CONTROL OF THE SOLID-STATE PHOTODIMERIZATION OF SOME DERIVATIVES AND ANALOGS OF TRANS-CINNAMIC ACID BY ETHYLENEDIAMINE

Some of double salts derived from ethylenediamine (en) and a variety of trans-cinnamic acids and their analogs underwent photodimerization in the solid state, giving predominantly beta-truxinic dimers. X-Ray studies demonstrate that (a) the conformation of en is gauche for the highly photoreactive double salts (o-1b . en and m-1e . en), whereas it is anti for less photoreactive o-1a . en or photoinert 1d . en and (b) for highly reactive o-1b . en and m-1e . en, the monomer acid molecules are arranged in an overlap configuration and a reactive monomer pair is hydrogen-bonded to the same en molecule.