Synthesis of 3-substituted tetrahydroindol-4-one

Chemistry of Heterocyclic Compounds - A series of functionalized 4,5,6,7-tetrahydroindol-4-one derivatives containing a residue derived from β-dicarbonyl compound at position 3 were prepared...     

Effect of matrix domination in PANI interpolymer complexes with polyamidosulfonic acids

Various polyaniline (PANI) interpolymer complexes with polyacids in the form of molecular solutions were synthesized by chemical oxidative polymerization of aniline in the presence of water-soluble poly-(2-acrylamido-2-methyl-1-propanesulfonic acid) (flexible backbone), poly-p,p′-(2,2′-disulfoacid)-diphenylene-terephthalamide (t-PASA, rigid backbone), and their mixtures in different ratios. The complexes were characterized by UV-Vis-near infrared spectroscopy in solutions; also, the films’ drop-casts from these solutions were investigated by cyclic voltammetry, spectroelectrochemical, direct current (DC) conductivity, and atomic force microscopy (AFM) measurements. It was shown that the nature of polyacid affects the shape of spectra and the dynamics of their changes. The character of spectral changes during the matrix synthesis of PANI in the presence of mixtures of the rigid-chain and flexible-chain matrixes and the study of spectral properties of the obtained PANI solutions demonstrates the existence of the rigid-matrix domination effect in the process of formation of PANI interpolymer complexes. Spectral properties of the obtained PANI complexes with the mixtures of flexible-chain and rigid-chain polyacids of different ratios (3:1, 1:1, 1:3, and 1:6) are very similar to those ones for the complex with rigid-chain t-PASA. At the same time, there is a correlation between the electrical conductivity and morphology of the films of PANI complexes and their composition, the conductivity passing through a minimum for the complexes with the polyacid mixtures (6:1, 3:1, and 1:1).     

Intramolecular S···O chalcogen bond in thioindirubin

Results of X-ray diffraction study and quantum-chemical calculations revealed that molecular conformation of thioindirubin molecule creates suitable conditions for formation of intramolecular C–H···O and S···O interactions. Analysis of molecular electrostatic potential (MEP) demonstrates existence of two areas of positive MEP (σ-holes) in the outermost part of the sulfur atom on the continuation of the lines of the C–S bonds. One of these σ-holes is oriented toward region of negative MEP around the oxygen atom of carbonyl group. Such situation corresponds to formation of σ-hole or chalcogen bond. Existence of both types of bonding interactions is confirmed by topological analysis of electron density distribution using “Atoms in Molecules” (AIM) theory. Energies of the C–H···O hydrogen bond and the S···O σ-hole bond derived from AIM and NBO theories are very close.     

Photo- and cathodoluminescence of the cetylpyridinium chloride: ZnO nanocomposites

The cathodoluminescence and photoluminescence (PL) spectra of ZnO nanoparticles (NPs) embedded into the cetylpyridinium chloride (CPCL) matrix were studied. The composites were obtained by drying an aqueous suspension of CPCL and ZnO NPs, with NaCl and with NaOH additives. We observed that only NaOH addition lead to a significant increase in the PL intensity which we attribute to the surface chemistry of the ZnO NPs. We propose that thin ZnOH₂ and Na₂ZnO₂ layers form on the surface of the NPs; these layers present an increased number of oxygen vacancies, which act as emitting centres.     

One-Pot Three-Component Synthesis of Polysubstituted Tetrahydroindoles

Chemistry of Heterocyclic Compounds - A series of novel fused pyrrole derivatives was synthesized by one-pot three-component reaction of β-enaminoketones, derived from cyclohexane-1,3-dione or...     

Interaction of 3‐(2‐Aminophenyl)‐6‐R1‐1,2,4‐triazin‐5‐ones with Acylating Reagents: An Efficient Method for Preparation of 6‐Substituted 3‐R1‐2H‐[1,2,4]triazino[2,3‐c]quinazolin‐2‐ones

The series of 6‐substituted 3‐R¹‐2H‐[1,2,4]triazino[2,3‐c]quinazolin‐2‐one was prepared via condensation of 3‐(2‐aminophenyl)‐6‐R¹‐1,2,4‐triazin‐5‐ones with acylating reagents. Particularities of ¹H NMR spectra have been also discussed based on the comparison of experimental and theoretical results for 3‐methyl‐6‐phenyl‐2H‐[1,2,4]triazino[2,3‐c]quinazolin‐2‐one and its 4,3‐isomer.     

Control of tissue mechanics upon the repetitive-pulse laser heating of cartilage

The viscoelastic properties of laser-irradiated cartilages are studied with optoacoustic methods upon the thermal excitation of mechanical oscillations by repetitive-pulse laser radiation. The effect of laser power, pulse duration, repetition rate, and irradiation time on the shape of the optoacoustic signal is analyzed. It is demonstrated that the optoacoustic response of the cartilage to the repetitive-pulse radiation of a fiber laser depends on the softening of the tissue upon the variation in its shape. Under repetitive-pulse laser irradiation, the optoacoustic response of the cartilage depends on the mechanical characteristics of the biotissue (elastic modulus, hydraulic permeability, and thickness). A simple model that makes it possible to estimate the contribution of the viscoelastic properties to the formation of the optoacoustic response at various laser repetition rates is proposed.     

The specific effect of graphene additives in polyaniline-based nanocomposite layers on performance characteristics of electroluminescent and photovoltaic devices

A comparative study of the effect of graphene admixture to polyaniline hole-injection layers of polymer light emitting diodes (PLEDs) and anode buffer layers of organic solar cells (OSCs) has been performed. The layers have been made from the complex of polyaniline with poly-2-acrylamido-2-methyl-1propanesulfonic acid with (or without) addition of 1 wt % graphene prepared by the mechanochemical method. It has been shown that the effects of the graphene addition into the auxiliary PLED and OSC layers are opposite: performance characteristics (current and light efficiency) of the former deteriorate and those of the latter are improved (in particular, the powerconversion efficiency increases by a factor of 1.4). The reasons considered to be behind the opposite effects are a significant difference in the currents flowing through the PLED and OSC, a more developed interface between the OSC anode buffer layer and photolayer, and channeling the longitudinal conductivity at the interface between graphene nanoparticles and polyaniline.