Quantum chemical elucidation of the turn-on luminescence mechanism in two new Schiff bases as selective chemosensors of Zn2+: Synthesis, theory and bioimaging applications

We report the synthesis and characterization of two new selective zinc sensors (S,E)-11-amino-8-((2,4-di-tert-butyl-1-hydroxybenzylidene) amino)-11-oxopentanoic acid (A) and (S,E)-11-amino-8-((8-hydroxybenzylidene)amino)-11-oxopentanoic acid (B) based on a Schiff base and an amino acid. The fluorescent probes, after binding to Zn2+ ions, presented an enhancement in fluorescent emission intensity up to 30 times (ϕ = A 50.10 and B 18.14%). The estimated LOD for compounds A and B was 1.17 and 1.20 μM respectively (mixture of acetonitrile : water 1 : 1). Theoretical research has enabled us to rationalize the behaviours of the two selective sensors to Zn2+ synthesized in this work. Our results showed that in the free sensors, PET and ESIPT are responsible for the quenching of the luminescence and that the turn-on of luminescence upon coordination to Zn2+ is mainly induced by the elimination of the PET, which is deeply analysed through EDA, NOCV, molecular structures, excited states and electronic transitions via TD-DFT computations. Confocal fluorescence microscopy experiments demonstrate that compound A could be used as a fluorescent probe for Zn2+ in living cells.

Notas

Indexación Scopus

Palabras clave

Fluorescence microscopy, Probes, Quantum chemistry, Confocal fluorescence microscopy, Electronic transition, Fluorescent emission, Fluorescent probes, Luminescence mechanisms, Selective sensors, Synthesis and characterizations, Theoretical research, Fluorescence

Citación

RSC Advances Volume 9, Issue 53, Pages 30778 - 30789 2019

DOI

10.1039/c9ra05010h

URI

https://repositorio.unab.cl/xmlui/handle/ria/47972

Colecciones

FCE - Artículos de Revista

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