Showing papers in "Spectroscopy Letters in 1997"
TL;DR: In this article, a simple and reliable method for the determination of trace amounts of famotidine, fluconazoie and ketoconazole in bulk powder and in their pharmaceutical dosage forms was investigated.
Abstract: The aim of this work was to investigate a simple and reliable method for the determination of trace amounts of famotidine, fluconazoie and ketoconazole in bulk powder and in their pharmaceutical dosage forms. Also to study the different factors affecting the sensitivity of the synchronous technique in order to improve the measurement The sample was prepared in methanol in case of famotidine and ketoconazole, and in water, after dissolution in methanol, in case of fluconazoie. The fluorescence intensity was recorded at 384 (ex. at 284 nm), 285 (ex. at 255 nm) and 364 nm(ex. at 239 nm) for famotidine, fluconazole and ketoconazole respectively. The calibration curves were linear over the concentration ranges 15 50, 0. 20–10 and 0. 02–0. 4 μg/ml for famotidine, fluconazole and ketoconazole respectively.
39 citations
TL;DR: In this article, the IR spectra of a series of substituted salicylaldehyde and 2-hydroxy-naphthaldehyde Schiff bases were used to investigate enol-keto tautomeric equilibrium.
Abstract: Infra-Red spectra of a series of substituted salicylaldehyde and 2-hydroxy-naphthaldehyde Schiff bases were used to investigate enol-keto tautomeric equilibrium. Two model compounds, namely, salicylidinaniline and naphthylidinequinolineamine Schiff bases were used to represent the enol and keto forms, respectively. From the IR spectra of the model compounds it was possible to assign the IR absorption for the C=O and the C=N groups in both the keto and the enol form. It was also possible to assign other absorptions which were either specific to the keto or the enol forms. Specific pattern were observed for all the studied compounds.
39 citations
TL;DR: Using cefotaxime sodiume as model drug with esterfunctional group, it was shown that proposed method gives equally acurate and precise results even in the presence of ester functional group.
Abstract: Cephalexin, cefixime, ceftriaxone and cefotaxime were determined spectrophotometrically in the pure form and in pharmaceutical formulations by using ferrihydroxamate method. Reaction optimization with respect to reaction time and temperature has been investigated. Influence of the presence of ester functional group on the determination of cephalosporins as s-lactams under conditions optimized was evaluated. Using cefotaxime sodiume as model drug with ester functional group, it was shown that proposed method gives equally acurate and precise results even in the presence of ester functional group.
39 citations
TL;DR: In this paper, a relation between symmetric V1 and asymmetric v3 O-U-O frequencies independent on the masses of oxygen (Mo) and uranium (Mu) atoms was proposed.
Abstract: New series of uranyl complexes derived from 7-formyl-8-hydroxy quinoline with hydrazine hydrate (HL1), methyl hydrazine (HL2), 1,2-diaminoethane (HL3), 1,2-diaminobenzene (HL4) and 2-aminopyridine (HL5) have been prepared and characterized by elemental analyses, (1H NMR and 13C NMR, electronic and vibrational spectra) and different physical techniques. The magnetic and spectral data suggest a distorted octahedral structure for all complexes. The labile EtOH molecule in compounds (5), (7) and (9) is equatorially bonded to the uranium ion and its hydrogen is bonded to the axial oxygen of the uranyl moiety. The ligands contain intramolecular hydrogen bonds. The FU-O(mydn/Ao) and the bond length RU-O(Ao) of the bond were calculated from the IR data. In the present work it has been proposed a novel relationship between symmetric “V1” and asymmetric “v3” O-U-O frequencies independent on the masses of oxygen (Mo) and uranium (Mu) atoms.
39 citations
TL;DR: In this paper, a new 2′-hydroxychalcone and flavone derivatives have been synthesised and their [1H] and [13C] NMR spectra were assigned by the application of COSY and HETCOR experiments and allowed the discussion of structural aspects.
Abstract: New 2′-hydroxychalcone and flavone derivatives have been synthesised. Their [1H] and [13C] NMR spectra were assigned by the application of COSY and HETCOR experiments and allowed the discussion of some structural aspects. It was shown on the basis of NOE experiments some configurational and conformational features of both type of compounds.
27 citations
TL;DR: In this paper, the siting problem of transfer stations in a large scale metropolitan region is decomposed into two different levels and an analytical approach encompasses a preliminary screening procedure using the Geographical Information System (GIS) and an optimization analysis by a mixed integer programming model, in which the screening of initial candidate sites and the optimization of a solid waste collection, recycling, treatment, and disposal system is used to direct waste generation to existing or proposed transfer stations, treatment plants and disposal facilities at minimum cost.
