Excited State Intramolecular Proton Transfer (ESIPT) in Anthrol Carbaldehydes (CROSBI ID 650713)
Prilog sa skupa u zborniku | sažetak izlaganja sa skupa | međunarodna recenzija
Podaci o odgovornosti
Basarić, Nikola ; Chaiwongwattana, Sermsiri ; Došlić, Nađa ; Škalamera, Đani ; Bohne, Cornelia
engleski
Excited State Intramolecular Proton Transfer (ESIPT) in Anthrol Carbaldehydes
ESIPT has been intensively investigated over five decades because of its fundamental aspect in chemistry and biology, [1] as well as numerous applications in material science, [2] sensing and bioimaging.[3] The most common acidic group in ESIPT reactions is phenolic OH, [4] whereas the basic site is usually a carbonyl group.[5] Thus, among the first molecules that were experimentally found to undergo ESIPT were simple salicaldehyde derivatives. The reaction scope has later been extended to naphthol carbaldehyde derivatives.[6] However, to date, ESIPT in anthrol carbaldehydes has not been documented. Photophysical properties and reactivity in ESIPT for anthrol carbaldehydes 1-5 have been investigated computationally and experimentally by steady-state and time-resolved fluorescence and laser flash photolysis (LFP). Contrary to analogous naphthol derivatives, 1, 2-disubstituted anthrol carbaldehydes 1 and 2 are not ESIPT reactive. The main deactivation channels from S1 for 1 and 2 are fluorescence (ΦF = 0.1-0.2) and ISC to an almost isoenergetic T2 state. The triplet states from 1 and 2 were detected by LFP. On the contrary, 2, 3-disubstituted anthrols 3-5 undergo efficient barrierless ultrafast ESIPT. However, the typical dual emission from locally excited states and ESIPT tautomers were not observed since ESIPT proceeds via a conical intersection with S0 delivering keto-tautomer in the hot ground state. Therefore, anthrols 3-5 are about ten times less fluorescent, and their emission originates from less-populated conformers that cannot undergo ESIPT. Keto-tautomers for 3-5 were detected in CH3CN by LFP (λmax = 370 nm, τ = 30-40 ns). The difference in ESIPT reactivity for 1-3 was fully disclosed by calculations at ADC(2)/aug-cc-pVDZ level of theory, and particularly, by calculating the charge redistribution upon excitation to S1. Only 2, 3-disubstituted anthrols exhibit polarization in S1 that increases electron density on carbonyl and decreases on phenolic OH, setting the stage for ultrafast ESIPT.
excited state intramolecular proton transfer ; fluorescence spectroscopy, laser flash photolysis, qunatum chemical calculation
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Podaci o prilogu
54-54.
2017.
objavljeno
Podaci o matičnoj publikaciji
28th International Conference on Photochemistry / ICP 2017 / Strasbourg, Francuska
Podaci o skupu
28th International Conference on Photochemistry / ICP 2017
poster
16.07.2017-21.07.2017
Strasbourg, Francuska