Naslov
Excited State Intramolecular Proton Transfer (ESIPT) in Anthrol Carbaldehydes

Autori
Basarić, Nikola ; Chaiwongwattana, Sermsiri ; Došlić, Nađa ; Škalamera, Đani ; Bohne, Cornelia

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
28th International Conference on Photochemistry / ICP 2017 / Strasbourg, Francuska / - , 2017, 54-54

Skup
28th International Conference on Photochemistry / ICP 2017

Mjesto i datum
Strasbourg, Francuska, 16.07.2017. - 21.07.2017

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
excited state intramolecular proton transfer ; fluorescence spectroscopy, laser flash photolysis, qunatum chemical calculations
(excited state intramolecular proton transfer ; fluorescence spectroscopy, laser flash photolysis, qunatum chemical calculation)

Sažetak
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.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

POVEZANOST RADA