Premium
A Photochromic Benzothiadiazole‐Diarylethene System with Tunable On/Off Fluorescence Modulation
Author(s) -
Ziebart Nandor,
Schröder Fanny,
RückBraun Karola
Publication year - 2019
Publication title -
chemphotochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.13
H-Index - 18
ISSN - 2367-0932
DOI - 10.1002/cptc.201800230
Subject(s) - fluorophore , photochemistry , photoisomerization , fluorescence , diarylethene , conjugated system , chemistry , photochromism , thiophene , förster resonance energy transfer , photobleaching , materials science , organic chemistry , polymer , optics , isomerization , physics , catalysis
Organic molecules with photoswitchable emission properties are of interest in the optical devices field. We present herein in‐solution studies for two dimethoxydithienylethene‐fluorophore (DTE‐fluorophore) conjugates with a carboxylic acid anchor group attachable to semiconductor surfaces (DTE‐BODIPY and BTD‐DTE, where BTD=benzothiadiazole). Both conjugates show almost quantitative reversible photoisomerization between open (OF) and closed forms (CF). With excitation of the fluorophores, both conjugates emit fluorescence with highly solvent‐dependent OFs (BTD‐DTE>DTE‐BODIPY) and minor solvent‐dependent CFs. In the polar solvent MeCN for BTD‐DTE a TICT state is clearly observed, which will be located in the twisted conjugated structure of the benzoic acid‐BTD‐fluorophore‐methoxy‐thiophene unit. BTD‐DTE shows positive solvatofluorochromism with a decrease of fluorescence quantum yields by increasing the Lippert orientation polarizability function ( Δf ) verified in Lippert‐Mataga plots. This leads to solvent dependent on‐off/off‐on (CF‐OF) emission modulation by Förster resonance energy transfer (FRET) with well‐separated emission bands for BTD‐DTE.