Size Matters: [2+2] Photoreactivity In Macro- and Microcrystalline Salts of 4-Aminocinnamic Acid

作者：d'Agostino Simone^*; Boanini Elisa; Braga Dario; Grepioni Fabrizia^*

来源：Crystal Growth & Design, 2018, 18(4): 2510-2517.

DOI：10.1021/acs.cgd.8b00109

The solid-state photoreactivity of 4-aminocinnamic acid (1) and molecular salts [1H]ClO4 and [1H]HSO4 has been investigated, and structural changes have been monitored by X-ray diffraction techniques and FTIR spectroscopy. While the parent compound 1 and its perchlorate salt [1H]ClO4 are photoinert, irradiation of [1H]HSO4 single crystals results in partial single-crystal to single-crystal (SCSC) [2 + 2] photodimerization, with formation of a {[1H]HSO4}(0.36)center dot 1[1(2)H(2)][HSO4](2)}(0.64) solid solution. If crystalline powders of [1H]HSO4 are irradiated, however, the formation of a monomer/dimer solid solution is followed by "extrusion" and recrystallization of both the phodimerization product [1(2)H(2)]HSO4 and unreacted [1H]HSO4 as nonisomorphous crystal phases. The outcome of the UV irradiation of [1H]HSO4, therefore, is influenced by the crystal size of the reacting monomer and changes dramatically if the irradiated sample is in the form of single macrocrystals or microcrystalline powder.

• 出版日期2018-4