Crystal structure, Hirshfeld surface analysis and photophysical properties of disubstituted 4,4′-(benzo[c][1,2,5]thiadiazole-4,7-diyl)dianiline

• Published in: Journal of molecular structure 2024-10, Vol.1314, p.138637, Article 138637
• Main Authors: Wałęsa-Chorab, Monika, Ekti, Sultan Funda, Simard, Michel, Skene, W.G.
• Format: Article
• Language: English
• Subjects: Benzothiadiazole; Crystal structure; Diamine; Hirshfeld surface analysis; Solvatochromism
• ISSN: 0022-2860; 1872-8014
• DOI: 10.1016/j.molstruc.2024.138637

•Crystal structure of 4,4′-(benzo[c][1,2,5]thiadiazole-4,7-diyl)dianiline is reported.•The emission color of the dye was highly dependent on the solvent polarity.•The dye is electrofluorochromic with photoemission modulation with a potential.•The dye is electrochromic changing yellow to blue with a potential. Two independent molecules of the crystal structure of the title compound C18H14N4S were found to occupy the asymmetric unit of the space group. The flanking 4-anilines were not coplanar with the central benzothiadiazole. In the crystal, two unique types of hydrogen bonds were found: i) one set between two NH2 of two molecules in the asymmetric unit and ii) another set between hydrogen atoms of the second aniline NH2 and the nitrogen atom of benzothiadiazole. The two-dimensional fingerprint plots along with the Hirshfeld surface confirmed the most important contributions for the crystal packing were C···H, H···H and N···H interactions. The compound was also solvatochromic with both its emission wavelength and quantum yield contingent on the solvent polarity. The fluorophore had a reversible oxidation. This was used to induce both a reversible color change from yellow to blue and emission off/on with an applied potential. [Display omitted]