Electrons In Ethanol Research Articles

Investigation of the Effects of Solvents on the Structural, Electronic and Thermodynamic Properties of Rosiglitazone Based on Density Functional Theory

Rosiglitazone ( C18H19N3O3S ) is an anti-diabetic drug that reduces insulin resistance in patients with type 2 diabetes. The parameters (bond lengths and bond angles), HOMO, LUMO, HOMO-LUMO energy gap, dipole moment, thermodynamic properties, total energy and vibrational frequencies and intensities of the Rosiglitazone molecule in gas phase and in solvents (Water, Ethanol, DMSO and Acetonitrile) were calculated based on Density Functional Theory (DFT) using standard basis sets: B3LYP/6-31G(d,p), B3LYP/6-31+G(d,p) and B3LYP/6-31++G(d,p). Windows version of Gaussian 09 was used for all the calculations. From the results obtained, the solvents have little influence on the optimized parameters of the molecule. The highest HOMO value of -5.433 eV was found in gas phase showing that the molecule will best donate electron in the gas phase, followed by ethanol in comparison with other solvents. The values of the HOMO were observed to increase with the decrease in dielectric constants of the solvents across all the basis sets used. The lowest LUMO energy of -1.448 eV was found to be in ethanol which shows that the molecule will best accept electron in ethanol compared to the gas phase and other solvents. The largest HOMO-LUMO gap of 4.285 eV was found in water which shows its higher kinetic stability and less chemical reactivity compared to other solvents and in the gas phase. The chemical softness of the molecule was found to decrease as the dielectric constants of the solvents increased namely from ethanol to water. The chemical hardness was found to slightly increase with the increase in dielectric constants of the solvents. The highest value of the dipole moment of 4.6874 D was found in water indicating that the molecule will have the strongest intermolecular interactions in water compared to other solvents and in the gas phase. The total energy increased as the dielectric constants of the solvents decreased from water to ethanol. The vibrational frequencies and intensities increased as the dielectric constants of the solvents increased from ethanol to water. The results confirmed the effects of solvents on the structural, electronic and thermodynamic properties of the studied molecule and will be useful in the design and development of rosiglitazone as an anti-diabetic drug.

Temperature and pressure dependence of the absorption spectra and decay kinetics of solvated electrons in ethanol from 22 to 250 °C studied by pulse radiolysis

The absorption spectra and the decay kinetics of solvated electron in ethanol have been investigated at different temperatures from 22 to 250 °C and pressures from 8 to 40 MPa, by using nanosecond pulse radiolysis techniques. The results show that the peak position of the absorption spectrum for solvated electron shifts to longer wavelength from 680 nm at 22 °C to about 1240 nm at 250 °C under 8 MPa. The lifetime of solvated electron becomes shorter with increasing temperature. The pressure dependence of the lifetime at elevated temperatures is more pronounced.

Solvation structure of excess electrons in ethanol and ethanol/2-methyl tetrahydrofuran mixtures

The solvation structures of excess electrons in {gamma}-irradiated ethanol and ethanol/2-methyltetrahydrofuran mixtures at 77 K have been determined by analyzing their optical absorption spectra. In the mixed matrices, the electrons show 5 spectral components with the absorption maxima at the wavenumbers 8.3, 10.2, 13.5, 16.6, and 19.0 {times} 10{sup 3} cm{sup {minus}1}, respectively. The relative intensities of these components depend on the concentration of ethanol. The first component is the same as the absorption spectrum of excess electrons in neat 2-methyltetrahydrofuran. The second, the third, the fourth, and the fifth components are due to the excess electrons solvated by one, two, three, and four ethanol molecules, respectively, with the molecular dipoles pointing toward the electron. In neat ethanol, two-third of the excess electrons are solvated by 4 ethanol molecules, with the molecular dipoles pointing toward the electron. The remaining electrons are also surrounded by four ethanol molecules. However, the molecular dipole of one of the four ethanol molecules does not point toward the electron. The possible structure of the electron localized in water is also discussed.

