Photoinduced structure transformations in dichromate-impregnated denatured collagen

X-ray structure analysis shows that irradiating gelatin films containing chromates causes a spiral-coil transition in the denatured collagen molecules. The concentration and type of the chromate have substantial effects, as do the film preparation conditions. The x-ray diffraction and ESR data indicate that chromium(V) compounds formed by photoreduction from chromium(VI) ones are mainly responsible for the conformation transition. In the absence of chromium compounds, light absorbed by the gelatin macromolecules results in macroradicals on account of the photolysis in the denatured protein chains. There is no phase transition.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 24, No, 2, pp. 247–251, March–April 1988.     

Condensation of aryl bromides with styrenes,catalyzed by nickel complexes in the presence of zinc

Conclusions Condensation of aryl bromides with styrenes in acetonitrile in the presence of nickel organometallic complex catalysts and metallic zinc occurs regio- and stereoselectively to give E-stilbenes.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 11, pp. 2508–2511, November, 1987.     

Spectroscopic Study of Reaction of Propargyl Bromide with Pyridine

Pyridine was reacted with propargyl bromide to obtain the dibromide [C₅H₅NCH = CHCH = CHCH = CHC₅H₅N]^{2 +} 2Br^-. The effect of the vinyl group on its UV spectrum is qualitatively interpreted using the results of nonempirical quantum-chemical calculations (basis HF/6-31G^*).     

NMR Study of Structural Changes in Humic Acids of Meadow Soddy Soils

Quantitative and qualitative changes in humic acids of meadow soddy soils, occurring under the action of various fertilizer systems, were studied by ¹³C and ³¹P NMR.     

Laboratory and Industrial Applications of Microwave Techniques

The use of microwave techniques in scientific research is reviewed. Also some semicommercial-scale microwave units are examined.