Formation of a Topochemically Photoreactive Mixed Crystal by Grinding and Its Mechanistic Interpretation

Abstract

A mixed crystal of ethyl and propyl α-cyano-4-[2-(4-pyridyl)ethenyl]cinnamate was formed in the solid state by simple grinding. The mixed crystal formation was ascertained by the change in the X-ray diffraction pattern upon grinding and by 1H NMR and HPLC analyses of the photoproducts. According to several attempts, it was concluded that a mechanical treatment was necessary for the formation of the mixed crystal phase. The kinetic data concerning the analysis of the topochemical photoproducts revealed that the following growth of the mixed crystal phase was triggered by each of the mixed crystal nuclei and that the growth of the mixed crystal phase was accelerated by either thermal annealing or exposure in humidity. During the early stage of mixed crystal growth, the growth rate was nearly proportional to the surface area of the nuclei of the mixed crystal.

A [2+2] cross-photodimerisation of photostable olefins via a three-component cocrystal solid solution

“…[2+2] Cross-photodimerisation reactions (CPRs) in the solid state are a challenging task, with a relatively small number having been reported. [1][2][3][4][5][6][7][8][9][10][11] The main approach to conduct a solid-state CPR has involved the use of solid solutions [1][2][3][4][5][6][7][8] wherein two structurally-related molecules react in a lattice that is isostructural with at least one of the pure olefins. Success of the approach has, thus, relied on at least one of the olefins crystallising to be reactive as a pure solid.…”

Solid-State Photoreactions in Two-Component Crystals

“…14 It appears, however, that interpretations of the above-mentioned spectral and physical data for a simple mechanical mixture, a mixed crystal and a weak molecular complex are not always straightforward. [15][16][17] Hence, the characterization may potentially lead to controversy. Furthermore, only a few institutions for organic chemistry are well equipped with these facilities.…”

Solvent‐Free Photosynthesis of Cyclobutanes: Photodimerization of Crystalline Olefins

“…,Scheme 36 198,[201][202][203] , Scheme 37204 -207 , Scheme 38207 -209 , Scheme 39204 -207, 210 -216 , Scheme 4037, 217 -223 , Scheme 41218, 219, 224 -233 and Scheme 42225,230,232,233 . No examples of two-component crystal dimerizations and polymerizations are included.…”