Network polymers based on 3,3-bis-(4′-hydroxyphenyl)phthalide and [2.2]paracyclophane-4,16-dicarboxylic acid

A linear ester is synthesized on the basis of phenolphthalein and [2.2]paracyclophane-4,16-dicarboxylic acid dichloride. The formation of network polymers via the heat treatment of this ester in a wide temperature range is studied. The physical properties of these polymers are investigated. The computer-aided simulation of several physical parameters (including the glass-transition temperature and the dielectric constant) is performed for both the linear polymer and feasible network structures. There is a good correlation between the experimental results and the calculated data.     

Electrically conductive polyaniline—A molecular magnet with the possibility of chemically controlling the magnetic properties

Different forms of an electrically conductive polymer, an organic semiconductor, namely, polyaniline, have been synthesized and characterized. The magnetization curves of the obtained forms have been analyzed. It has been found that, in the oxidized form, the material exhibits a magnetic hysteresis at room temperature. For polyaniline without a special doping with magnetic additives, this result has been obtained for the first time. The possibility of controlling the magnetic properties of the material by means of chemical treatment at the post-polymerization stage has been demonstrated.     

Synthesis of 4,n-diaryl-2,7,7-trimethyl-5-oxo-1,4,5,6,7,8-hexahydro-3-quinolinecarboxamides

The reaction of dimedone, N-aryl-substituted acetoacetic acid amides, aryl aldehydes, and ammonium acetate gives 4,N-diaryl-2,7,7-trimethyl-5-oxo-1,4,5,6,7,8-hexahydro-3-quinoline carboxamides.     

Second-harmonic generation taking into account dispersion of nonlinear susceptibility

Second-harmonic generation in the field of an ultrashort pulse and the propagation of extremely short pulses in a medium with quadratic nonlinearity are analyzed. Second-harmonic generation is analyzed taking into account the effect of second-and third-order group velocity dispersion and dispersion of nonlinear susceptibility up to the second order. Corrections, whose order of smallness is determined by the parameter (ω_L t _p)^?1, where t _p is the pulse duration and ω_L is the carrier frequency of the pump wave, are obtained. For a large phase mismatch, two new solutions are found that describe the stationary evolution of solitary pump and second-harmonic waves in the regions of both anomalous and normal group velocity dispersions.     

Reaction of Vinylpyridines with Active Modifications of Elemental Phosphorus in KOH/DMSO

The phosphorylation of 2-vinyl- and 4-vinylpyridines by white phosphorus and active modifications of red phosphorus (obtained by thermal polymerization of white phosphorus in the presence of graphite or the action of ionizing radiation in benzene) in the KOH/DMSO superbase system at room temperature leads to the formation of tris[2-(2-pyridyl)ethyl]- and tris[2-(4-pyridyl)ethyl]phosphine oxides in 58-72% yield. These oxides are promising ligands for design of metal complex catalysts. These vinylpyridines react less efficiently with ordinary red phosphorus and the yield of the corresponding tris(2-pyridylethyl)phosphine oxides does not exceed 10%.     

Inelastic interaction of ultrashort pulses of polarized light with an ensemble of isolated quantum dots

A system of equations is formulated describing the evolution of a slowly varying envelope of an arbitrarily polarized ultrashort pulse of electromagnetic radiation in a medium with its resonant properties determined by an ensemble of isolated quantum dots. It is assumed that the concentration of quantum dots is small and that the whole system is equivalent to a gas of resonant four-level atoms. Particular solutions are found that correspond to the propagation of a stationary optical pulse. It is shown by numerical solution of the generalized truncated Maxwell-Bloch equations that steady-state propagation is possible only for circularly polarized light pulses, whereas the pulses of arbitrary polarization either decay and experience the dispersion-related broadening or are converted into circularly polarized solitary waves.     

Enhancement of the Local Electromagnetic Field over Planar “Particles” Formed on the Surface of a Polar Crystal

Small “particles” of an open surface were formed on a SiC polar crystal with openings in the opaque metal mask covering the sample. The dimensions of the holes were about surface phonon polariton wavelength. Such a sample was irradiated with an electromagnetic wave ( λ = 10.68μm) at a frequency close to the lattice resonance of SiC. A significant enhancement in the field amplitude of surface phonon polariton waves was detected over such “particles” compared to the amplitude over an infinite open surface of SiC. Such a phenomenon, observed by us in the IR band, is similar to plasmon resonance on small metal particles in the visible band, but the lateral resolution of the ASNOM used (no worse than 30 nm at 10 μm) makes the obtained field distribution more detailed. The maps of the local field amplitude and phase obtained on SiC surface with ASNOM are in a good quantitative agreement with simulations using the Green’s function.     

Electronic structure of active centers and kinetic stereocontrol in polymerization of butadiene under the influence of a catalytic system based on neodymium chloride

On the basis of quantum-chemical calculations of models of active centers, a suggested mechanism of kinetic stereocontrol of the microsctructure in polymerization of butadiene under the influence of the catalytic system NdCl₃ · 3TBP-HA1 (i-C₄H₉)₂ has been verified experimentally.Institute of Chemistry, Bashkirian Scientific Center, Urals Branch, Russian Academy of Sciences, Ufa. Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 27, No. 6, pp. 741–745, November–December, 1991. Original article submitted August 9, 1990.