Effects of Donor and Acceptor Units Attached with Benzoselenadiazole: Optoelectronic and Self-Assembling Patterns

Here, we report the effects of electron
donor and acceptor units
attached with benzoselenadiazole for the change in optoelectronic
and packing patterns in solid states. We have synthesized 4-methoxybenzene,
naphthalene, and 4-nitrobenzene capped benzoselenadiazoles (compounds 1–3 respectively) and studied their photophysical
as well as electrochemical properties. All three molecules show two
absorption bands (π–π transition band and CT-band).
Three molecules (1–3) show orange,
yellow-green, and green colors in dichloromethane solutions upon irradiation
of UV light at 365 nm. Benzoselenadiazole-based compounds 1–2 form head to head dimers via Se···N
interactions in the solid states. Compounds 1 and 2 show interlock type packing via Se···N interaction
in their solid state structures. Se···π interaction
takes a major role to form interlocked sheet type structures in crystal
packing of compound 1, whereas Se···N,
N···N, and CH···π interactions
help to form a supramolecular sheet type of structure in the crystal
packing of compound 2. Band gaps of these compounds were
tuned by changing the electron donating to electron withdrawing units
attached with a benzoselenadiazole core.