Photosensitive triggering

Functional expression Forms a photosensitive pigment capable of triggering a phototransduction cascade Forms a photosensitive pigment that is incapable of triggering a phototransduction cascade Unknown... 

R. Taylor. In early experiments we uv irradiated C60 in hexane, but the amount of decomposition was dependent upon the particular batch of C60. Some decomposed completely within 4 h others showed little decomposition after 24 h. Therefore we keep C60 in the dark. Others have reported that the decomposition of C60 may be triggered by an impurity. Indeed deliberate initiation of decomposition has been reported. We have tried halogenation in the light and obtained a product which is different from that isolated under conventional conditions. C70 is also photosensitive it decomposes faster in hexane than in benzene. 

Photoswitchable enzymes could have an important role in controlling biochemical transformations in bioreactors. Various biotechnological processes generate an inhibitor, or alter the environmental conditions (pH, for example) of the reaction medium. Photochemical activation of enzymes that adjust environmental conditions or deplete the inhibitor to a low concentration may maintain the bioreactor at optimal performance. More specifically, integration of the photoswitchable biocataly-tic matrix with a sensory electrode might yield a feedback mechanism in which the sensor element triggers the light-induced activation/deactivation of the photosensitive biocatalyst. 

The reaction of diethyl zinc with water produces zinc oxide, and then zinc carbonate, as the alkaline reserve. These chemicals have antiseptic properties which may also prevent the growth of mold in paper. They may also improve the brightness of treated papers. However, it is also known that zine oxide is a photosensitizer (56) which may trigger photo-oxidation of treated papers to initiate a chemical chain reaction that will lead eventually to the formation of acidic products (57). Moreover, the interaction of zinc oxide and zinc carbonate with copper, iron and cobalt present in the paper and their subsequent effects on paper stability have not been studied. 

Juan C, Stefflova K, Niedre K, et al. Protease-triggered photosensitizing beacon based on singlet oxygen quenching and activation. J Am Chem Soc 2004 126 11450-1. 

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