An analysis of errors in estimating association constants and molar extinction coefficients from spectrophotometric data for 1 : 1 molecular complexes. Application to literature data

1982 ◽  
pp. 53 ◽  
Author(s):  
Gino Carta ◽  
Guido Crisponi
Keyword(s):  
Molecular Complexes ◽  
Association Constants ◽  
Extinction Coefficients ◽  
Spectrophotometric Data ◽  
Molar Extinction Coefficients

ASSOCIATION OF CERIC IONS WITH SULPHATE (A SPECTRAL STUDY)

1951 ◽  
Vol 29 (10) ◽  
pp. 828-837 ◽  
Author(s):  
T. J. Hardwick ◽  
E. Robertson
Keyword(s):  
Spectral Study ◽  
Association Constants ◽  
Extinction Coefficients ◽  
Ceric Ion ◽  
Molar Extinction Coefficients

Ceric ion has been shown to associate with sulphate ion to form successively Ce(SO4++, Ce(SO4)2, and Ce(SO4)3−. The association constants relating these species have been determined at 25 °C. The molar extinction coefficients of each associated complex have been found between 395 and 430 mμ. Migration experiments bear out the results qualitatively.

scholarly journals Spectrophotometric Determination of the Ionization Constants for the Oximes – Cholinesterases Reactivators at Different Temperatures

2019 ◽  
Vol 2 (3) ◽  
pp. e00097
Author(s):  
T.V. Schäfer ◽  
A.A. Tyaptin ◽  
T.B. Pechurina
Keyword(s):  
Aqueous Solutions ◽  
Incubation Medium ◽  
Ph Value ◽  
Ionization Constants ◽  
Medium Ph ◽  
Extinction Coefficients ◽  
Spectrophotometric Data ◽  
Different Temperatures ◽  
Molar Extinction Coefficients

The goal of study was the determination of the ionization constants for the oximes – cholinesterases reactivators in aqueous solutions at different temperatures. The wavelengths of absorption maxima of the protonated and deprotonated oxime groups, the molar extinction coefficients of the various oximes species, and the ionization constants for the oxime cholinesterases reactivators (isonitrosin, pralidoxime, dipyroxime, toxogonin, methoxime, carboxime and asoxime) were obtained using spectrophotometric data (wavelength 190 to 450 nm) in solutions (pH 5 – 12) at 20°C, 25°C and 37°C. The proportion of nucleophilic forms involved in the oxime-induced reactivation of phosphorylated cholinesterases was shown to be is positively dependent on the incubation medium pH value and temperature. A hypothesis that the temperature affects the oximes ability to reactivate phosphorylated cholinesterases has been proposed.

Charge-Transfer Complexes of Brominated Polycyclic Aromatic Hydrocarbons

1962 ◽  
Vol 15 (2) ◽  
pp. 278 ◽  
Author(s):  
TM Spotswood
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Charge Transfer ◽  
Aromatic Hydrocarbons ◽  
Charge Transfer Complex ◽  
Equilibrium Constants ◽  
Molecular Complexes ◽  
Charge Transfer Complexes ◽  
Extinction Coefficients ◽  
Polycyclic Aromatic ◽  
Molar Extinction Coefficients

Charge-transfer complex formation between the donors 1-bromonaphthalene. 9-bromophenanthrene, 9-bromoanthracene, 3-bromopyrene, and 7-bromobenz[a]-anthracene and the acceptors iodine, tetrachlorophthalic anhydride, 1,3,5-trinitrobenzene, and 2,4,7-trinitrofluorenone has been investigated. The positions of the charge-transfer absorption maxima, apparent molar extinction coefficients, and equilibrium constants have been determined in carbon tetrachloride solution and the results compared with those for the corresponding unsubstituted polycyclic aromatic hydrocarbons. The positions of the absorption maxima of the charge-transfer bands of the brominated hydrocarbons were anomalous but the apparent molar extinction coefficients and equilibrium constants were similar to those obtained for the parent hydrocarbons. The strength of charge-transfer bonding in molecular complexes of brominated polycyclic aromatic hydrocarbons is shown to be of the same order as that in molecular complexes of the unsubstituted hydrocarbons.

