Intra- and intermolecular excited state proton transfer in phenylbenzothiazole amides: excitation-controlled dual emission and a crystallization-based scratch sensor

Intra- and intermolecular excited state proton transfer in phenylbenzothiazole amides: excitation-controlled dual emission and a crystallization-based scratch sensor Full article

Journal

Journal of Materials Chemistry C
ISSN: 2050-7526 , E-ISSN: 2050-7534

Output data

Year: 2026, Volume: 14, Number: 37, Pages: 17567–17580 Pages count : DOI: 10.1039/d6tc01887d

Authors

Olennikov Vyacheslav E. ^1,2 , Kolybalov Dmitry S. ^2,3 , Pylova Ekaterina K. ¹ , Ryadun Alexey A. ¹ , Konchenko Sergey N. ¹ , Sukhikh Taisiya S. ¹

Affiliations

1	Nikolaev Institute of Inorganic Chemistry, Siberian Branch, Russian Academy of Sciences, Novosibirsk 630090, Russia
2	Department of Natural Sciences, National Research University—Novosibirsk State University, Novosibirsk 630090, Russia
3	Department of Synchrotron Research, SRF ‘SKIF’, Novosibirskaya oblast 630559, Russia

Funding (2)

1	Russian Science Foundation
2

How do molecular conformation, hydrogen bonding (intra- vs. intermolecular), and aggregation state (crystalline, colloid, solution) control the excitation-dependent ESPT behaviour? To answer this, we synthesized phenylbenzothiazole amides (A2–A4, B2–B4) that display dual-band excitation-dependent emission. To quantify this behaviour, we introduce simple and universal descriptor ECR (Excitation Contrast Ratio). In crystalline α‑A2, β‑A2, and B2, ECR reflects decrease of the ESPT-band contribution with increasing excitation wavelength – a behaviour expected for systems with a double-well potential energy surface featuring an energy barrier. In contrast, B2 in dilute solution and crystalline A3–B3 exhibit the opposite behaviour: the tautomer emission becomes more prominent at longer excitation wavelengths. Excitation spectra suggest the presense of coexisting conformers (B2 solution) or distinct aggregate types/domains (A3–B3 solids). The tert-butyl derivative A2 is non‑emissive in solution but exhibits aggregation‑induced emission in colloids and films. Amorphous A2 films that can be easily and uniformly applied at glass or metal surface, undergo mechano-induced crystallization upon gentle scratching, turning on bright luminescence precisely at the scratched area. This response is tuneable: films from CHCl3/n-hexane respond instantly; films from pure CHCl3 show delayed response upon n-hexane treatment, enabling both direct mechanical damage sensing and latent image encryption. The combination of tuneable response kinetics and multicolour emission upon excitation at different wavelengths is absent in conventional turn‑on mechanochromic sensors.

Olennikov V.E. , Kolybalov D.S. , Pylova E.K. , Ryadun A.A. , Konchenko S.N. , Sukhikh T.S.
Intra- and intermolecular excited state proton transfer in phenylbenzothiazole amides: excitation-controlled dual emission and a crystallization-based scratch sensor
Journal of Materials Chemistry C. 2026. V.14. N37. P.17567–17580. DOI: 10.1039/d6tc01887d WOS OpenAlex

Submitted:	Jun 9, 2026
Accepted:	Aug 7, 2026
Published online:	Aug 7, 2026
Published print:	Oct 1, 2026

≡ Web of science:	WOS:001858414200001
≡ OpenAlex:	W7201869202