Tuning ESIPT fluorophores into dual emitters

Abstract

Using first-principle approaches, we show how ESIPT can be controlled by fine-tuning of substituents, hence leading to new dual emitters.

On the Fine‐Tuning of the Excited‐State Intramolecular Proton Transfer (ESIPT) Process in 2‐(2′‐Hydroxybenzofuran)benzazole (HBBX) Dyes

“…[22] However,acooperative effect between an acceptor on the benzoxazole side and astrong donor on the phenol is necessary for the observation of significant ESIPTfrustration and asubsequent intense dual emission, as in dye 21.I ti sa lso worth noting that the presenceo fa na lkoxy donor in lieu of an amino donor does not perturb the main emission features (F = 3a nd 6%, s = 0.4 and0 .3 ns for 16 and 20,r espectively, vs. F = 7a nd 6%, s = 0.7 and 0.7 ns for 21 and 22,r espectively). This K* band does not undergo any major change in the series (l em = 568 and 565 nm for 16 and 20 in toluene, respectively).…”

“…[22] The mosts triking observation in the studied HBBX series lies in the opticalp roperties of HBBI 14,w hichc onvey precious insight into the importance of the heteroelement for efficient optimization of the dyes. Introduction of an EA in HBBT 3 and 4 led to the appearance of ad ual E*/K* emission with av ery weak E*/K* intensity ratio.…”

“…[18,19,22] Activation barrierv alues that are too high would limit the E*!K* reaction, whereas values of DG ES that are too negative/positive would overstabilize K*/E* and lead to as ingle emission. [18,19,22] Activation barrierv alues that are too high would limit the E*!K* reaction, whereas values of DG ES that are too negative/positive would overstabilize K*/E* and lead to as ingle emission.…”

Unraveling the Mechanisms of the Excited‐State Intermolecular Proton Transfer (ESPT) for a D‐π‐A Molecular Architecture

“…Elemental analysis calcd (%) for C 11 The solution was heated to reflux at 80 8Cf or 8h.A fter cooling to room temperature, ag rayish powder of TIMDP was precipitated, which was collected by filtration and washed with ethanol (yield = 92 %, based on C 9 H 10 O 4 ).…”

A quantum-chemical insight into the tunable fluorescence color and distinct photoisomerization mechanisms between a novel ESIPT fluorophore and its protonated form

“…In the case in which the energy barrier for the ESIPT reaction is low enough or even zero (that is, the ESIPT process is barrierless), ESIPT can take place with an extremely ultrafast rate so that the steady-state fluorescence spectra only exhibit a single emission band arising from K* [10][11][12]. In numerous cases, however, a high energy barrier for the proton transfer process is clearly involved, and hence both E* and K* emissions can contribute to the experimental fluorescence spectra, that is, so-called dual fluorescence emission [13][14][15][16]. After K* → K fluorescence emission, the transient K species can return back to the more stable E conformer via a reverse ground-state hydrogen transfer (RGSHT) reaction in a facile tautomerization.…”