Study of the complex of N-methyl-2-pyrrolidone with iodine (original) (raw)
Related papers
Journal of Solution Chemistry, 2012
The interaction of oxatomide (OXA), azacyclonol (AZA) and chloropheniramine (ClPA) antihistamine drugs with iodine was studied spectrophotometrically in different solvents and at three different temperatures. The electronic, FT-IR, far-IR, and mass spectra of the resulting charge-transfer (CT) complexes were recorded, in addition to thermal analysis. The results obtained show that the stoichiometries of the reactions are all 1:1. The observed time dependence of the CT band and subsequent formation of I À 3 in solution were related to the slow transformation of the initially formed 1:1 (donor: I 2) outer complex to an inner complex (electron donor-acceptor), followed by a fast reaction of the inner complex with iodine to form a triiodide ion. The characteristic strong absorptions of I À 3 are observed around 360 nm. The CT-complexes have the formulae [(OXA)I] ? I À 3 , [(AZA)I] ? I À 3 and [(ClPA)I] ? I À 3. The formation constants (K), molar absorption coefficients (e CT), and thermodynamic parameters DH # , DS # and DG # of these interaction have been determined and discussed.
Investigation of the electronic absorption spectra of some pyridine derivatives iodine complexes
Proceedings of the Indian Academy of Sciences - Section A, 1976
The electronic absorption spectra of some pyridine derivativesiodine complexes are measured and discussed. The thermodynamic constants of these complexes are calculated. It is confirmed that the stability of the complex depends on the type as well as the position of the substituent on pyridine nucleus. A linear relationship is obtained between the enthalpies-AH and the shift of the blue iodine band A "v of the complexes. It is also found that as the Pi electron density on the nitrogen atom increases, the stability of the complex also increases.
Journal of pharmaceutical and biomedical analysis, 2002
Thermodynamic studies on the charge-transfer complexes of sulfadoxine and pyrimethamine with chloranilic acid in non-aqueous 1,4-dioxan were investigated by spectrophotometric method. The absorption maxima for sulfadoxine and pyrimethamine were observed at 500 and 520 nm, respectively. We observed a bathochromic shift in the transitions of these complexes with respect to chloranilic acid, which absorb at 420 nm. The enthalpy of complexation was found to be −3.044 kJ/mole for pyrimethamine and − 5.934 kJ/mole for sulfadoxine. Equilibrium constant values were generally high, that is 261.202 l/mole and 344.29 l/mole for pyrimethamine and sulfadoxine, respectively, at 303 K. Free energy values were negative, of the order of − 14.420 kJ/mole for pyrimethamine and − 15.384 kJ/mole for sulfadoxine, indicating that complex formations were exothermic. These data suggest that the complexes are very stable. Arguments are presented to support the application of charge-transfer interactions in the quantitative analysis of these drugs.
Journal of Molecular Structure, 2017
UV-Vis spectroscopy has established that Pyridine substitutes form n→σ* charge transfer (CT) complexes with molecular Iodine. This study is a combined approach of purely experimental UV-Vis spectroscopy, Multiple linear regression theory and Computational chemistry to analyze the effect of solvent upon the charge transfer band of 2-Methylpyridine-I 2 and 2-Chloropyridine-I 2 complexes. Regression analysis verifies the dependence of the CT band upon different solvent parameters. Dielectric constant and refractive index are considered among the bulk solvent parameters and Hansen, Kamlet and Catalan parameters are taken into consideration at the molecular level. Density Functional Theory results explain well the blue shift of the CT bands in polar medium as an outcome of stronger donor acceptor interaction. A logarithmic relation between the bond length of the bridging atoms of the donor and the acceptor with the dielectric constant of the medium is established. Tauc plot and TDDFT study indicates a non-vertical electronic transition in the complexes. Buckingham and Lippert Mataga equations are applied to check the Polarizability effect on the CT band.
A comparative evaluation of two spectrophotometric methods for the assay of imipramine is described. The first method, based on UV spectrophotometry was compared with a second method which is based on the molecular interaction between imipramine and chloranilic acid, to form charge-transfer complexes in which the drug acts as n-donor and chloranilic acid as a π acceptor. A complete, detailed investigation of the complex formed was made with respect to its thermodynamic parameters. Good quantitative recoveries were achieved at 255 nm via UV spectrophotometry with Beer’s law being obeyed over the concentration range of 0.98-7.85 mg % for imipramine. Meanwhile, chloranilic acid was found to form a charge-transfer complex in a 1:1 stoichiometry with maximum absorption band at 526 nm. Conformity with Beer’s law was also evident over the concentration range of 1.96-19.63 mg %. Results from the evaluated thermodynamic parameters showed that the complex was more stable at lower temperatures...
Arabian Journal of Chemistry, 2019
2-Chloropyridine and Iodine monochloride form 1:1 n ? r * charge transfer complex which is confirmed by Benesi Hildebrand plot using UV-vis spectroscopy. Multiple Linear Regression Technique (MLRT) shows that 2-Chloropyridine-ICl complex is susceptible to medium effect in reference to different solvent parameters, at both the bulk and molecular levels. Dielectric constant (2), refractive index (n), Hansen parameter, Catalan parameter and Kamlet's p * values give good linear fit equations between experimental and calculated CT bands with R 2 values as high as 1. Polarizability effect on the CT band is examined using Buckingham and Lippert Mataga equation. Formation constant of the complex in different mediais found to be linearly dependent on Hansen solubility parameter. Computational analysis defends well the blue shift in polar medium observed for 2-Chloropyridine-ICl. NBO, NRT, and QTAIM analyses explain a shift from ionic character to covalent character in polar medium. It emphasises a stronger donor acceptor interaction in polar medium and thereby explains the experimentally observed blue shift. A logarithmic relation between the bond lengths of the bridging atoms and dielectric constant is proposed.
2004
The Complex formation reaction between iodine with tetrabutylammonium halides (TBAX) has been studied spectrophotometrically in chloroform solution at 25oC. Various aspects of the spectra of iodine in the presence of various concentration of different tetrabutylammonium halides have been discussed in terms of electronic specifications of iodine and halides. In the case of tetrabutylammonium iodide and at high concentrations of iodine, both 1:1 (I3 ) and 2:1 (I5 ) complexes have been formed. Formation constants of charge transfer complexes were evaluated from the computer fitting of the absorbance-mole ratio data and found to vary in the order: TBAI>TBABr>TBACl>TBAF. Introduction Investigation of polyhalide complexes has a long background [1] and various aspects of these complexes have been studied extensively. Examples are molecular orbital study [2], [3], spectrophotometric study in different solvents such as acetonitrile and dichloroethane [4], conductometric study in non...