A. V. Yakimanskii

Second-order nonlinear optical susceptibility in chalcone-group crystalline molecular compounds

A study is reported of the second-order nonlinear optical susceptibility in polycrystalline molecular materials of the chalcone group made by second-harmonic generation at a wavelength of 1.06 µm. Some of the compounds studied exhibit a high nonlinear activity and are transparent in the blue region of the spectrum. The measured macroscopic nonlinear polarizability χ2 was compared with the calculated values of β, the second-order molecular polarizability tensor. The high nonlinear optical polarizability observed in some chalcone compounds is shown to be related to crystal symmetry type.

Synthesis and electrooptical properties of triphenylamine- and oxadiazole-containing polymers

Soluble aromatic polyimides and copolyimides are synthesized on the basis of 4,4′-diaminotriphenylamine and oxadiazole-containing diamines. Poly(ester oxadiazoles) are prepared from acid dichlorides or oxadiazole-containing acid dihydrazides. The optical, electrochemical, and thermal properties of the polymers are investigated. It is shown that oxadiazole-containing polyimides and poly(ester oxadiazoles) are able to transfer electrons, while triphenylamine-containing polyimides and copolyimides can transfer holes and electrons.

Electrochemical synthesis of cu-containing polyheteroarylenes and study of their catalytic properties

Method of electrochemical synthesis of new Cu-containing polyheteroarylenes that have biquinolyl units in their main chain is developed on the base of the soluble anode technique. The study of electrochemical properties of thus obtained Cu-containing polymer and the corresponding monomer complex revealed existence of two types of coordination environment: (1) copper Cu(I) in the tetrahedral surrounding of two biquinolyl ligands and (2) copper Cu(I) bound with only one biquinolyl fragment. The complexes with one biquinolyl polymer ligand showed high activity as catalysts for O2 reduction in the presence of hydroquinone that is converted to quinone in the course of the reaction.

Molecular mobility in comb-shaped copoly(methacrylates) with fluoromethylene and chromophore-containing side chains

The molecular mobility of copoly(methacrylates) with chromophore-containing side groups of various structures has been studied by the dielectric method. The region of relaxation of dipole polarization related to the segmental mobility (α process) has been discovered. At temperatures that are ∼30°C higher than those corresponding to the α process, the relaxation transition reflecting the reorientation of chromophore-containing side groups (δ process) takes place. It is suggested that the occurrence of the δ process is a general phenomenon for such systems. This effect allows one to determine the temperature at which the polarization of polymer films under application of corona discharge should be carried out so that a high level of nonlinear optical properties associated with the macroscopic noncentrosymmetrical orientation of chromophores may be achieved.

Synthesis and properties of glycidyl methacrylate copolymers with side chromophore groups

A number of styrylquinoline chromophores with carboxyl groups have been prepared through the interaction of 2-methylcinchonic acid with aromatic aldehydes of various chemical structures. The copolymer of glycidyl methacrylate and methyl methacrylate carrying side epoxide groups has been synthesized, and the chemical modification of the copolymer with the above chromophores has been performed. The thermal, spectral, and nonlinear optical properties of the chromophores and modified polymers have been studied.

Optical and photosensitive properties of comb-shaped polyamide-imides

A new method for modifying polymers with side carboxyl groups by glycidyl ethers of hydroxyl-containing azobenzene dyes has been developed. The spectral, thermomechanical, and photosensitive properties of dye-modified polyamide-imides have been studied as a function of the dye content in a polymer. The films of polymers under study were shown to be almost transparent at wavelengths above 500 nm. The mobility of side chromophore groups is rather high, which makes these polymers promising for nonlinear optical applications. The polymers are characterized by a photosensitivity of 103–104 cm2 J−1, which can be significantly increased by doping with diphenylamide molecules, which transport charge carriers.

Synthesis of Silver Glyconanoparticles Based on 3-Thiopropionylhydrazones of Mono- and Disaccharides

A method of synthesis of silver glyconanoparticles with average particle size 15–40 nm and low polydispersity index based on available 3-thiopropionylhydrazones of mono- and disaccharides has been elaborated. The prepared compounds have exhibited high antifungal, antibacterial, and antiviral activity and are promising for further comprehensive study.

Photosensitivity of polyimides and polyquinazolones based on aromatic and heteroaromatic diamines

Soluble polyimides containing triphenylamine residues as substituents at the imide nitrogen atom and polyquinazolones with diphenyl oxide, diphenylpropane, benzimidazole, benzoxazole, benzothiazole, oxadiazole, and triphenylamine moieties in the diamine component of the repeating unit have been synthesized. The spectroscopic study of polyquinazolones indicates their capability for donor-acceptor interactions. Emission bands of the polymers are of the exciplex nature. The photogeneration of current carriers in the polymers under study has been examined by the method of surface potential photoinduced decay. It has been shown that the intrinsic photosenitivity of polyquinazolones is nearly the same as (or somewhat higher than) that of the corresponding polyimides, but the former polymers are characterized by a less efficient spectral sensitization by dyes and donor-acceptor additives.

Synthesis and electrochemical properties of ruthenium(II) complexes with biquinoline-containing polyamic acids—Polybenzoxazinone prepolymers

New polyamic acids with biquinoline units in the backbone, which are prepolymers of polybenzoxazinones, as well as their metal-polymer complexes containing [Ru(bpy)2]2+, were prepared. The electronic structure of these polymers was studied with the use of cyclic voltammetry, electronic absorption spectroscopy, and quantum-chemical calculations, and the location sites of electronic changes upon electrochemical reduction and oxidation were determined.

Self-assembly of micro- and nanostructures during their two-stage spin-coating

Two-layer films were prepared by spin-coating the dispersions of polymer or silica nanoparticles onto the layer of polystyrene microspheres. It is shown that the lower layer formed by larger particles causes a structuring effect on the upper layer. This is a prospective technological method for preparing nanostructured substrates and films.