Photodimerization of (E)-3-(2,6-Difluorophenyl)-1-(4-methoxyphenyl)prop-2-en-1-one in the Crystalline Solid State

(E)-3-(2,6-difluorophenyl)-1-(4-methoxyphenyl)prop-2-en-1-one (1) was synthesized and characterized by H-1 and C-13 NMR, mass spectrometry, and single-crystal X-ray diffraction. Photolysis (lambda(irr) = 300 nm) of chalcone 1 in the crystalline solid state resulted in the stereospecific formation of the syn-head-to-head photodimer (beta-truxinic).