Electron-donor Electron-acceptor Research Articles

Reversed-Phase Liquid Chromatography of Dansyl Amino Acids with Microspherical Octadecyl-Silica and Octadecyl-Zirconia Bonded Stationary Phases

Abstract A series of non-porous, microspherical octadecyl-silica and octadecyl-zirconia bonded stationary phases were introduced and evaluated in the HPLC of dansyl-amino acids over a wide range of elution conditions. The microspherical silica and zirconia particles were coated with either polymeric or monomeric octadecylsilyl layers. Polymeric octadecyl-silica columns afforded virtually no solute-support interaction, whereas polymeric octadecyl-zirconia bonded stationary phases exhibited metallic interaction with some dansyl amino acids, and their residual adsorptivities toward the separated analytes were comparable to those observed on monomeric octadecyl-silica columns without end-capping. These metallic interactions, which are of the electron donor-electron acceptor (EDA) type, predominate in the acidic pH region. However, the presence of small amounts of tartrate or phosphate ions in the eluent greatly reduced EDA interaction, and consequently allowed the high resolution separation of dansyl amino ac...

Electron donor-electron acceptor interactions in bimetallic surfaces: theory and XPS studies

Electron donor-electron acceptor interactions in bimetallic surfaces: theory and XPS studies

ChemInform Abstract: Electron Donor‐Electron Acceptor Complexes of Carbonyldiimidazoles and Thiocarbonyldiimidazoles with Iodine. Effect of Solvent Polarity

ChemInformVolume 21, Issue 23 Article ChemInform Abstract: Electron Donor-Electron Acceptor Complexes of Carbonyldiimidazoles and Thiocarbonyldiimidazoles with Iodine. Effect of Solvent Polarity A.-G. EL-KOURASHY, A.-G. EL-KOURASHY Dep. Chem., Fac. Sci., Cairo Univ., Giza, EgyptSearch for more papers by this authorR. H. ABU-EITTAH, R. H. ABU-EITTAH Dep. Chem., Fac. Sci., Cairo Univ., Giza, EgyptSearch for more papers by this author A.-G. EL-KOURASHY, A.-G. EL-KOURASHY Dep. Chem., Fac. Sci., Cairo Univ., Giza, EgyptSearch for more papers by this authorR. H. ABU-EITTAH, R. H. ABU-EITTAH Dep. Chem., Fac. Sci., Cairo Univ., Giza, EgyptSearch for more papers by this author First published: June 5, 1990 https://doi.org/10.1002/chin.199023085Read the full textAboutPDF 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 onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume21, Issue23June 5, 1990 RelatedInformation

Electron-donor–electron-acceptor association constants of pyrene with 2,4,6-trinitrotoluene in solution determined by 1H-nuclear magnetic resonance from non-linear Scatchard plots

The chemical shifts of the ring and methyl protons of 2, 4, 6-trinitrotoluene have been measured as a function of the concentration of added pyrene in solutions in carbon tetrachloride at 33.5 °C. Simple analysis at the 95 % confidence level yields association constants K= 8.42 ± 0.1 and 7.92 ± 0.1 kg mol–1 from these two probes, respectively. Allowance for ‘additional unspecific shielding’ increases these values to K= 9.10 ± 0.05 and 8.84 ± 0.06 kg mol–1. Alternatively, analysis based on a double equilibrium forming complexes with stoichiometry DA and D2A results in association constants K1= 8.7 ± 0.2 and 8.4 ± 0.3 kg mol–1, and K2= 0.23 ± 0.05 and 0.31 ± 0.07 kg mol–1 from HAr and HMe, respectively. Thus, whilst the model of a simple 1:1 association is untenable, the data do not provide a clear choice between the second and third models in this particular system.

Dark catalytic electron transfer in solid-state hydrogen-bonded electron-donor–electron-acceptor complexes

The mechanism for the catalysis of electron-transfer reactions in systems with weak donor–acceptor properties has been considered. According to this mechanism, the reaction proceeds via the low-lying excited states of the complexes. These states are generated as a result of multiorbital bonds between the molecules of the reagents. The significant part played by hydrogen and other bridge bonds in the stabilization of the excited levels of the complexes is shown. The energetic characteristics of complexation (charge-transfer energy) and hydrogen-atom transfer (activation energy and reaction heat) are compared, taking as an example solid-phase hydrogen-bonded π complexes.

Electron acceptor-electron donor interactions. XV. Examination of some weak charge-transfer interactions and the phenomenon of thermochromism in these systems

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTElectron acceptor-electron donor interactions. XV. Examination of some weak charge-transfer interactions and the phenomenon of thermochromism in these systemsP. R. Hammond and L. A. BurkardtCite this: J. Phys. Chem. 1970, 74, 3, 639–646Publication Date (Print):February 1, 1970Publication History Published online1 May 2002Published inissue 1 February 1970https://doi.org/10.1021/j100698a027RIGHTS & PERMISSIONSArticle Views160Altmetric-Citations11LEARN 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 (946 KB) Get e-Alerts

Electron acceptor-electron donor interactions. XVI. Charge-transfer spectra for solutions of tungsten and molybdenum hexafluorides and iodine heptafluoride in n-hexane and cyclohexane. Donor properties of the aliphatic hydrocarbons

Electron acceptor-electron donor interactions. XVI. Charge-transfer spectra for solutions of tungsten and molybdenum hexafluorides and iodine heptafluoride in n-hexane and cyclohexane. Donor properties of the aliphatic hydrocarbons

Investigation of the chemical adsorption of gases on nickelous oxide and of its solid solutions with lithium oxide

1. Kinetic relations have been investigated for the adsorption of electron-donor gases (CO and C2H2) and electron acceptor gases (O2 and CO2, on NiO and its solid solutions with Li2O and Fe2O3, and also on ternary solid solutions (NiO, Li2O, Fe2O3). 2. The presence of small amounts of dissolved metal oxides alters the electrical conductivity of NiO, and has a profound effect on its chemical adsorption. The adsorptions of electron-donor and of electron-acceptor gases are affected in opposite directions. 3. The presence of dissolved additives alters the form of the adsorption kinetics. 4. The changes in activation energy, for the adsorption of electron-donor and electron-acceptor gases, cannot be explained by the changes in level of chemical potential. 5. According to isotope-exchange data, the active surfaces of NiO and of its solid solutions of Li2O are heterogeneous. 6. The hypothesis is advanced that active centers for the adsorption of electron-acceptor gases (such as oxygen) are formed by electrons on acceptor additive centers. Active centers for electron-donor gases (CO and acetylene) are Ni3 cations, not bonded to additives. 7. An investigation of the adsorptive properties of solid solutions, with known structural and electronic properties, is the prospective method which should lead to a deeper understanding of the laws of chemical adsorption and of their physical and chemical nature.