Overtone spectroscopy of chlorine substituted benzene derivatives

The absorption spectra of di-, tri- and tetra-derivatives of chlorobenzene have been studied in their pure form in the spectral range 400-20,000 cm(-1). A large number of bands associated with the fundamental, the overtones and the combination frequencies of C-H stretching mode have been observed. Vibrational frequencies, anharmonicity constants and dissociation energies, for the C-H stretch vibrations for the six molecules have been determined using local mode model. The C-H stretch frequencies obtained from experiments are compared with the corresponding frequency determined theoretically using RHF and DFT methods with same 6-31+G* basis set. This information has been used for the assignment of several combination bands as well as some weak overtone bands. Effect of hydrogen atom substitution by chlorine atom has been studied by measuring changes in the vibrational frequency of the C-H stretching mode and the C-H bond length. Frequency changes have been well correlated with the change in charge density on carbon as well as chlorine atoms.     

Overtone spectroscopy of butanol

Overtone spectra of CH and OH stretching vibrations in normal, secondary and tertiary butanol have been studied. A large number of combination and overtone bands, along with the fundamentals have been measured and assigned in the three cases. These data have been used to obtain the vibrational frequency, anharmonicity constant and dissociation energy for the CH and OH stretch motions in the respective molecules. Effect of dilution on the OH fundamental frequency in n-butanol causes a blue shift.     

Anionic polymerization of styrene sulfonic acid derivatives

As a preliminary to the preparation of block copolymers of p-styrene sulfonic acid and isoprene, anionic polymerization of several derivatives of the former was investigated. Radical anions of naphthalene were used as the initiator for this study, in which the effects of polymerization variables including counterion, temperature, monomer and initiator concentrations, and solvent were investigated. Synthesis techniques were modified to obtain monomers of sufficient purity for anionic polymerization of n-propyl, isopropyl, and methyl styrene sulfonates were successfully initiated, but only a limited degree of polymerization could be achieved under a wide variety of polymerization conditions. It is tentatively suggested that the living polymeric anions become dormant owing to a complexation between the anion and nearby sulfonate groups on the polymer coil.     

Overtone spectra of aniline derivatives

Overtone spectra of 2-ethylaniline, N-methylaniline, N-ethylaniline, N,N-dimethylaniline and N,N-diethylaniline have been studied in 2500-15000 cm(-1) region. Vibrational frequency and anharmonicity constants for aryl/alkyl C-H stretch and N-H stretch vibrations have been determined. The effect of substitution of C(2)H(5) group on the ortho position in the ring and CH(3)/C(2)H(5) at the positions of the H-atom in NH(2) group has been studied in these molecules. It is noted that the aryl C-H stretching frequency and the N-H stretching frequency is appreciably increased due to the replacement of H in NH(2) group by CH(3)/C(2)H(5). These experimental observations are well supported by theoretical calculations for charge density on N-atom using molecular orbital AM(1) method.     

Overtone spectroscopy of isobutane at cryogenic temperatures

The spectra of the fundamental and overtones of the C---H stretches of (CH₃)₃CH have been measured in liquid argon solutions at 90 K and for the pure liquid sample at 135 K. Absorptions in the visible were obtained with a low temperature cell and a resonant continuous wave laser technique with acoustic detection. Absorptions in the IR and near-IR were observed with a Fourier transform spectrophotometer. Comparison is made between the absorption bands in gas phase, liquid argon solution, and liquid phase isobutane. The spectra of isobutane in solution show improved resolution of the vibrational bands with respect to the room temperature gas phase bands and the pure liquid bands at 135 K. To interpret the experimental results, overtone transitions are described in terms of the local mode model. A harmonically coupled anharmonic oscillator (HCAO) model was used to determine the overtone energy levels and assign the absorption bands to vibrational transitions. Ab initio molecular orbital calculations of geometries and vibrational frequencies were also performed.     

