Unsymmetrical Photodimerization of a 9-Aminomethylanthracene in the Crystalline Salt

By the salt formation with particular nonaromatic dicarboxylic acids, rapid and selective photodimerization of
9-(N,N-dimethylaminomethyl)anthracene (1) was accomplished in the solid state. For instance, the salt with
trans,trans-muconic acid or acetylenedicarboxylic acid was
led quantitatively to the 9,10:4‘,1‘ photodimer usy-ht-2, the
first example of the unsymmetrical [4+4] photodimerization
of anthracene in the solid state. The reactions were rationalized by the relevant C···C distances between the reacting
carbons.