Solid-State Photoreaction in Two-Component Molecular Crystals of Thienylacetic Acids and Aza Aromatic Compounds

A series of two-component molecular crystals of 2-thienylacetic acid (1) or bis(2-thienyl)acetic acid (2) with aza aromatic compounds such as acridine (a) and phenanthridine (b) were prepared by crystallization from the solutions of both components. Irradiation of the crystals caused photodecarboxylation and radical intermediates which give decarboxylated and condensation products. The relationship between the crystal structures and the reaction paths are discussed.