Abstract: System analysis for solid waste management currently receives wide attention from both economic and environmental planners because of their complexity during the coordination of various management strategies This paper deals with the development and application of an operational solid waste management model through a hierarchical approach, in which the siting problem of transfer stations in a large scale metropolitan region is decomposed into two different levels This analytical approach encompasses a preliminary screening procedure using the Geographical Information System (GIS) and an optimization analysis by a mixed integer programming model Four criteria are employed in the screening of initial candidate sites and the optimization of a solid waste collection, recycling, treatment, and disposal system is used to direct waste generation to existing or proposed transfer stations, treatment plants and disposal facilities at minimum cost A case study in Taiwan shows that the optimal siting str
21 citations
TL;DR: In this paper, the rotational analysis of the four bands have been carried out for the first time for MoO and WO molecules and new features have been discovered, which has been referred to new electronic transition.
Abstract: Absorption electronic spectra of MoO and WO molecules have been investigated by a intracavity laser technique in the region 550–800 run. New features have been discovered. As for MoO molecule the rotational analysis of the four bands have been carried out for the first time. Two of these bands were referred to 0–0 transitions arisen from the new (probable triplet) low-lying electronic state, two other bands were referred to transitions arisen from excited components of X5II ground state. As for WO molecule the rotational analysis of 0–0 and 1–0 bands represented A-X and B-X systems have been carried out for the first time. The new band has been discovered which has been referred to new electronic transition. Molecular constants of new states of both molecules studied have been evaluated.
18 citations
TL;DR: D Diagnostics of experimental zinc intoxication by industrial emission from the zinc and copper factory on the basis of accumulation and distribution of Zn, Cu, Fe, Mo, Se, As, Cd and Pb in the liver, kidneys, spleen, musculature, uterus, ovaries, chorioidea of eye and bones in seven experimental and five control sheep are described.
Abstract: Diagnostics of experimental zinc intoxication by industrial emission from the zinc and copper factory on the basis of accumulation and distribution of Zn, Cu, Fe, Mo, Se, As, Cd and Pb in the liver, kidneys, spleen, musculature, uterus, ovaries, chorioidea of eye and bones in seven experimental and five control sheep is described. A daily intake of Zn from industrial emission was 6158.07 mg/an experimental animal. The first animals died of zinc intoxication on d 42 and the last one on d 58 of the experiment. The highest concentration of zinc in experimental animals died of zinc intoxication was in the liver dry matter (1167.3 ± 314.1 mg.kg−1) and in the kidneys (1049.5 ± 283.7 mg.kg−). Significantly higher Zn content compared with the control sheep was confirmed in the experimental ones in the liver, kidneys, ovaries and eye chorioidea (p < 0.01). The liver, kidneys, uterus were the organs with the highest Cu accumulation. The highest Fe accumulation was found in the spleen, kidneys and liver. Di...
18 citations
TL;DR: Using the product operator technique, an analytical description of heteronuclear 2D-J resolved NMR spectroscopy for a weakly coupled IS n (I=I/2, S=1, n = 1, 2, 3, 4, 5, 6, 7, 8, 9) spin system is presented in this paper.
Abstract: Using the product operator technique, an analytical description of heteronuclear 2D-J resolved NMR spectroscopy for a weakly coupled IS n (I=I/2, S=1, n=1, 2, 3) spin system is presented As a pulse sequence, the most commonly used one, the gated decouple sequence, is used The obtained analytical results were found to be in good agreement with the experimental ones
17 citations
TL;DR: Using di-2-pyridil ketone benzoilhydrazone (DPKBH) was used in excess in order to coordinate Ni(II) and the highest sensitivity was obtained in 50% v/v ethanol solutions when ammonium acetate buffer was added to maintain pH ≥ 6 as discussed by the authors.
Abstract: Nitrogen-containing heterocyclic hydrazones have been used as analytical reagents, mainly to metallic ion spectrophotometric determinations in natural water samples. Using the reagent di-2-pyridil ketone benzoilhydrazone (DPKBH) we have developed a spectrophotometric method for the determination of Ni(II) in samples of several sources. DPKBH was used in excess in order to coordinate Ni(II) and the highest sensitivity was obtained in 50% v/v ethanol solutions when ammonium acetate buffer was added to maintain pH≅6. Analysis for Ni(II) in natural water is frequently performed by EAAS following preconcentration involving solvent extraction. While these methods are sensitive, they also require relatively expensive instrumentation and are generally time-consuming. In contrast, the advantages of the proposed method are the use of simple instrumentation and the possibility of its application in the field. The method is fast, shows high sensitivity, good precision and several samples can be prepared and ...
