ABSTRACT
Polyalkynes have been studied in two categories with great efforts: polymerization and photobiological effects. The photochemistry of simple acetylenes, especially monoalkynes, is, however, well established and it has certain advantages of its own, especially in synthetic applications. Radical-stabilizing groups such as the tert-butyldimethylsilyl group on terminal carbons of conjugated hexatriynes control the photoaddition reactions of the compounds. The excited state chemistry of aryldisilanes has been extensively studied because unsaturated compounds show interesting photophysical and photochemical properties. In the photohydration reaction, a hydrated proton attacks the singlet excited state of the acetylene directly. Therefore shearing is possible, and consequently ortho- or meta-substituted diphenyldiacetylenes with polar substituents exhibit solid-state reactivity. Simple acetylenes are known to undergo various photoreactions such as intermolecular and intramolecular addition reactions, cycloaddition reactions, and rearrangement reactions. Investigation of the photohydration of nitro substituted aryl diacetylenes is therefore warranted.
