Synthesis and Characterization of Novel Dipyridylbenzothiadiazole and Bisbenzothiadiazole Derivatives

Novel dipyridyl compounds containing a mono- and bisbenzothiadiazole unit were synthesized using
the Stille coupling reaction. Their pyridinium salts, viologen analogues, were also prepared by the
N-alkylation. The X-ray crystallographic analysis of the compounds containing a benzothiadiazole
ring revealed nonplanar molecular structures and unique crystal structures depending on the
nitrogen positions. The dipyridyl compounds are efficient fluorophores with high electron affinity.
The derivative afforded complexes with chloranilic acid and cyanuric acid composed of hydrogen
bonding networks. The methyl viologen analogues showed two-stage one-electron reduction waves.