Photolabile group, photosensitive

In general, group X in the prepolymer could be a number of possible photolabile groups. Benzoin alkylethers are usually superior to other photosensitizers studied for the photopolymerization of allylamines Therefore, prepolymers are prepared in which group X is derived from an unsaturated benzoin derivative of which several suitable structures are shown ... 

Evidence presented thus far for the putative role played by the photoliberated surfactants has been somewhat circumstantial. Conventional infrared and ultraviolet spectroscopy establish that the photolabile protecting group is photolyzed and the surfactant released under photolysis acid-base indicators, when added to the photosensitive coating, confirm the release of acid for the anionic surfactant derivatives. The surface sensitive spectroscopic techniques of ESCA (Electron Spectroscopy for Chemical Analysis) and RAIR (Reflection-Absorption Infrared) spectroscopy establish the involvement of the surfactant more unequivocally. 

The reagent (138), for photolabile carbonyl group protection, oxidized carbonyl compounds R COR (alcohols, ethers, and esters) under mild acidic or neutral conditions to the photosensitive acetals (139). The oxidation was presumably via hydride abstraction by the tritylium ion generated from (138) under acidic conditions. The primary and secondary alcohols showed unexpected similarities in reactivity, which had been rationalized by proposing slightly different mechanisms. High protection/de-protection efficiencies and remarkable dark stability of the acetals has been reported. ... 

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