et al (19) suggests that this is a mixed mode with 39.5% H3C-C stretch, 24.3% C-0 stretch, 16.7% 0-C-0 bend, and 11.5% C=O stretch. In a later report by George et al (14) the v,, mode is assigned to the CH3-0 stretch.…”

Section: Introductionmentioning

confidence: 99%

A Raman spectral study of solvation and ion association in the systems LiAsF₆/CH₃CO₂CH₃ and LiAsF₆/HCO₂CH₃

Deng¹,

Irish²

1991

Can. J. Chem.

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ZHONGYI DENG and DONALD E. IRISH. Can. J. Chem. 69, 1766 (1991).The structure of the solvated lithium cation in methyl acetate (MA) solutions has been investigated using Raman spectroscopy. Two bands at 844 and 864 cm-' have been assigned to two different types of MA: the former is from the bulk solvent and the latter arises from MA molecules solvating the lithium cation. From measurement of changes in intensity of these bands with increasing salt concentration a solvation number of four for Li+ in MA has been inferred. Changes in the Raman bands at ca. 1740 cm-' suggest that solvation occurs through the carbonyl group. Evidence for contact ion pairing between Li'and AsF; is also presented. An equilibrium between solvent-shared ion pairs and contact ion pairs is proposed for which an equilibrium constant is estimated. The system LiAsF,Imethyl formate (MF) is similar in structure.Key words: Raman, ion pair formation, lithium and hexafluoroarsenate ions, methyl acetate and formate, lithium ion solvation. IntroductionThe search for new electrolyte-solvent systems capable of providing improved performance of both primary and secondary lithium cells and batteries is ongoing. Aprotic solvents, such as ethers, esters, amides carbonates, nitriles, and dimethyl sulfoxide, either alone or mixed, have received extensive study (1). Effort has been focused on overcoming the inferior conductivity of the electrolyte, relative to aqueous systems. Recently methyl formate (MF) and methyl acetate (MA) were identified as possible solvents (2-5). Conductance measurements (3-5) and, for MAILiAsF, and MALiClO,, microwave relaxation spectroscopy and some infrared spectra (5) have been reported. Solutions of MA have a surprisingly high conductance over a wide temperature range. Despite evidence for ion pairing, strong ion-solvent interactions were also suggested in these studies.Raman spectroscopy has proved to be a powerful technique for probing ion-ion and ion-solvent interactions. Recently Hyodo and Okabayashi studied local structure in LiClO,/EC (ethylene carbonate) and mixed solvent systems (6). We have reported Li' solvation in CH,CN solutions, and adsorption of the species at silver electrode surfaces (7). In anticipation of surface

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“…The conformational problem of esters has been the subject of great interest for many years [ 5 1 . For methylacetate a heavy-atom planar "cis" ( 2 ) conformation has been confirmed by investigations of dipole moments [6-9 1, electron diffraction patterns [lo 1, infrared [11][12][13] 1 and microwave spectra [14 1. The presence of an equilibrium between Z and E rotamers has only been suggested from ultrasonic studies [151.…”

Section: Introductionmentioning

confidence: 92%

Matrix Isolation Infrared Spectra of Methylacetate III. UV-Induced Z→E photorotamerisation of Methylacetate in Argon Matrices

Lenaerts

Daeyart

Vanderveken

et al. 1989

Spectroscopy Letters

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Broadband UV-irradiation of methylacetate isolated in argon matrices causes rather strong modifications to appear in the IR spectrum. Evidence was obtained for a photochemical interconversion of the stable 2-conformer into the less stable E-conformer followed by photolytic decomposition of the latter into stable products. Most of these products could be identified from their IR absorptions. The reverse E d 2 interconversion is a thermal process with an activation energy of about 10 kJmole-l. A normal coordinate analysis based on a * Research Associate of the Belgian NFWO 289 Copyright 0 1989 by Marcel Dekker, Inc. Downloaded by [UQ Library] at 08:06 23 June 2015 290 LENAERTS ET AL.transferable valence force field obtained from the literature allowed to assign approximate IR frequencies of E-methylacetate.

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Normal coordinate analysis of some esters; methyl formate, methyl acetate and dimethyl oxalate

Cited by 34 publications

References 7 publications

An ab initio force field for the cofactors of bacterial photosynthesis

An ab initio force field for the cofactors of bacterial photosynthesis

A Raman spectral study of solvation and ion association in the systems LiAsF₆/CH₃CO₂CH₃ and LiAsF₆/HCO₂CH₃

Matrix Isolation Infrared Spectra of Methylacetate III. UV-Induced Z→E photorotamerisation of Methylacetate in Argon Matrices

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Normal coordinate analysis of some esters; methyl formate, methyl acetate and dimethyl oxalate

Cited by 34 publications

References 7 publications

An ab initio force field for the cofactors of bacterial photosynthesis

An ab initio force field for the cofactors of bacterial photosynthesis

A Raman spectral study of solvation and ion association in the systems LiAsF6/CH3CO2CH3 and LiAsF6/HCO2CH3

Matrix Isolation Infrared Spectra of Methylacetate III. UV-Induced Z→E photorotamerisation of Methylacetate in Argon Matrices

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A Raman spectral study of solvation and ion association in the systems LiAsF₆/CH₃CO₂CH₃ and LiAsF₆/HCO₂CH₃