Molecular Organization of 2,1,3-Benzothiadiazoles in the Solid State

Derivatives of 2,1,3-benzothiadiazole
(1) are widely
used in many areas of science and are particularly valuable as components
of active layers in various thin-film optoelectronic devices. Even
more effective benzothiadiazoles are likely to result if a deeper
understanding of their preferred patterns of molecular association
can be acquired. To provide new insight, we have analyzed the structures
of compounds in which multiple benzothiadiazole units are attached
to well-defined planar and nonplanar molecular cores. Our results
show that molecular organization can be controlled in complex structures
by using directional S···N bonding of benzothiadiazole
units and other characteristic interactions. Moreover, the observed
structures are distinctly different from those of analogous arenes.
Replacing benzene rings in arenes by thiadiazoles thereby provides
a strategy for making new compounds with extended systems of π-conjugation
and unique patterns of molecular organization, including the ability
to co-crystallize with the fullerenes C60 and C70.