Resonance Raman scattering by exciton polaritons in crystals of CuGaS2 under excitation with the 4880 and 4765 Å lines of an Ar+ laser at 9 K is studied. Lines of one-and two-phonon scattering of excitonic polaritons are found and studied. It is shown that the 1LO and 2LO phonons are arranged in accordance with their energies as the Stokes shifts move farther away from the excitation energy. 相似文献
Porphynns having covalently attached residues of azo dyes on the periphery of the molecule have been synthesized by the diazotization of tetraaminophenylporphynns and subsequent azo coupling of the diazonium salts with phenol, and with - and -naphthols. The possibility of - electron interaction of the two chromophoric systems has been studied.Ivanovo State Institute of Chemical Technology, Ivanovo Center, 153460.Translated from Khimiya Geterotsklicheskikh Soedinenii, No. 8, pp. 1045–1049, August, 1996. Original article submitted July 2, 1996. 相似文献
The behavior of bovine serum albumin as a function of the pH of the medium and the presence in the test systems of symmetrical and asymmetrical hydrophobic porphyrins was investigated. It was established that 4-[(tert-butoxycarbonylamino)acetamido]phenyl group favors stronger protein binding to porphyrin, and this effect enhances in an alkaline medium. Solubilization of protein by porphyrins leads to the fact that the particles are spherical in solution, the hydrodynamic radius of the protein globule reduced in an alkaline medium but in neutral medium, in contrast, increases. By IR spectroscopy it was shown that beta-structuring and the proportion of disordered coils of the polypeptide chain in an alkaline medium increases, because the complexability of the protein towards porphyrin is changes.
The formation of deprotonated forms of tetra(t-butyl)phthalocyanine ((H2tButPc) and octa(pentoxy)-phthalocyanine (H2OAmPc) in the system acetonitrile-1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) at 298 K was studied by the method of spectrophotometric titration. With increasing DBU concentration sequential formation occurs of both mono- and douby deprotonated forms. The introduction of pentoxy groups into the fused benzene rings leads to a significant decrease in the acidity of the tetrapyrrole macrocycle compared with the tert-butyl substitution. The interaction of douby deprotonated forms of the phthalocyanines with zinc diacetate leads to the formation of metal complexes, the chelation constant of the latter is shown to correlate with the acidity of NH-protons in the nucleus of the macrocycle. For the chelation of more acidic tetra(t-butyl)-phthalocyanine an equimolar concentrations of zinc diacetate is sufficient, while the less acidic octa(pentoxy)-phthalocyanine requires almost 6-fold excess. 相似文献
The mono-meso-allyloxy- and acrylamidophenylporphyrins were synthesized from the corresponding hydroxy- and aminophenylporphyrins. All the compounds were characterized by IR, UV-Vis, 1H NMR and mass spectra. 相似文献
The Raman scattering and IR reflectivity have been investigated for different crystal configurations. The contours of reflectivity spectra have been calculated. The angle dependence of polar vibrational modes in both reflectivity and Raman spectra have been investigated. The peculliarities of the transition from longitudinal mode to transverse one and vice versa both with and without changing of symmetry have been obtained. The phonon parameters and effective ionic charges of the anions and cations have been determined. It has been shown that there exists an effective ionic charge anisotropy of the oxygen and tellurium ions. 相似文献
Infrared reflectivity spectra of PbGa2S4 single crystals are measured at room temperature in the wavenumber range from 30 to 4000 cm−1 for the polarization directions E ∥ c and E ∥ b. The frequencies of 13 B1u modes and 11 B2u modes are derived from the spectra. The results are compared with previous studies and with lattice vibration data of ternary chalcopyrite and defect-chalcopyrite compounds. 相似文献
The influence of the deformation of the tetrapyrrole aromatic macrocycle and the electronic effects of substituents on the
kinetic parameters in the formation and dissociation reactions of cobalt complexes of porphyrins are discussed on the basis
of a study of the kinetics of the formation and dissociation of cobalt complexes with meso-phenyl octa(methyl)porphyrin derivatives: 5,10,15-triphehyl octa(methyl) porphyrin; 5,15-bis-(3′,5′-di-tert-butyl phenyl) octa(methyl)porphyrin; 5,10,15-tris-(3′,5′-di-tert-butyl phenyl) octa(methyl)porphyrin; and 5,10,15,20-tetrakis-(3′,5′-di-tert-butyl phenyl) octa(methyl)porphyrin in acetic acid and pyridine. 相似文献
p-(Alkoxybenzylidene)-p′-toluidines (ABTs) with 7, 8, and 10 carbon atoms in the alkyl moiety have been studied by wide-line 1H NMR and DSC. The thermotropic properties of these compounds have been studied in the temperature range 20–80°C, including main mesomorphic transformations of ABTs. The 1H NMR line shapes, widths, and second moments, as well as specific features of their temperature-induced changes, are discussed. The DSC data are compared with the character of mesomorphic transformations and 1H NMR data. The formation limits and ranges and stabilities of liquid-crystalline states of the ABT structure emerging on heating are determined. 相似文献
Exciton spectra are studied in CuGaXIn1−XS2 solid solutions by means of photoreflectivity and wavelength modulation spectroscopy at liquid nitrogen temperature. The exciton parameters, dielectric constants, and free carrier effective masses are deduced from experimental spectra by calculations in the framework of a model taking into account the spatial dispersion and the presence of a dead-layer. The crystal field and spin orbit valence band splitting is calculated as a function of X taking into account the energy position of excitonic lines. The energy band structure of CuGaXIn1−XS2 and CuGaXIn1−XSe2 compounds is derived from optical spectra at photon energies higher than the fundamental band gap. The energies of optical transitions are tabulated for X values from 0 to 1. 相似文献