17 citations
TL;DR: In this paper, the change of vHX frequencies in hydrogen-bonded complexes of different structure is analyzed and the dependence of the proton-donor (proton-acceptor) ability on the bend of the angle adjacent to the hydrogen bond is found.
Abstract: The literature data on the change of vHX frequencies in hydrogen-bonded complexes of different structure are analysed. It is shown that the earlier found frequency dependencies can have a simple physical explanation. It consists in the fact that the XH-bond of any molecule, apart from its proton-donor and proton-acceptor properties, also has certain transmission abilities. It means that when hydrogen bonds are conjugated, to the proton-donor ability of any XH-group is always added a certain part (specific for this XH-group) of the proton-donor ability of the molecule, in relation to which this XH-group acts as a proton-acceptor. Similarly, the proton-acceptor property of XH-group is increased by a certain part (specific for this XH-group) of the proton-acceptor ability of the molecule, in relation to which this XH-group acts as the proton-donor. The dependence of the proton-donor (proton-acceptor) ability on the bend of the angle adjacent to the hydrogen bond is found.
TL;DR: In this article, the Diels-Alder adduct of N-carbamoylmaleimide with phencyclone was investigated and the data for the adduct, 2, were interpreted as being consistent with essentially slow exchange limit (SEL) spectra with respect to rotation about the C(sp2)-C(sp3) bonds to the unsubstituted bridgehead phenyls, and slow rotation on the NMR timescale for the amide NH2 group.
Abstract: Analysis of NMR spectra of selected model compounds can be of great value in understanding aspects of hindered rotation and magnetic anisotropy in drugs and other compounds of much intrinsic importance. One- and two- dimensional 1H NMR (300 MHz) and 13C NMR (75 MHz) studies have been performed at ambient temperatures on the Diels-Alder adduct of N-carbamoylmaleimide with phencyclone, 1. The data for the adduct, 2, are interpreted as being consistent with: a) essentially slow exchange limit (SEL) spectra with respect to rotation about the C(sp2)-C(sp3) bonds to the unsubstituted bridgehead phenyls, b) slow rotation on the NMR timescale for the amide NH2 group, and c) fast rotation about the amide N-CONH2 bond to the ring nitrogen. The assigned endo stereochemistry for adduct 2 and the conclusions regarding bond rotation rates are based on numbers of observed NMR signals and magnetic anisotropic effects. Full 1H NMR spectral assignments and preliminary 13C assignments are presented.
TL;DR: In this paper, the infrared and Raman spectra of tetracalcium phosphate (Ca4P2O9) were measured and interpreted on the basis of factor group analysis.
Abstract: The infrared and Raman spectra of tetracalcium phosphate (Ca4P2O9) were measured and interpreted on the basis of factor group analysis. Factor group splitting can be noted for the various internal vibrational modes of the PO4 3- ion. However, a fewer number of factor group-split bands can be seen than predicted because of either the weak intensities of these bands or the convolution of such bands for the various internal modes of vibration.
TL;DR: In this paper, a rapid and convenient spectrophotometric method is described for the quantitative determination of some of Cephalosporines Cefadroxil, I Cephradine II and Cefaclor III.
Abstract: A rapid and convenient spectrophotometric method is described for the quantitative determination of some of Cephalosporines Cefadroxil, I Cephradine II and Cefaclor III. The proposed method depends upon the conversion of these compounds to the corresponding piperazine-2,5 dione derivatives by heating in an alkaline sorbitol-zinc ion solution for 10—25 minutes at 90°C and subsequent treatment of these derivatives with 0.1 N sodium hydroxide to obtain highly absorbing products with λmax at 345 nm for I & II and at 334 nm for III using zero order absorption curve. Using first derivative spectrum (D1) for III the λmax is at 362 nm. The method was found to be free of the interference from polymerization and other degradation products. Its application to assess the stability of the Cephalosporines was demonstrated. Verification of Beer's Law showed lincarity at concentrations of 12.5-87.5 μg ml−1, 12.5-125 μg ml−l and 6.7-66.7 μg ml−1 for I, II and III respectively with mean accuracies 100.37 ± 0.72%, ...
