H. Koshima et al., PHOTOCONDENSATION IN POLYCRYSTALLINE MIXTURES OF ARYLACETIC ACIDS AND1,2,4,5-TETRACYANOBENZENE, Journal of photochemistry and photobiology. A, Chemistry, 87(3), 1995, pp. 219-223
Irradiation of simple polycrystalline mixtures (1:1 molar ratios) of p
henylacetic acids, such as 4-tolylacetic acid and 4-methoxyphenylaceti
c acid, and 1,2,4,5-tetracyanobenzene caused decarboxylations followed
by dehydrocyanating condensation to give monobenzyltricyanobenzenes a
nd dibenzyldicyanobenzenes. In the case of a polycrystalline mixture o
f 9-fluorenecarboxylic acid and tetracyanobenzene, the decarboxylation
product 9-fluorene was obtained as the main product. The reactions pr
oceed at the interface of the component crystallites. The product sele
ctivities were different from those of the solution reactions.