Study of solvated electrons in ethanol−Water mixtures at 77 K

Solvated electrons in ethanol-water mixtures at 77 K were investigated by optical absorption and ESR measurements over a wide range of concentrations. Abrupt changes of yield and spectral parameters were observed betwenn 12 and 14 mol% ethanol where a structural transition of the mixture had been reported.

ChemInform Abstract: GEOMETRICAL STRUCTURE OF SOLVATED ELECTRONS IN ETHANOL GLASS DETERMINED FROM ELECTRON SPIN ECHO MODULATION ANALYSES

Chemischer InformationsdienstVolume 12, Issue 28 Preparative Organic Chemistry ChemInform Abstract: GEOMETRICAL STRUCTURE OF SOLVATED ELECTRONS IN ETHANOL GLASS DETERMINED FROM ELECTRON SPIN ECHO MODULATION ANALYSES M. NARAYANA, M. NARAYANASearch for more papers by this authorL. KEVAN, L. KEVANSearch for more papers by this author M. NARAYANA, M. NARAYANASearch for more papers by this authorL. KEVAN, L. KEVANSearch for more papers by this author First published: July 14, 1981 https://doi.org/10.1002/chin.198128134AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume12, Issue28July 14, 1981 RelatedInformation

Electron spin echo modulation study of the geometry of solvated electrons in ethanol glass: An example of a molecular dipole oriented solvation shell

The analysis of the electron spin echo modulation patterns of solvated electrons in variously deuterated ethanol glasses shows that four ethanol molecules constitute the first solvation shell of the solvated electron with average distances of 2.2 Å to the OH protons, 3.3 Å to the CH2 protons, and 3.8 Å to the CH3 protons. These distances show that the OH bond of ethanol cannot be oriented towards the solvated electron. Instead the electron must be located along a line which approximately bisects the COH bond angle. This is the same direction as the molecular dipole orientation in ethanol and demonstrates that the solvated electron in ethanol has a molecular dipole oriented solvation shell in contrast to the OH bond oriented solvaton shell for the solvated electron in aqueous systems.

Comparison of photoconductivity and optical spectra for trapped electrons in aqueous and alcoholic glasses at 4.2 K

The photoconductivity and optical spectra of localized electrons generated at 4 K by radiolysis have been measured and compared with previous results at 85 K for a variety of polar aqueous and alcoholic matrices. At 85 K the localized electrons are largely solvated, characterized by an equilibrium distribution of solvent molecules around them. At 4 K the localized electrons have often not attained an equilibrium first solvation shell and are described as presolvated. The current results are discussed in terms of the binding energy and nature of the optical transitions associated with presolvated electrons vs solvated electrons in ethanol, ethylene glycol–water, 10 M NaOD/D2O, 7 M NaClO4/D2O and 5 M K2CO3/D2O glassy matrices.

An Upper Limit to the Excited Electron-Cation Recombination Lifetimes of Trapped Electrons in Ethanol and 2-Methyl-tetrahydrofuran Glasses at 4 and 77 K

Abstract N,N,N′,N′-Tetramethyl-p-phenylenediamine (TMPD) fluorescence lifetimes in 2-methyltetrahydrofuran (MTHF) glass at 77 K (13.5 ns) and in ethanol glass at 77 K (12.3 ns) and 4 K (11.5 ns) were measured using 347 nm excitation from a frequency doubled ruby laser. Trapped electrons and TMPD+ were generated in these matrices by photoionization and the recombination fluorescence stimulated by 694 nm laser light was found, within an experimental limit of 1 ns, to occur with the same lifetime as the directly excited fluorescence. A convolution analysis indicates that the electron-cation recombination lifetimes are ≤1 ns in all these matrices at the temperatures given. It is also suggested that a lower limit for the electron mobility of 0.005 cm2 V−1 s−1 is implied by these data.