TL;DR: In this article, the 2,2,6,6-tetramethyl-I-piperidinyloxy free radical (TEMPO) was used as a probe to study the changes in hydrogen bonding between the phenolic OH group and the ON group of the radical by means of NMR and EPR.
Abstract: The 2,2,6,6-tetramethyl-I-piperidinyloxy free radical (TEMPO) was used as a probe to study the changes in hydrogen bonding between the phenolic OH group and the ON group of the radical by means of NMR and EPR. 13C NMR contact shifts induced by TEMPO were measured for five phenols. Formation of intermolecular hydrogen bond between a phenol and TEMPO molecule causes noticeable increase of 14N hyperfme coupling constant in the radical and appearance of negative spin density on carbon nuclei of C-OH fragment in the phenol.
TL;DR: In this article, one-and two-dimensional 1H and 13C NMR at 300 and 75 MHz, respectively, at ambient temperatures in different solvents were used to characterize the Diels-Alder adduct.
Abstract: 4-Methyl-1, 2, 4-triazoline-3, 5-dione was produced by lead tetraacetate oxidation of 4-methylurazole and allowed to react with phencyclone, 1-The resulting Diels-Alder adduct, 2, has been characterized by one-and two-dimensional 1H and 13C NMR at 300 and 75 MHz, respectively, at ambient temperatures in different solvents. The NMR data are consistent with hindered rotation of the bridgehead unsubstituted phenyl groups about the C(sp2)-C(sp3) bonds, based on numbers of absorption signals in the 1H and 13C NMR aryl region, together with magnetic anisotropic effects in the 1H spectrum. The spectral simplicity suggests further that stereochemistry at the ring junction nitrogens involves only a single isomer or very rapidly interconverting “exo”/“endo” isomers (if the ring junction nitrogens are pyramidalized).
TL;DR: In this paper, the spectral properties of M(1,6-diaminohexane)Ni(CN)4˙ C6H6 (M-Co, Ni or Cd) are reported.
Abstract: Infrared spectra of M(1,6-diaminohexane)Ni(CN)4˙ C6H6 (M-Co, Ni or Cd) are reported. The spectral data suggest that the compounds are similar in structure to Cd(1,6-diaminohexane)Ni(CN)4˙m-Toluidine and have Hofmann-diam-type structure.
TL;DR: In this paper, a simple spectrophotometric method for the determination of niclosamide in pure and dosage forms has been developed based on the reduction of the nitro group in niclosamides to the amino group by heating in a water bath a mixture of niclosamide solution in 95% ethanol, zinc powder and dilute hydrochloric acid for 15 minutes.
Abstract: A simple spectrophotometric method for the determination of niclosamide in pure and dosage forms has been developed. The proposed method is based on the reduction of the nitro group in niclosamide to the amino group by heating in a water bath a mixture of niclosamide solution in 95% ethanol, zinc powder and dilute hydrochloric acid for 15 minutes. The cold and clear filtrate reacts with p-benzoguinone, where a compound of pink colour is obtained which absorbs maximally at 506 nm. The stoichiometry of the proposed method and the possible pathway of the reaction is presented. The method determines from 12.5–125 μg/ml of niclosamide with mean percentage recovery of 100.07 ± 0.707. The suggested method was applied to Niclosan and Yomesan tablets and its validity was ascertained by standard addition technique.
TL;DR: In this article, the 1: 2 stoichiometry of the (TACTD)-acceptor was derived based on elemental analysis and infrared spectra of the solid CT-complexes along with the photometric titration curves for the reactions in CHCl3.
Abstract: The reactions of π-electron acceptors such as 1-chloro-2,4,6-trinitrobenzene (picryl chloride), 7,7′,8,8′-tetracyanoquino-dimethane (TCNQ), tetrachloro-p-benzoquinone (chloranil) and tetra-cyanoethylene (TCNE) with the cyclic polyamine base 1,4,8,11-tetraazacyclotetradecane (TACTD) have been investigated in CHCl3 solvent. The data indicate the formation of the CT-complexes with the general formula [(TACTD) (acceptor)2]. The 1: 2 stoichiometry of the (TACTD)-acceptor was based on elemental analysis and infrared spectra of the solid CT-complexes along with the photometric titration curves for the reactions in CHCl3. The formation constants (K) for the CT-complexes are shown to be strongly dependent on the type and structure of the acceptor.
TL;DR: In this paper, the adsorption state was characterized by Foruier transform surface-enhanced Raman scattering spectroscopy (FT-SERS) and the results indicated that adsorbed molecules stand on the surface in tilting conformation.
