Alkyl-substituted dipyrrylmethenes and their oxa- and thia-analogs: “structure—solvation properties” correlations

New data on the spectral properties and solution enthalpies of unsymmetrically substituted 2-(alkyl-2-pyrrolylmethylidene)methylpyrrolium bromides (or ,-dipyrrylmethene hydrobromides), their ,-, ,-isomers, as well as their oxa and thia analogs, that is, 2-(2-furylmethylidene)- and 2-(2-thienylmethylidene)-3,4,5-trimethyl-1H-pyrrolium bromides, in solutions of organic solvents of different nature are presented. A decrease in the number of substituents, as well as replacement of the heteroatom (N) in one five-membered ring of the dipyrrylmetnehe by oxygen or sulfur atoms cause a monotonic hypsochromic shift of absorption bands in the electronic absorption spectrum and weakening of the chromophore properties of the compounds. The chromophore properties of isomers are weakened from the ,- to ,- and ,-dipyrrylmethenes. Main trends in the influence of structural factors on the specific features of thermooxidative destruction of the above-mentioned compounds were analyzed.     

Study of acidity and coordination properties of 2,3,7,8,12,13,17,18-octabromo-5,10,15,20-tetraphenylporphyrin in the system of 1,8-diazabicyclo[5.4.0]undec-7-ene-acetonitrile

Spectrophotometric titration method was used to study the acidic properties of 2,3,7,8,12,13,17,18-octabromo-5,10,15,20-tetraphenylporphyrin in the presence of a deprotonated agent, 1,8-diazabicyclo[5.4.0] undec-7-ene, in acetonitrile. The spectral characteristics of the ionized forms and combined ionization constant for the first and second stages were revealed. The reaction of complex formation between the dianionic forms of 2,3,7,8,12,13,17,18-octabromo-5,10,15,20-tetraphenylporphyrin and zinc acetate was studied.     

Rheology of liquid crystalline phases of alkyloxybenzylidene toluidines

A unique viscometer of the CS rheometer viscometer class designed at the Kazan State University of Technology is used to measure viscosities of two p-n-alkyloxybenzylidene-p-toluidines in the entire temperature range of the liquid crystalline state and transition into an isotropic liquid. The measured shear stresses and flow rates are used to calculate shear rates and plot flow and viscosity curves. The liquid crystalline phase and isotropic liquid are demonstrated to possess Newtonian viscosity, whose viscous flow activation parameters are calculated in the temperature range under study. The results are discussed from the standpoint of intermolecular interactions and structural details of the liquid crystalline phase.     

IR spectra of SiO2 films deposited from the gas phase

Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 55, No. 2, pp. 207–211, August, 1991.     

Spectral studies of protonated and anionic forms of porphyrins with an asymmetric substitution system

Journal of Inclusion Phenomena and Macrocyclic Chemistry - The directed synthesis of asymmetrically substituted porphyrins—tetraphenylporphyrine derivatives containing amino acid residues as...     

Interference of resonance luminescence of exciton polaritons in CuGaS2 crystals

The nonmodulated and wavelength-modulated reflection spectra of CuGaS₂ crystals for the polarization EIIc of 10 K are studied. The states n = 1, 2 and 3 of the excitons Γ₄ (A-excitons) and n = 1, n = 2 of B- and C-excitons are found. The nonmodulated absorption spectra for the polarization E⊥c at 10 K have been studied. The states n = 1, 2 and 3 of Γ₅ excitons are found. The main parameters of the A (Γ₄, Γ₅) and B, C exciton series at the energies of the longitudinal and transverse excitons Γ₄ for the states n = 1 and n = 2, the effective masses of electrons and holes are determined. The photoluminescence peaks were observed at n = 3 and n = 4 of the excitons Γ₅ in the luminescence spectra excited by the line 4880 Å of Ar⁺ laser. In the luminescence spectra the interference is found.     

The superposition of one- and two-phonon absorption and radiation in TeO2 crystal

Raman scattering and IR reflectivity for actual configuration have been investigated. The contours of reflectivity spectra rave been calculated. Phonon parameters have been determined. The temperature dependence of Raman scatterung and IR reflectivity indicated absence of soft modes in optical oscillations. Two-phonon processes of light absorption and radiation have been investigated. In the one-phonon mode frequency range, a two-phonon radiation which is completely absorbed by the crystal itself has been observed.     

Synthesis of tetraphenylporphines with active groups in the phenyl rings 6. Synthesis of monosubstituted tetraphenylporphines by diazotization

Monoaminophenyltriphenylporphines are diazotized and then used to produce monohalosubstituted tetraphenylporphines. Isomeric mono(p-hydroxyphenylazo)phenyltriphenylporphines are synthesized by replacing the azo group of diazonium salts of monosubstituted porphines with phenol.See [1] for Communication 5.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1507–1509, November, 1990.     

Kinetics of the Dissociation of Cu2+ and Co2+ Complexes of Nitro Derivatives of 5,15-Diphenyl-3,7,13,17-tetramethyl-2,8,12,18-tetraethylporphyrin in Proton-Donor Media

Russian Journal of General Chemistry - Copper and cobalt complexes of nitro derivatives of planar and nonplanar derivatives of 5,15-diphenyl- 3,7,13,17-tetramethyl-2,8,12,18-tetraethylporphyrin are...     

Crystal and molecular structure of 4(3-acryloyloxy)octyloxy- and 4(3-acryloyloxy)hexyloxy-4′-cyanobiphenyls

The molecular and crystal structures of N≡C-C₆H₄-C₆H₄-O-(CH₂)₈-O-CO-CH=CH₂ (4(3-acryloyloxy)octyloxy-4′-cyanobiphenyl) (I) and N≡C-C₆H₄-C₆H₄-O-(CH₂)₆-O-CO-CH=CH₂ (4(3-acryloyloxy)hexyloxy-4′-cyanobiphenyl) (II) were determined by X-ray diffraction. The structures of I and II are stereotype. The space group of I and II is C2/c, Z = 8; lattice parameters I: a = 34.677(7)?, b = 9.452(2)?, c = 13.004(3) ?, β = 99.30(3)°; II: a = 30.858(6) ?, b = 9.504(2) ?, c = 13.082(2) ?, β = 92.78(3)°. The planar extended molecules I and II are packed in the unit cell to give clearly differentiated aliphatic and aromatic regions throughout the whole crystal. All intermolecular contacts are concentrated in the aromatic region. The molecular packing is very loose but the aromatic areas of I and II fully coincide. The only free parameter of the structure is the length of the aliphatic chain (CH₂)n (n = 8 and 6). According to DSC data, compound I possesses enantiotropic mesomorphism and II possesses monotropic mesomorphism.