Activated and activationless localization and impurity trapping of the electron in ethanol and ethanol-d

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTActivated and activationless localization and impurity trapping of the electron in ethanol and ethanol-dDusan Razem and William H. HamillCite this: J. Phys. Chem. 1978, 82, 4, 488–491Publication Date (Print):February 1, 1978Publication History Published online1 May 2002Published inissue 1 February 1978https://doi.org/10.1021/j100493a024RIGHTS & PERMISSIONSArticle Views21Altmetric-Citations7LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (498 KB) Get e-Alerts

Excess electrons in condensed media: Theory of optical absorption spectrum in molecular solutions

A theoretical formalism is developed for analyzing the spectra of excess electrons in pure molecular solids and liquids. A perturbation decomposition of the Hamiltonian allows the expression for the band shape I (ω) to be written as a sum of a zeroth order part, proportional to dipole transition matrix elements and corresponding Franck–Condon factors, and perturbation terms containing effects of electron hopping and their fluctuations. By using several physically motivated approximations (e.g., the temporally localized nature of electronic transitions which allows a short-time expansion of the time dependence of operators), the expression for I (ω) can be expressed in terms of solvent structure information and the electron–solvent interaction potential. From the general expressions for I (ω) a simplified model was developed in the special case of systems for which bound-to-bound transitions are dominant. This model has been successfully applied to the spectra of excess electrons in ethanol and anthracene glass, thereby providing some optimism for the potential use of the general formalism derived here.

Structure in the optical absorption spectrum of the solvated electron?

The optical absorption spectrum of the solvated electron in ethanol has been determined again to establish whether a report of observed structural features by Vannikov and Marevtsev, which appears to be discordant with earlier data, can be sustained. Our data do not reveal such structural features, and are, furthermore, in significant disagreement with the general contour of the absorption band reported by these authors.

Pulse radiolysis studies of time dependent spectral shifts of the solvated electron in ethanol and deuterated ethanol glasses at 76 K

The initial (?200 nsec) spectra of the trapped electron are similar in C2H5OH, C2H5OD, C2D5OH, and C2D5OD glasses at 76 K with λmax ∼1300 nm. The kinetics of the spectral shifts to the stable values of λmax near 540 nm are similar for C2H5OH and C2H5OD and resemble the kinetics of a series of first order processes or of tunneling reactions. Structure seems to be present in the partially relaxed spectra and may result from specific geoemetrical orientations of first solvation shell molecules.

Effect of Pressure on the Rates of Reaction of Solvated Electrons in Liquid Ethanol

At a γ radiolysis dose of 1× 1018 eV/g in ethanol at 296°K the hydrogen yields in neutral ethanol were G(H2)=5.0 at 1 bar and 5.5 at 5.3 kbar; in 1 mM and 1 M sulfuric acid G(H2)=5.7, independent of pressure. The electron scavengers nitrobenzene, acetone, and naphthalene reduce the hydrogen yields in neutral and acidic ethanol at 1 bar and 5.3 kbar; increasing the pressure greatly reduces the ease of scavenging the free ions but has only a small effect on scavenging efficiency in the spurs. Using as a standard the reaction esolv−→ C2H5Osolv−+H with k=1.2× 105 sec−1 at 1 bar and Δ V‡ =−14.4 cm2/mole averaged between 0 and 5.3 kbar, one obtains the following values for k(M−1· sec−1) and Δ V‡ (cm3/mole): esolv−+Hsolv+, 2.8× 1010 at zero ionic strength, +4.5; esolv−+C6H5NO2, 1.5× 1010, +7.5; esolv−+naphthalene, 5.0× 109, +5.6; esolv−+CH3COCH3, 4.2× 109, +5.1. The diffusion coefficient of solvated electrons in ethanol appears to correlate with the liquid viscosity; this is different from the behavior of electrons in alkanes. In ethanol Δ V‡diffusion≈ +7 cm3/mole for esolv− and +4 cm3/mole for Hsolv+. The free ion yield in ethanol is G(esolv−)fi=1.7, independent of pressure from 1 bar to 5.3 kbar; the model of Freeman and Fayadh [J. Chem. Phys. 43, 86 (1965)] is consistent with this behavior and it predicts that Gfi in methanol and water are also independent of pressure.