Synthesis and characterization of meso-to-meso directly linked porphyrin-diazaporphyrin triads

2018 ◽  
Vol 22 (09n10) ◽  
pp. 814-820
Author(s):  
Yingying Jia ◽  
Ling Xu ◽  
Bangshao Yin ◽  
Mingbo Zhou ◽  
Jianxin Song
Keyword(s):  
Nickel Complex ◽  
High Resolution Mass Spectrometry ◽  
Dihedral Angles ◽  
X Ray Diffraction ◽  
Extinction Coefficients ◽  
X Ray ◽  
H Nmr ◽  
First Time ◽  
Molar Extinction Coefficients

Beginning with 5,10,15-triarylporphyrin-nickel complex, five meso-to-meso directly linked porphyrin-diazaporphyrin triads were successfully prepared for the first time through a series of reactions including formylation via Vilsmeier–Haack reaction, condensation with pyrrole, bromination with [Formula: see text]-Bromosuccinimide (NBS), oxidation with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), metal-templated cyclization of dibromodipyrrin-metal complexes with NaN[Formula: see text] and demetalization. All these triads were comprehensively characterized by [Formula: see text]H NMR, high-resolution mass spectrometry and UV-vis absorption. In addition, the structure of compound 6Ni was unambiguously determined by X-ray diffraction analysis, which showed that the two dihedral angles are both 86.65 (4)[Formula: see text] between each mean plane of porphyrin and that of central diazaporphyrin The UV-vis absorption spectra disclosed that the longest wavelengths of Soret bands and Q bands for these triads were observed at 429 and 642 nm, respectively. In contrast to diazaporphyrin-porphyrin dyads, diazaporphyrin dimers and diazaporphyrin monomers reported previously the molar extinction coefficients, particularly for triad 8Ni are much higher.

scholarly journals Quantification of acidic sites of nanoscopic hydroxylated magnesium fluorides by FTIR and 15N MAS NMR spectroscopy

RSC Advances ◽  
2015 ◽  
Vol 5 (109) ◽  
pp. 89659-89668 ◽  
Author(s):  
Felix Hemmann ◽  
Iker Agirrezabal-Telleria ◽  
Christian Jaeger ◽  
Erhard Kemnitz
Keyword(s):  
Nmr Spectroscopy ◽  
Mas Nmr ◽  
New Method ◽  
Extinction Coefficients ◽  
Surface Sites ◽  
Acidic Sites ◽  
Molar Extinction Coefficients

A new method is described for the calculation of molar extinction coefficients for quantitative FTIR measurements of acidic surface sites.

EXPERIMENTAL STUDIES OF SOLUTION PROCESSES: VI. EFFECT OF SOLVENT ON INFRARED ABSORPTION SPECTRA

1960 ◽  
Vol 38 (10) ◽  
pp. 1921-1926 ◽  
Author(s):  
P. A. D. De Maine ◽  
L. H. Daly ◽  
M. M. De Maine
Keyword(s):  
Infrared Absorption ◽  
Experimental Studies ◽  
Absorption Data ◽  
Frequency Shifts ◽  
Extinction Coefficients ◽  
Effect Of Solvent ◽  
Solution Processes ◽  
Pure Substances ◽  
Infrared Absorption Spectra ◽  
Molar Extinction Coefficients

Here are reported infrared absorption data between 4000 cm−1 and 700 cm−1 near 19 °C for methanol, n-propanol, isopropanol, cyclohexanol, benzyl alcohol, diethyl ether, anisole, 1,4-dioxane, diisopropyl ether, nitromethane, acetone, p-xylene, benzene, and hexane as pure substances and in carbon tetrachloride solution. Band frequencies accurate to within 1 cm−1 are reported. Except for the 3340 cm−1 band in dilute MeOH solutions no frequency shifts were observed even with gross changes of the electrical properties of the solutions. Molar extinction coefficients at absorption maxima are discussed briefly.

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