Synthesis and Manifold But Controllable Emission Switching of Stilbene-Appended Polyaromatic Terpyridine Derivatives Via Aggregation and Trans-Cis Isomerization
32 Pages Posted: 28 Feb 2022
Abstract
We designed in this work a new series of stilbene-appended terpyridine systems covalently coupled with anthracene, naphthalene and pyrene moieties which can exhibit multiple yet controllable photo-switching behaviors under divergent conditions. Upon aggregation, these emissive compounds display either remarkable blue-shifted emission enhancement or emission quenching with red-shift, depending upon the nature of solvent. Both free- as well as aggregated forms of the compounds undergo trans→cis isomerization upon treating with visible light, accompanied with significant alteration in their spectral behaviors. The reverse cis→trans process is achieved on keeping the photolyzed solutions in dark. Hence, ‘on-off’ and ‘off-on’ emission switching is feasible upon successive exposure to light and keeping in dark. A gradual decrease in rate constant and quantum yield of photoisomerisation was observed with increase in extent of aggregation. Additionally, DFT and TD-DFT calculations are also carried out to interpret experimental spectral bands of the compounds.
Keywords: AIEE, Aggregation Induced Blue Shifted Emission, Trans-cis Photoisomerization, Photo-switching, DFT-TDDFT
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