Bodipy-squaraine triads: Preparation and study of the intramolecular energy transfer, charge separation and intersystem crossing
Authors: Dong Y., Iagatti A., Foggi P., Zhao J., Mazzone G., Xu K., Ji W., Di Donato M., Russo N.
Autors Affiliation: State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, E-208 West Campus, 2 Ling-Gong Road, Dalian, 116024, China; LENS (European Laboratory for Non-Linear Spectroscopy), via N. Carrara 1, Sesto Fiorentino, 50019, Italy; Dipartimento di Chimica ‘Ugo Shiff’, Università di Firenze, via della Lastruccia 3-13, Sesto Fiorentino, 50019, Italy; INO, Istituto Nazionale di Ottica, Largo Enrico Fermi 6, Florence, I-50125, Italy; Dipartimento di Chimica, Università degli Studi di Perugia, via Elce di Sotto 8, Perugia, 06123, Italy; ICCOM-CNR, via Madonna del Piano 10, Sesto Fiorentino, 50019, Italy; Dipartimento di Chimica e Tecnologie Chimiche, Università della Calabria, Arcavacata di Rende, I-87036, Italy
Abstract: Two triads (BDP-SQ and Styryl-BDP-SQ) were prepared with Bodipy, styrylBodipy and Squaraine (SQ) units. SQ shows unexpected efficient intersystem crossing (ISC. phi(T) = 50%), which is attributed to S-1 -> T-1 transition. In the two triads, the Forster Resonance Energy Transfer (FRET) direction, as well as the spatial localization of the T-1 state, was judiciously tuned. The cascade photophysical properties of the triads were studied with steady-state and time -resolved optical spectroscopies, as well as with electrochemical characterization and theoretical computations. We show that triplet state was produced in triad BDP-SQ upon photoexcitation, but in Styryl-BDP-SQ the fast FRET and the charge separation (CS) processes compete with the ISC of the SQ unit, and no triplet state was formed upon photoexcitation. The singlet energy transfer kinetics were found to be 1.6 and 0.6 ps, respectively and are solvent polarity dependent. Charge transfer was confirmed with ultrafast transient absorption spectroscopy. (C) 2017 Elsevier Ltd. All rights reserved.
Journal/Review: DYES AND PIGMENTS
Volume: 147 Pages from: 560 to: 572
More Information: We thank the NSFC (21473020, 21673031, 21273028, 21421005 and 21603021), Program for Changjiang Scholars and Innovative Research Team in University [IRT_13R06], the Fundamental Research Funds for the Central Universities (DUT16TD25, DUT15ZD224, DUT2016TB12) for financial support. This project has received funding from the European UnionKeyWords: Charge separation; Charge recombination; FRET; Intersystem crossing; Triplet stateDOI: 10.1016/j.dyepig.2017.08.028Citations: 3data from “WEB OF SCIENCE” (of Thomson Reuters) are update at: 2019-08-18References taken from IsiWeb of Knowledge: (subscribers only)Connecting to view paper tab on IsiWeb: Click hereConnecting to view citations from IsiWeb: Click here