Combined Experimental and Theoretical Study of Efficient and Ultrafast Energy Transfer in a Molecular Dyad

Year: 2014

Authors: Di Donato M., Iagatti A., Lapini A, Foggi P., Cicchi S., Lascialfari L., Fedeli S., Caprasecca S., Mennucci B.

Autors Affiliation: LENS (European Laboratory for Non Linear Spectroscopy) via N. Carrara 1, 50019 Sesto Fiorentino (FI), Italy;
Dipartimento di Chimica “Ugo Schiff”, Universita’ di Firenze, via della Lastruccia 13, 50019 Sesto Fiorentino (FI), Italy;
INO (Istituto Nazionale di Ottica), Largo Fermi 6, 50125 Firenze, Italy;
Dipartimento di Chimica, Università di Perugia, via Elce di Sotto 8, 06123 Perugia, Italy;
Dipartimento di Chimica e Chimica Industriale, Università di Pisa, via Risorgimento 35, I-56126 Pisa, Italy

Abstract: We have characterized the dynamics and the efficiency of electronic energy transfer (EET) in a newly synthesized molecular dyad, composed of a styryl-pyridinium donor and a BODIPY acceptor. The kinetics of the process has been studied with femtosecond transient absorption spectroscopy in different solvents. In all the analyzed media EET is quantitative and very fast, as we find that almost 70% of the overall excitation energy is transferred from the donor to the acceptor on a subpicosecond time scale. The experimental measurements have been supported by a theoretical analysis; the electronic couplings between the donor and acceptor moieties have been calculated at the (TD)DFT level and complemented by a conformational analysis of the full dyad. The computed energy transfer times are in good agreement with the experimental values; this allowed us to verify the correctness of the Forster equation, demonstrating that, although EET in the examined system occurs on an ultrafast time scale, the approximations introduced in the case of the weak coupling regime remain valid.

Journal/Review: JOURNAL OF PHYSICAL CHEMISTRY C

Volume: 118 (41)      Pages from: 23476  to: 23486

More Information: The authors gratefully acknowledge support from the Italian MIUR: program FIRB \”Futuro in Ricerca 2010\” grant RBFR10Y5VW to M.D.D. and RBFR109ZHQ supporting project EFOR-CABIR L. 191/2009 art. 2 comma 44, and grant FIRB RBAP11ETKA_002 \’Approcci nanotecnologici per la teragnostica dei tumori\’ to S. Cicchi. B.M. and S. Caprasecca thank the ERC for financial support in the framework of the Starting Grant (EnLight -277755).
KeyWords: Energy Transfer; Ultrafast Spectroscopy; Forster; Reaction center mimicry; Fluorescence quantum yield
DOI: 10.1021/jp505957q

Citations: 26
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