Ir spectroscopy of 2,3-polymethylene-3,4-dihydroquinazolines and their complexes

We have investigated the IR spectra in the region of stretching vibration of N⁺–H and OH groups of the hydrochlorides of 2,3-trimethylene-3,4-dihydroquinazoline (deoxypeganine, DOP), 2,3-tetramethylene-3,4-dihydroquinazoline (tetrazoline), and 2,3-pentamethylene-3,4-dihydroquinazoline (pentazoline) and peganol and peganine and the corresponding complexes with ZnCl₂, CoCl₂, and MnCl₂. The appearance of two additional absorption bands in the 3100–3300 cm^–1 region in the complexes investigated as compared with the corresponding hydrochlorides witnesses the formation of interionic hydrogen bonds between the quinazoline cation and the (MeCl₄)^2– anion.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Republic of Uzbekistan, Tashkent, fax (3712) 40 64 75. Translated from Khimiya Prirodnykh Soedinenii, No. 6., pp. 854–857, November–December, 1997.     

Creatinine and creatininium cation in DMSO-d6 solution. Structure and restricted internal rotation of NH2 group

Investigation of 15N NMR spectra of isotopically enriched creatinine has unequivocally shown that in DMSO-d6 solution it exists as amino tautomer (2-amino-1-methylimidazoline-4-one), which in the presence of acid is protonated at N-3. Free energies of activation of the amino group rotation in creatinine and its cation have been determined to be 56 kJ/mol and 60 kJ/mol, respectively, at 298 K, by performing the simultaneous analysis of the lineshapes of -NH2 proton signals in the whole set of 1H NMR spectra recorded at various temperatures and magnetic fields. These results have been theoretically reproduced by the calculations of molecular structures and energies of creatinine and creatininium cation in their ground states and transition states of the amino group rotation, using DFT (B3LYP) method, involving the influence of the solvent.     

Growth and structure of ZnSnAs2 crystals

High-quality ZnSnAs₂ (I) single crystals have been grown. The unit cell parameters of compound I have been refined (a = b = 5.8360(1), c = 11.686(2) Å), and its crystal structure has been determined.     

Temperature effect on the viscoelastic properties of solutions of cylindrical mixed micelles of zwitterionic and anionic surfactants

The viscoelastic properties of semidilute mixed aqueous solutions of oleyl amidopropylbetaine and sodium dodecylbenzene sulfonate are studied in the temperature range of 20–40°C. It is shown that, at 20°C, the solution viscosity can be as high as 390 (Pa s), which is related to the formation of a network of entanglements of long cylindrical micelles of surfactants. It is revealed that, upon heating, the viscosity and relaxation time of the system decrease, while the contour length of cylindrical micelles decreases consider-ably. It is shown that this susceptibility of viscoelastic surfactant solutions to temperature is due to the low energy of break, which is much lower than the energy of covalent bonds.     

Canonical and Boundary Representations on the Lobachevsky Plane

Canonical representations on Hermitian symmetric spaces G/K were introduced by Vershik, Gelfand and Graev and Berezin. They are unitary. We study canonical representations in a wider sense. In this paper we restrict ourselves to a crucial example – the Lobachevsky plane: G=SU(1,1), K=U(1). Canonical representations are labelled by the complex parameter (Vershik–Gelfand–Graev's representations correspond to –3/2<<0). We decompose the canonical representations into irreducible components. The decomposition includes boundary representations generated by the canonical representations. So we study these boundary representations themselves. The decomposition of boundary representations is closely connected with the meromorphic structure of Poisson and Fourier transforms associated with canonical representations. In particular, second-order poles give second-order Jordan blocks. Finally, we give a full decomposition of the Berezin transform using generalized powers (Pochhammer symbols) instead of usual powers of .     

A quantum-chemical investigation of deoxypeganine and its salts II. The photochemical oxidation of deoxypeganine hydrochloride

The stability of deoxypeganine hydrochloride under the action of light has been established. The kinetics of the oxidation of deoxypeganine hydrochloride in aqueous solution in the presence of deoxyvasicinone hydrochloride have been studied. The structures and electronic conformations of hypothetical models of the salt DOP HCl in the ground and excited states have been considered by the MO LCAO method in the AM1 approximation. The difference in the resistance of the molecules of the base deoxypeganine and its hydrochloride to photochemical oxidation is discussed on the basis of the results of experiments and calculations.     

Dehydrohalogenation of substituted diethyl halocyclopropane-1,1-dicarboxylates

The synthesis and dehydrohalogenation of diethyl halocyclopropane-1,1-dicarboxylates prepared from diethyl ethylidene- and benzylidenemalonates are described.__________Translated from Zhurnal Organicheskoi Khimii, Vol. 40, No. 12, 2004, pp. 1811–1814.Original Russian Text Copyright © 2004 by Boitsov, Kostikov, Molchanov, Stepakov, Baird.     

Reaction of dichloro- and dibromocarbenes with 2-(vinyloxy)-1,3-butadiene

Conclusions A disubstituted multiple bond has the greatest activity in the reaction of 2-(vinyloxy)-1,3-butadiene with dichloro- and dibromocarbenes. The vinyloxy group stabilizes the transition state less effectively than the alkyl or aryl substituent.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1286–1290, June, 1979.     

Electron Emission Properties of Self-Assembling Nanodiamond‒Polymer Nanocomposite Coatings

Crystallography Reports - The formation of thin-film coatings from detonation nanodiamond (DND) suspensions on atomically ordered conducting Ni–W substrates by self-assembly in an evaporating...