Resonance Raman scattering by excitonic polaritons in CuGaS2

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.     

Synthesis of porphyrins with reactive groups on phenyl rings. 8. Azo dyes on tetraphenylporphyrins

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.     

Effect of pH on Albumin Binding with Hydrophobic Porphyrins

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.

     

Formation of phthalocyanines deprotonated forms and their interaction with Zn Ions in the system 1,8-diazabicyclo[5.4.0]undec-7-ene-acetonitrile at 298 K

The formation of deprotonated forms of tetra(t-butyl)phthalocyanine ((H₂ tButPc) 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.     

Synthesis of meso-mono-phenylporphyrins with active groups in the benzene rings

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.     

Oblique Phonons in Raman Scattering and IR Reflection of TeO2 Crystal

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.     

Infrared lattice vibrations of PbGa2S4

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 B_1u modes and 11 B_2u 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.     

Kinetics of the formation and dissociation of complexes of cobalt(II) with <Emphasis Type="Italic">meso</Emphasis>-Phenylocta(methyl)porphyrin derivatives in organic solvents

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.     

Wide-line 1H NMR and DSC study of mesomorphic transformations of p-(alkoxybenzylidene)-p′-toluidines

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.