Overtone surface vibrational spectroscopy of zeolite-encaged molecules

Overtone spectra of adsorbed molecules yield information complementary to that obtained from the fundamentals, (i) enabling to follow the formation and development of bands up to high coverages, (ii) facilitating the assignment of bands, (iii) giving indication to the processes governing the bandshape and (iv) in case of diatomics making feasible the determination of changes of the constants of intramolecular potential, and so of the dissociation energy. The practicability is demonstrated by diatomics adsorbed in Mg²⁺-exchanged zeolite A.     

Overtone spectroscopy of C-H ethyl stretches of 1-butyne

Room-temperature photoacoustic (PA) spectra and jet-cooled action spectra of the first to third overtone regions of the ethyl C-H stretches in vapor phase 1-butyne, CH3CH2C[Triple Bond]C-H, were measured. Both the PA and action spectra exhibit a complex multiple peak structure being better resolved and more pronounced in the latter, due to inhomogeneous structure reduction. The observed manifolds were analyzed in terms of a simplified joint local-/normal-mode (LM/NM) model accounting for two types of C-H stretches (methyl and methylene) and for Fermi resonances between stretches and deformations. The retrieved parameters, used for calculation of the eigenstates, come from the best-fit parameters based on the diagonalization of the vibrational Hamiltonian in the LM/NM basis. The parameters were obtained by comparing the eigenvalues and the sum of the squares of the expansion coefficients of the eigenvectors of the C-H stretches of methyl and methylene to the action spectra peak positions and intensities, respectively. This approximate model vibrational Hamiltonian is proposed to explain most observed spectral features, corresponding to C-H stretch bands and to combinations of C-H stretches and deformations, indicating the importance of the Fermi resonance. The model was also applied to calculate the dynamics of the C-H stretching modes resulting from coupling with the deformations, implying rapid initial state decay on subpicosecond time scale. Decays of several picoseconds were found for complete transfer of probability from the initially prepared state of methylene and methyl to the counterpart LM states.     

Enantiospecific synthesis of substituted 1-norbornanesulfonic acids and 1-norbornanesulfenic and sulfonic acid derivatives

New homochiral 1-norbornanesulfenic and sulfonic acid derivatives 2–7, as well as the sulfonic acids 8, are easily synthesised starting from 2-methylene-1-norbornylthiotriflates 1. This new class of homochiral bridgehead thiosulfonates was prepared by us from naturally occurring (+)-camphor and (−)-fenchone. Nucleophilic substitution at the sulfenyl sulfur atom is the key step for this synthetic strategy.     

Multinuclear and two-dimensional NMR spectroscopy of monoazo derivatives of chromotropic acid

By the use of one-dimensional (¹H,¹³C, and¹⁵N) and two-dimensional NMR spectra (H,H-COSY, H,C-COSY, and NOESY), it has been established that the phenylazo derivative of chromotropic acid in DMSO has a quinonehydrazone structure; under normal conditions, there is no azo-quinonehydrazone tautomerism. Spectral evidence has been found for the distribution of intramolecular hydrogen bonds.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2530–2535, November, 1989.     

Synthesis of new monoterpene sulfonic acids and their derivatives

The oxidation of monoterpene thiols with chlorine dioxide afforded new water-soluble sulfonic acids and their derivatives (sulfonothioates and sulfonyl chlorides). The reaction of terpene thiols with ClO₂ gave the corresponding trisulfides. Sulfonothioates with a pinane skeleton showed antibacterial and antifungal activity.     

Overtone spectroscopy and dynamics in monodeuteroacetylene (C2HD)

Complementary experimental, ab initio and dynamical investigations are reported on monodeuteroacetylene, C₂HD ( ¹Σ⁺). All experimental spectroscopic results previously reported in the literature on C₂HD, i.e. from 500 to 16000 cm⁻¹ are gathered. New results are included, which are obtained from the analysis of absorption data recorded with a Fourier transform interferometer at high resolution between 4600 and 9000 cm⁻¹. The presence of numerous weak bands along the whole spectral range is analysed in terms of systematic anharmonic couplings. The entire set of energy data is then used to produce thirty-five vibrational frequencies and anharmonicities from a fit of the vibrational energies to a Dunham-type expansion, and the vibrational level density is extrapolated, up to higher energy. One- and two-dimensional potential energy and dipole moment surfaces refined from new ab initio results are fitted to a selected set among those experimental data, associated to the stretch overtones. The iterative procedure involving an original package of computer programs is described. The evolution of the overtone intensities of the CH and CD stretches, up to η = 4, is interpreted on that basis in terms of electric and mechanical anharmonicity contributions. Eventually, dynamical aspects are studied thanks to the newly introduced vibrograms, which allow to obtain the time recurrences of the vibrational dynamics. Using the Gutzwiller and Berry-Tabor trace formulas, these vibrational recurrences are semiclassically assigned to periodic orbits of the classical Hamiltonian given by the Dunham expansion.     

