ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Photochromic properties of triangle terthiophene- and triphenylamine-configured diarylethene type dye with propeller-like conformation

Yucheng Kong, Xuyang Liu, Wenjuan Jiang, and Xiaochuan Li

NMPA Key Laboratory for Research and Evaluation of Innovative Drug, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, People’s Republic of China

E-mail: lixiaochuan@htu.edu.cn

Received: 8 March 2024  Accepted: 28 January 2025

Abstract:

A photochromic dye (TPDA) with helical structure was configured by attaching triangle terthiophene to triphenylamine units. It exhibits typical photochromic behavior when irradiated with UV (390 nm)/visible light (> 410 nm). Moreover, TPDA in tetrahydrofuran (THF) can be switched alternately between color and colorless state. In addition, it exhibits highly emissive character in THF and could emit bright blue fluorescence by UV irradiation. And the fluorescence emission efficiency was estimated to be 0.41. Under the UV light irradiation, a ring-closure reaction occurred and the blue fluorescence was quenched effectively at the same time. At photo-stationary state, the quantum yield was lowered to 0.10. Therefore, a switch controllable fluorescence “on–off” molecular system was developed when light irradiation cycle established (UV/visible light). Optimization of the dye structure was performed using density functional theory at the DND/B3LYP level of theory. The structural analysis reveals that the shorter distance between reactive atoms (< 4.2 Å) in the triangle terthiophene unit promotes the smoothly photochromism of TPDA.

Keywords: Photochromic behavior; Triangle terthiophene; Triphenylamine; Fluorescence emission efficiency; Switch controllable fluorescence “on–off”

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-025-03934-8

Chemical Papers 79 (4) 2401–2409 (2025)