Photodimerization and Photosalient Effects of 4-Styrylpyridine Cocrystals Using Aromatic Poly(carboxylic acid)s as Hydrogen Bonding Templates
Sotaro Kusumoto, Kei Sato, Kenta Rakumitsu, Yang Kim, Yoshihiro Koide
Abstract
In molecular crystals, observing the modulation in photoactuation properties provides insight into the dimerization of olefins, resulting from the [2 + 2] photocycloaddition reaction. Photodimerization and photosalient effects were examined in the cocrystals of 4-styrylpyridine (4-spy) employing aromatic dicarboxylic acids as hydrogen bonding templates, namely, the crystals with phthalic acid ( 1 ), isophthalic acid ( 2 ), and terephthalic acid ( 3 ). The observed effects were most notable in 3 for the former and in 1 and 3 for the latter. The efficiency of dimerization varied depending on the distance between adjacent C═C in 4-spy molecules and the parallel-to-cross arrangement ratio as well as the protonation/deprotonation ratio of the pyridine moieties, as determined by single crystal structural analyses.