L. C. B. O.: An Easy Method to Predict Valence Ionization Energies. Application to Substituted Benzenes

1981 ◽  
Vol 36 (12) ◽  
pp. 1344-1351 ◽  
Author(s):  
Alberto Modelli ◽  
Giuseppe Distefano
Keyword(s):  
Conformational Analysis ◽  
Ionization Energy ◽  
Internal Standard ◽  
Electron Affinities ◽  
Easy Method ◽  
Simple Method ◽  
Substituted Benzenes ◽  
Ionization Energies ◽  
Monosubstituted Benzenes ◽  
Coulomb Integrals

AbstractThe linear combination bond orbitals (L.C.B.0.) MO treatment has been used to reproduce the π ionization energies of several ortho-, meta-and para-disubstituted benzenes. The Coulomb integral of the substituent π orbitals and their resonance integrals with the ring π orbitals have been obtained from the spectra of the corresponding monosubstituted benzenes, using the same procedure for all the compounds under examination. The ring Coulomb integrals have been chosen taking, as an internal standard, the experimental ionization energy value of the π[a2) orbital, non interacting by symmetry in the monosubstituted and in the para-disubstituted compounds. An application of this simple method to conformational analysis and to electron affinities is also shown.

On an Ionic Approximation to Donor-Acceptor and Ion-Molecule Bonding, with Reference to Solvation Effects

1975 ◽  
Vol 30 (6-7) ◽  
pp. 845-854
Author(s):  
G.van Hooydonk
Keyword(s):  
Chemical Bonding ◽  
General Scheme ◽  
Ion Solvation ◽  
Electron Affinities ◽  
Neutral Species ◽  
Ionization Energies ◽  
Solvation Effects ◽  
Donor Acceptor ◽  
Molecule Interactions

Abstract An ionic, i. e. essentially electrostatic, approximation to donor-acceptor bonding between neutral species, ion-molecule interactions and corresponding solvation effects is forwarded. Drago's E-C equation for donor-acceptor reactions and the elimination of solvation procedure (ESP), presented by Drago et al., can consistently by incorporated in the general scheme. The theory yields further correct values for bulk ion-solvation enthalpies of cations H+,Li+,Na+,K+,Rb+ in water with the aid of ionization energies and electron affinities only. The formulae deduced for these types of chemical bonding represent the equivalent of the electronegativity-based theory for the description of ordinary chemical bonding between atoms, introduced earlier.

Theoretical prediction of proton and electron affinities, gas phase basicities, and ionization energies of sulfinamides

2019 ◽  
Vol 31 (1) ◽  
pp. 411-421
Author(s):  
Masoumeh Ghahremani ◽  
Hamed Bahrami ◽  
Hamed Douroudgari ◽  
Morteza Vahedpour
Keyword(s):  
Theoretical Prediction ◽  
Gas Phase ◽  
Electron Affinities ◽  
Ionization Energies ◽  
Gas Phase Basicities

Determination of the ionization energies and electron affinities of some dyes of photographic importance

1974 ◽  
Vol 19 (5) ◽  
pp. 215-225 ◽  
Author(s):  
Louis Gouverneur ◽  
Georges Leroy ◽  
Istvan Zador
Keyword(s):  
Electron Affinities ◽  
Ionization Energies

scholarly journals A simple method for the analysis of urinary sucralose for use in tests of intestinal permeability

2005 ◽  
Vol 42 (3) ◽  
pp. 224-226 ◽  
Author(s):  
A D G Anderson ◽  
P Poon ◽  
G M Greenway ◽  
J MacFie
Keyword(s):  
Refractive Index ◽  
Limit Of Detection ◽  
Internal Standard ◽  
Simple Method ◽  
Standard Curve ◽  
Additional Information ◽  
Accuracy And Precision ◽  
Analytical Recovery ◽  
Peak Areas ◽  
Syringe Filter

Background: Sucralose is a unique disaccharide probe which is stable in the colon and can be used to assess permeability over the whole gut. Additional information can be gained when sucralose is administered in combination with lactulose and a monosaccharide such as L-rhamnose in the form of a 'triple sugar test.' We describe a simple assay for urinary sucralose by HPLC with refractive index detection (HPLC-RI). Methods: Phenyl-β-D-glucopyranoside (internal standard) was added to 10 mL of urine, which was then passed through a 0.45 μm syringe filter. Elution was with 30% methanol (1 mL/min) on a reverse-phase C18 column. Detection was by refractive index, and integration based upon peak areas. Sixty standards of sucralose in human urine were analysed in order to quantify analytical variation. Results: The standard curve for urinary sucralose was linear from 25 to 500 mg/L ( r>0.99). The limit of detection was 11 mg/L. Analytical recovery of sucralose at concentrations of 25, 50 and 100 mg/L was 101.5% (CV 7.59%), 102.9% (CV 5.82%) and 105.0% (CV 4.26%), respectively Conclusions: The technique described represents a simple assay for urinary sucralose which performed with acceptable accuracy and precision and should facilitate the use of the triple sugar test in clinical research.

Direct, simultaneous measurement of chloramphenicol and its monosuccinate ester in micro-samples of plasma by radial-compression liquid chromatography.

1987 ◽  
Vol 33 (10) ◽  
pp. 1814-1816 ◽  
Author(s):  
A el-Yazigi ◽  
A Yusuf ◽  
A Al-Humaidan
Keyword(s):  
Sodium Succinate ◽  
Acetic Acid Solution ◽  
Internal Standard ◽  
Peak Height ◽  
Radial Compression ◽  
Solution Ph ◽  
Liquid Chromatograph ◽  
Simple Method ◽  
Micron Particle ◽  
Total Analysis

Abstract A simple method of simultaneous analysis for chloramphenicol and chloramphenicol succinate in 10-microL samples of plasma is described. We injected the plasma samples directly into a radial-compression liquid chromatograph equipped with a precolumn module and a C18 insert. A mixture of acetic acid solution (pH 3)/acetonitrile (75/25, by vol) was used as mobile phase, at a flow rate of 4 mL/min. We separated the compounds in a 10-micron (particle size) C18 cartridge with a radial compression separation system and detected them in the effluent at 280 nm. The peak height for both compounds was linearly (r greater than 0.9993) related to concentration over the range investigated, 1-50 mg/L. We also performed the analysis with use of an internal standard (methylprednisolone) and obtained equally good results (r greater than 0.9995). We observed no interference from other antibiotics or drugs in the assay, and the inter- and intra-run precision at different concentrations was good (CV, 0 to 5.6%). We analyzed microsamples of plasma from an infant treated for meningitis with chloramphenicol sodium succinate intravenously. Total analysis time for each sample was less than 8 min.

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