Covalently linked ethylmercaptophenyl sulfonic acid and ethylmercaptobenzyl sulfonic acid silica materials—Synthesis and catalytic activity

New covalently linked sulfonic acid modified silicas have been formed and characterised and their catalytic Brönsted activity evaluated. Thus phenylmercaptoethyltrimethoxysilane, (MeO)₃SiCH₂CH₂SC₆H₅ and benzylmercaptoethyltrimethoxysilane, (MeO)₃SiCH₂CH₂SCH₂C₆H₅, were used to prepare the corresponding T-functional silica derivatives silica  CH₂CH₂SC₆H₄-4-SO₃H and silica  CH₂CH₂SCH₂C₆H₄-4-SO₃H by grafting on commercial silica, followed by sulfonation of the aryl group. Solid-state NMR, DTA and surface area characteristics of the materials are reported. The mercaptophenylsulfonic acid materials are thermally robust highly efficient solid catalysts for a range of transformations including, esterification, etherification and carbonyl group protection. An apparent pore size effect on rate of conversion was observed. The mercaptobenzylsulfonic acid materials were comparatively unstable.     

Synthesis of polybenzimidazoles with sulfonic acid groups

2-Sulfoterephthalic acid (STA) and disulfoisophthalic acid (DSIA) were synthesized through the sulfonation and the oxidation of m- and p-xylene. The polycondensation reactions of STA and DSIA with aromatic tetraamines gave polybenzimidazoles which contained one or two sulfonic acid groups for each repeating unit. The polymer obtained was soluble in sulfuric acid, some organic solvents, and aqueous strong alkaline solution. The polymers were stable up to 400°C, but they gave polybenzimidazoles above 400°C by eliminating sulfonic acid groups, instead of ring closure.     

Effect of the sulfonic acid group on copolymers of aniline and toluidine with m‐aminobenzene sulfonic acid

This article describes the results of the preparation and characterization of self‐doped conducting copolymers of aniline and toluidine with m‐aminobenzene sulfonic acid. The copolymers have an intrinsic acid group that is capable of doping polyaniline. Spectroscopic, morphological, and electrical conductivity studies have provided insight into the structural and electronic properties of the copolymers. The differences in the properties of polyaniline and polytoluidine due to the sulfonic acid ring substituent on the phenyl ring are discussed. The scanning electron micrographs of the copolymers reveal regions of sharp‐edged, needle‐shaped structures, whereas the X‐ray diffraction patterns show that the copolymers are relatively more crystalline in nature. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 4065–4076, 2002     

Thermodynamics of dinonylnaphthalene sulfonic acid (HD)

The effect of temperature on the extraction of the trivalent actinides Am³⁺, Cm³⁺ and Cf³⁺ with the liquid cation exchanger dinonylnaphthalenesulphonic acid (HD) in toluene is studied. The different thermodynamic functions of this system are determined from the experimental results. It is found that the free energy variation for the extraction of these metal ions by HD is mainly determined by the entropic terms arising from the hydration-dehydration process of the exchanged ions.     

Microdetermination of alkoxyl groups in sulfonic acid esters

Summary It was shown that the developed modification of the Zeisel-Vieböck method can be used for the microdetermination of the alkoxyl groups present in sulfonic acid esters. A mixture of potassium iodide and orthophosphoric acid is used to decompose the alkoxy compound.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimisheskaya, No. 7, pp. 1288–1289, July, 1965