Abstract: 4,4′-[1,n-alkanediylbis[(E)-2-(4-oxyphenyl)ethenyl]]bispyridine [n=2(Ia), 3(Ib),4(Ic), 6(Id)] were synthesized by the nucleophilic substitution of (E)-4-[2-(4-hydroxyphenyl)ethenyl] pyridine with 1,n-dibromoalkane.The structures of Ia～Id were identified by elemental analysis, IR, UV and 1H NMR. The dilute solution of Ia～Id was irradiated alternatively by medium pressure mercury lamp and low pressure mercury lamp. The intramolecular photocycloaddition was observed and this reaction speeds up with the extension of the alkanediyl chain. It was also found that the photocycloaddition was increased in the presence of zinc cation because of its chelation with the nitrogen atom of the pyridine group. The fluorescence of these compounds is weak and the intermolecular excimer fluorescence is detected at higher concentration.

Key words: Bispyridine, Intramolecular photocycloaddition, Excimer, Fluorescence (FL)