Abstract: 4-Aminophenyl ammonium dithiocabamate can easily be chemisorbed on chemically deposited silver film and HNO3 etching silver to form monolayer molecular films. The adsorption state was characterized by Foruier transform surface-enhanced Raman scattering spectroscopy (FT-SERS). The results indicated that the adsorbed molecules stand on the surface in tilting conformation.
TL;DR: In this article, 3,3a,4,5,6,7-hexahydro-3-trichloromethyl[2,1]benzo isoxazole (1), obtained from the cyclization of trichloroacetyl cyclohexanone with hydroxylamine, is reported.
Abstract: 1H and 13C NMR data, AMI calculations and X-ray diffraction in 3,3a,4,5,6,7-hexahydro-3-trichloromethyl[2,1]benzo isoxazole (1), obtained from the cyclization of trichloroacetyl cyclohexanone with hydroxylamine, are reported. 1H and 13C NMR data shown that only one pair of the diastereoisomers was obtained and the AMI calculations indicated that 1a (3S3aS/3R3aR) is 2.63 kc:al.mol−1 more stable than 1b (3S3aR/3R3aS). The X-Ray diffraction data confirmed that only the structure 1a was obtained. Crystals of 1 (C8H10Cl3NO2, Mr = 258.52) were obtained from acetone/n-hexane solution. The compound crystallizes in the monoclinic space group P21/c with the cell dimensions a = 10.153(2), b = 8.271(2) and c = 14.225(3) A, β = 103.8(3)°, V = 1160.0(4) A3, Z= 4, Dcalcd. = 1.480 Mg/m3, λ(MoKα) = 0.71073 A, = 0.764 mm-1, F(000) = 528, T= 293(2) K, R = 7.31 % and Rw = 17.91 % for an F 2 refinement on unique data with 2082 reflections and 1994 independent (Rint = 6.70%) were collected.
TL;DR: In this article, the spectral properties of free and bound H-bonded molecules of substituted anilines in solutions were analyzed in the region of stretching and deformational vibrations of amino group.
Abstract: Infrared spectra of free and bound with different proton acceptors in 1:1 and 1:2 complexes H-bonded molecules of 3, 5-dichloroaniline, 3, 5-dibromoaniline, 2, 3, 5, 6-tetrafluoroaniline, 4-methoxytetrafluoroaniline, pen-tafluoroaniline, 4-nitro-anihne, 2, 6-dichloro-4-nitroaniline, 4-nitrotetraflu-oroaniline and 4-aminotetrafluoropyridine were studied in the region of stretching and deformational vibrations of amino group. Spectral characteristics of absorption bands of free and bound H-bonded molecules of substituted anilines in solutions were determined. With regard to dynamic and electrooptical non-equivalence of amino group NH-bonds in free and bound H-bonded molecules of anilines the solution of vibrational and electrooptical tasks was found. The valent angles γ (HNH) and the dynamic and electrooptical characteristics of amino group NH-bonds were determined. Equilibrium constants monomer-complex were calculated for 1:1 H-bonded complexes. The influence of the position, number and individual...
TL;DR: The use of lasers in analytical atomic spectrometry is discussed in this paper, where the major uses of lasers are described, i.e., in laser excited atomic fluorescence, laserenhanced ionization, laser-induced breakdown emission and laser sampling.
Abstract: This paper discusses the use of lasers in analytical atomic spectrometry. Following a brief discussion on the properties of lasers that attract analytical atomic spectroscopists, the major uses of lasers, i.e., in laser excited atomic fluorescence, laser-enhanced ionization, laser-induced breakdown emission and laser sampling are described, particularly its application to real samples. A very brief description of theory or basic principles, laser used in experimental set up and selected and representative applications are presented. Finally, the potential future of the laser in analytical atomic spectrometry will be discussed. 1 Presented, in part, at Pittcon 97, Atlanta, Georgia, 16–21 March, 1997
TL;DR: In this paper, the Spermine phosphate hexahydrate was found to be adsorbed to the metal surface through nitrogen and oxygen atoms of the molecules, showing the protonation of amino and imino groups indicated by the presence of HPO4 2- ion.
Abstract: FTIR, Raman and SERS spectra of spermine phosphate hexahydrate have been recorded and analysed. Vibrational spectra show the protonation of amino and imino groups indicated by the presence of HPO4 2- ion. The molecule is found to be adsorbed to the metal surface through nitrogen and oxygen atoms of the molecules. Distortion of the HPO4 2- ion, change of symmetry of the molecule due to chemisorption and the enhancement in intensity of the amino group vibrations are discussed.
