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

Abstract

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 C and C.

Chalcogen Bonding “2S–2N Squares” versus Competing Interactions: Exploring the Recognition Properties of Sulfur

“…1,2,5‐Thiadiazoles present interesting systems, although the nature of their S ⋅⋅⋅ N interactions and the involved structural boundaries remain largely unexplored. Most knowledge has been derived from computational analysis .…”

“…For instance, it is now recognized that factors such as the hybridizations tate of sulfurc an alter its interactions. [12, 15-17, 19, 37, 38, 45, 46] 1,2,5-Thiadiazoles present interesting systems, [47,48] although the nature of their S···Ninteractions and the involved structural boundaries remain largely unexplored. Most knowledge has been derivedfrom computational analysis.…”

Thiadiazolo‐Azaacenes

“…13 (m, 62 H). The substance was not soluble enough for 13 CNMR analysis. IR (neat): n (cm À1 ) = 2924, 2852, 1460, 1343, 1118, 1080, 1000: m/z calcd for C 58 H 67 N 12 S 4 Si 2 :1 115.4028 [M+ +H] + ,f ound:1 115.4028, correct isotope distribution.…”

“…1 HNMR (500 MHz, CDCl 3 ) d = 2.08 (m, 6H), 1.65 (m, 6H), 1.36 (m, 18 H), 1.23 (m, 6H), 1.13 (t, J = 7.2 Hz, 18 H). 13 CNMR (126 MHz, CDCl 3 ) d = 154. 3,150.9,142.8,141.5,125.2,116.4,100.8,25.6,19.3,14.8,14.1.…”

“…The experimental and calculated CÀNb ond lengths fort he peripheral thiadiazole moieties are 0.03 shorter than for the thiadiazole annulated along the long axis, emphasizing their electronic decoupling from the acene backbone. Of interest is that only the "western", single benzothiadiazole participates in S-N-interactions, [13] with interatomd istances of 3.35 .C ompound 7 forms as taircase motif, whereby each ladderisseparated by one molecule of dichloromethane from its neighbor,f orming ap erforated pseudo-brickwall ( Figure 5). The fairly low interplanar distance of only 3.25 stresses the strong p-p-interactions of the rigid framework.…”