Application of the Semicontinuum Model to the Effect of Dipole Reorientation on Trapped Electron Spectra in Glassy Ethanol

A semicontinuum model is applied to trapped electrons in glassy ethanol at 77°K. The configurational stability of the ground state has been established. Ground, excited, and continuum states are calculated self-consistently for specific orientations from 80° to 0° of the molecular dipoles with respect to the trapped electron. It is shown that the spectral shifts observed for trapped electrons in pulse radiolysis experiments on alcohol glasses and the shifts observed upon warming from 4 to 77°K after γ irradiation at 4°K can be semiquantitatively accounted for by the molecular dipole orientation mechanism. The cavity radius of the trapped electron also increases somewhat upon dipole orientation but this is a small effect. The effect of dipole orientation upon other physical properties of the trapped electrons in ethanol is also discussed.

Detection of trapped electrons in organic glasses after gamma irradiation at 4.2 °K by electron spin resonance spectroscopy

Several organic glasses which are known to form trapped electrons when gamma irradiated at 77 °K have been irradiated at 4.2 °K and examined by electron spin resonance (e.s.r.) at the same temperature. In each case an absorption is observed which is probably due to trapped electrons. In three cases, the yield of trapped electrons at 4.2 °K seems to be as great as at 77 °K. In one case, a glassy alkane, the yield is enhanced at 4.2 °K. Trapped electrons in ethanol give a narrower e.s.r. line at 4.2 °K than at 77 °K, suggesting less orientation in the solvent cage.Trapped hydrogen atoms are not detected after irradiation at 4.2 °K. Contrary to prediction, hydrogen atoms are also not detected after post-irradiation photolysis of the trapped electrons.The results suggest that electron traps exist prior to irradiation and that molecular orientation via electronic dipole interaction is not a necessary condition for electron trapping. The results do not distinguish between trapping in solvent defects or trapping via electron-induced polarization of molecular orbitals.

Pulse Radiolysis Studies. VI. The Lifetimes of Aromatic Anions in the Aliphatic Alcohols

The formation and the lifetimes of several aromatic anions in irradiated solutions of arenes in the aliphatic alcohols have been investigated by the pulse radiolysis technique. The aromatic anions show a fast decay which follows a first-order rate law. The absolute rate constants for this decay, suggested to be a proton transfer from the alcohol, arene−+ROH=arene H·+RO−,have been determined for four alcohols and three aromatic anions. The rate constants, which are found to be in the order CH3OH>C2H5OH≅C3H7OH>(CH3)2CHOH, show a close correlation with other measurements of the acidity of the alcohols. The absolute rate constants have also been determined for the reaction of several aromatic anions with hydrogen ion, arene−+ROH2+=arene H·+ROH,and for the attachment reaction of the solvated electron in ethanol, esol−+arene=arene−.

Pulse Radiolysis Studies. IV. The Solvated Electron in the Aliphatic Alcohols

Some of the physical and chemical properties of the solvated electron in the aliphatic alcohols have been investigated by means of the pulse radiolysis technique. In ethanol the optical absorption spectrum exhibits a maximum at 700 mμ. The decadic molar extinction coefficient at 5461 Å is determined to be εe—sol5461=(1.1±0.4)×104 M—1 cm—1. From this the oscillator strength of the band from 270 mμ to about 980 mμ is estimated to be f=0.7. The radiation chemical yield of the solvated electron in ethanol is found to be 1.0±0.3 per 100 eV of absorbed energy. Absolute rate constants for a number of reactions of the solvated electron in ethanol and methanol have been determined. The diphenylide ion, formed by electron attachment to diphenyl in ethanol, shows a fast first-order decay for which the rate constant has been determined.

Photochemical Production of the Solvated Electron in Ethanol

Flash photolysis of several inorganic anions in ethanol gives an absorption spectrum attributed to the solvated electron.

Pulse radiolysis studies of the reactivity of the solvated electron in ethanol and methanol

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