Research on isoalloxazine derivatives

A convenient route to 9-(-aminoethyl)isoalloxazines is offered, based on monoacetylethylenediamine. 6-Chloro-7-methyl-9-(-aminoethyl)-isoalloxazine is used to synthesize some acyl derivatives and azomethines, among them some with the bis(-chloroethyl)amino group, for biological testing.For Part II see [10].     

Time-resolved and steady state spectroscopy of polydisperse colloidal silver nanoparticle samples

A signal due to coherently excited vibrational motion has been observed in polydisperse silver nanoparticle samples. The particles were synthesized via a wet chemistry seed mediated method, which yields different particle shapes, including spheres, rods, and irregular triangular-shaped particles. The measured vibrational periods were compared to the results from continuum mechanics calculations. This analysis shows that the observed signal arises from the triangular-shaped particles, rather than the rods or spheres. The period of vibration increases as the dimensions of the triangular-shaped particles increase; specifically, we find that the period is given by 2h/c(l), where h is the bisector of the triangle and c(l) is the longitudinal speed of sound in silver.     

Reaction of 3H-perfluoroalk-2-enes with ammonia

3H-Perfluoroalk-2-enes react with aqueous ammonia to form polyfluorinated iminoenamines, from which hexafluoroacetylacetone and its analogs were synthesized.     

Comparative Study of Reactivity of Cellulose,Chitosan, and Chitin-Glucan Complex in Sulfoethylation

Sulfoethylation of the chitin-glucan complex, isolated from mycelium of the mold fungus Aspergillus niger, by substitution with sodium -chloroethylsulfonate or addition of sodium vinylsulfonate is examined. A comparative study is made of the reactivity of the chitin-glucan complex, chitosan, and cellulose in the both reactions. The sorption characteristics of the sulfoethylated products with respect to Cu(II) and Cr(III) are determined.     

Additive coloration of crystals of calcium and cadmium fluorides

The particular features of additive coloration—formation of color centers as a result of annealing in a reducing atmosphere—have been considered for two crystals with fluorite structure, calcium and cadmium fluorides. The significant differences in the processes of coloration of these crystals are related to both the chemical reactions on their surface and the interaction (or absence of such) between the two components diffusing into the crystal bulk: anion vacancies and electrons.     

Fluorescence of albumin solutions containing Pb2+ and Na+ ions

Solutions of bovine serum albumin with metal ions Pb²⁺ and Na⁺ were studied by fluorescence analysis in the visible and UV ranges in relation to such parameters of the medium as the concentration of macromolecules, the pH, and the ionic strength of the solution. The formation of nanoparticles, protein clusters, in aqueous solutions of albumin containing ions of such a heavy metal as lead was revealed by fluorescence polarization analysis. This investigation is of practical value for the solution of ecological and medical problems.     

Composite Fibers Based on Chitin

Composite fibers containing chitin and cellulose ethers (methyl, hydroxyethyl, and hydroxypropyl cellulose) and also chitin and polyvinylpyrrolidone were prepared. The effect of the ratio of system components and also the molecular weight of polyvinylpyrrolidone on the deformation-strength characteristics of the composite fibers and their supramolecular organization was studied.     

Electrochemical synthesis of perfluoropolyethers by the Kolbe method

Electrochemical dimerization of hexafluoropropylene oxide dimer and trimer acids on SU-2000 glassy carbon, bulk platinum, and SU-2000 electrodes modified with platinum-group metals in acetonitrile in the presence of water was studied at various concentrations of the starting substance and different degrees of neutralization of the starting acid. Also, the possibility was examined of obtaining some perfluoropolyethers in a single process by cross-condensation of several starting perfluorocarboxylic acids, followed by separation of the products by physicochemical methods.