TL;DR: In this paper, the anionic derivatives of a series aliphatic, arylaliphatic and aromatic compounds containing amide group were investigated by means of infrared spectroscopy.
Abstract: The anionic derivatives of a series aliphatic, arylaliphatic and aromatic compounds containing amide group were investigated by means of infrared spectroscopy. The stretching vibration frequencies of the amide C=O, the ketone C=O and the N-C(Ph) in the N-anions of the studied compounds were assigncd: the amide C=O shifts 76-180 cm−1 downward depending on the substituents; the band intensity increases 2.5-3 times. It was found an excellent correlation between the carbonyl stretching vibration frequencies of the studied N-anions with the Hamrnett CJ constants of the substituents.
TL;DR: In this paper, the electronic absorption spectra of trans-[Cu(sap)2], where (Hsap = salicylidene-o-aminopyridine (Schiff base)), were measured in various solvents at room temperature.
Abstract: The electronic absorption spectra of trans-[Cu(sap)2], where (Hsap = salicylidene-o-aminopyridine (Schiff base)), were measured in various solvents at room temperature. The d-d transition energies is used to derive the angular overlap model (AOM) parameters in C2h symmetry. The experimental curves were resolved by Gaussian analysis. A comparison of the spectra, ligand field parameters and stereochemistries in various solutions was made. The effect of the solvents upon the σ, π-bonding, and bite angle of the bidentate ligand is discussed.
TL;DR: In this article, a vibrational study of the local anesthetic procaine hydrochloride in the solid state and in aqueous solution was carried out, and the structure of the procaine cation was determined using the AM 1 semi-empirical method.
Abstract: A vibrational study of the local anesthetic procaine hydrochloride in the solid state and in aqueous solution was carried but. Assignment of the amino groups was performed using deuterated and non-deuterated samples. All the bands in the spectra were identified and assigned. The structure of the procaine cation was determined using the AM 1 semi-empirical method. A comparison with crystallographic data was made. The frequencies and intensities of the vibrations were also computed using AM1. Vibrational scale factors were employed in the AM1 calculations.
TL;DR: In this paper, a rapid and specific proton magnetic resonance (PMR) spectroscopic method was developed for determining ranitidine hydrochloride in tablets using 2-Choloroacetophenon as the internal standard.
Abstract: A rapid and specific proton magnetic resonance (PMR) spectroscopic method was developed for determining ranitidine hydrochloride in tablets. 2-Choloroacetophenon was used as the internal standard and DMSO-d6 served as the PMR solvent. The concentration of drug per unit dose was calculated from the integration values for the resonance signals of ranitidine hydrochloride at 4.32 δ ppm and int. st. at 5.19 δ ppm. The method using commercial products gave comparable results to those obtained by the methods of UV spectroscopy and USP XXIII.
TL;DR: In this paper, a method to determine electrical mobility of charge carriers containing paramagnetic elements is presented, where the motion-induced phase shift of the transverse magnetization component is observed by magnetic resonance (MR).
Abstract: A method to determine electrical mobility of charge carriers containing paramagnetic elements is presented. The motion-induced phase shift of the transverse magnetization component is observed by magnetic (nuclear or electron) resonance (MR). In fluid media, this method can determine the type of carriers and respective motion, lifetimes distribution, thermal and frequency dispersion of the mobility, translational relaxation rate and activation energies of these processes. ∗) Address for correspondence and reprints.
TL;DR: In this article, steady state and time-resolved decay analysis techniques have been adopted to study the excited state proton transfer (ESPT) reaction of carbazole (CAZL) in three aqueous micellar solutions, namely, cetyltrimethylammonium bromide (CTAB), sodium dodecyl sulphate (SDS), and triton X-100 (TX) in the absence as well as in the presence of urea.
Abstract: Steady state as well as time-resolved decay analysis techniques have been adopted to study the excited state proton transfer (ESPT) reaction of carbazole (CAZL) in three aqueous micellar solutions, namely, cetyltrimethylammonium bromide (CTAB), sodium dodecyl sulphate (SDS) and triton X-100 (TX) in the absence as well as in the presence of urea. For all the micellar systems studied, multiple critical micellar concentrations (CMCs) have been observed. Urea is found to inhibit the micellisation process. Light has been thrown on the mode of action of urea. It has also been shown that urea expels the fluorophore molecule from the micellar periphery to the bulk aqueous phase.