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.     

Ionization in antiproton-hydrogen collisions

Employing the semiclassical approximation we calculate within the coupled-state formalism the ionization probability in antiproton-hydrogen (p+H) collisions. In particular we investigate the adiabatic ionization at the distance of closest approach in almost central collisions. Striking differences in the electron excitation probability compared with proton-hydrogen (p+H) collisions are predicted.     

Reaction of 5-chloroanthra[1,9-cd]-6-isoxazolone with oxygen-containing nucleophiles

Facile nucleophilic substitution of the chloride ion to give 5-alkoxy- or 5-aryloxy-anthra[1,9-cd]-6-isoxazolones occurs in the reaction of 5-chloroanthra[1,9-cd]-6-isoxazolone with alcohols and phenols. The possibility of conversion of the synthesized isoxazolones to 1-amino-4-alkoxyanthraquinones is demonstrated.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1329–1331, October, 1983.     

Über die Konzentrationsabhängigkeit der Viskosität bei organischen Hochpolymeren

Zusammenfassung Es wird eine Korrekturformel zur 8. Potenzformel von Philippoff-Heß vorgeschlagen, die auch die Fälle gut wiedergibt, wo die einfache 8. Potenzformel ebenso wie andere Viskositätsgleichungen bisher versagten. Im einzelnen wird die Gleichung geprüft an folgenden bisherigen Ausnahmen: Cellit in Eisessig (Philippoff-Heß), polymere-Hydroxydekansäuren in sym-Tetrachloräthan(Kraemer-von Natta), polymere Polystyrole in Benzol (Dane). In jedem Falle stellen diek-Werte gute Konstanten dar.Die charakteristische Viskositätskonstantek zeigt eine lineare Zunahme mit dem Molekulargewicht der Polymerhomologen.Die Temperaturabhängigkeit vonk unda wird geprüft.     

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^*).