Synthesis, photophysics of a novel green light emitting 1,3,4-oxadiazole and its application in FRET with ZnSe/ZnS QDs donor

Abstract

The design and synthesis of a novel molecule 2-(4-((E)-2-(5-((E)-4-(5-(4-tert-butylphenyl)-1,3,4-oxadiazol-2-yl)styryl)thiophen-2-yl)vinyl)-5-(4-tert-butylphenyl)1,3,4-oxadiazole (2TVPO) based on Donor-π-Acceptor strategy through the Wittig reaction as well as characterization by 1H, 13C NMR spectroscopy, high resolution mass spectrometry and FT-IR spectroscopy form the central theme of the present work. Thermal (TGA and DSC), photophysical and electrochemical properties have been studied in detail for this novel probe. In addition, fluorescence resonance energy transfer (FRET) employing steady state and time resolved spectroscopy methods has been studied using core-shell ZnSe/ZnS QDs (7 and 8nm) and 2TVPO fluorescent probe, respectively, as the energy donor and acceptor. Results of these studies reveal that (i) FRET pairs show a strong dipole-dipole interaction tendency to transfer energy from donor to acceptor; (ii) they possess high FRET efficiency and (iii) strong dependence of the acceptor emission on the overlap integral, quantum dot size and donor-acceptor distance. Further, the type of quenching is analyzed by Stern–Volmer plots.