Electronic structure and properties of pteridines and N-alkylpteridinium salts

The electronic structure of pteridines and N-methylpteridinium cations was calculated in terms of the CNDO/2 approximation. The obtained data on the electron density distribution in the molecules of pteridines and also the energy characteristics of the pteridinium cations make it possible to predict the outcome of quaternization. The results from the calculations are compared with the experimental data. It is shown that the direction of nucleophilic attack in N-alkylpteridinium cations correlates with the total charge of the fragment of the covalently bonded atoms.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1118–1125, August, 1989.     

Mechanochemical effects in titanium nickelide-stainless steel bilayer samples

The products formed as a result of the mechanochemical reaction occurring in the course of the combined deformation of two samples, titanium nickelide and stainless steel, under the effect of impact loading are investigated.     

Comb-shaped homo- and copoly(arylene ether ketones) containing hydrophilic groups in side chains

Comb-shaped poly(arylene ether ketones) containing hydrophilic fragments in side chains are synthesized through the interaction of side reactive carboxyl groups of poly(arylene ether ketones) with methyl ethers of poly(ethylene glycol). Films based on these polymers possess tensile strengths up to 89 MPa and relative elongations at break up to 340%. Comb-shaped poly(arylene ether ketones) swell in water, and some of them show solubility in ethanol and methanol.     

Synthesis of N 3,N 5,4-triaryl-2,6-dimethyl-1,4-dihydropyridine-3,5-dicarboxamides

Russian Journal of Organic Chemistry -     

Electrical transport properties of poly(aniline-co-p-phenylenediamine) and its composites with incorporated silver particles

Statistical copolymers of aniline and p-phenylenediamine, poly(aniline-co-p-phenylenediamine)s, were synthesised by oxidative polymerisation using various oxidants, ammonium peroxydisulphate or silver nitrate. Depending on the choice of oxidant, copolymers or composites with silver particles were obtained. Different molar concentrations of p-phenylenediamine in the reaction mixture provided materials of different conductivities. The influence of both the copolymer composition and the presence of discrete silver particles on the electric and dielectric properties of the system was studied. The results showed a decrease in the conductivity of copolymers and their composites with the silver content compared with the content of standard polyaniline salt. The reduction in conductivity was described in terms of the decreased density of hopping centres due to defects in the copolymer structure. The dielectric relaxations observed were described in terms of their activation energies and were linked to the corresponding conduction mechanism.