Steric hindrances and spectral distributions affecting energy transfer rate: A comparative study on specifically designed donor-acceptor pairs
Year: 2020
Authors: Domenichini E.; Doria S.; Di Donato M.; Cupellini L.; Biagiotti G.; Iagatti A.; Bussotti L.; Mennucci B.; Cicchi S.; Foggi P.
Autors Affiliation: Univ Strasbourg, IPCMS, 23 Rue Du Loess, F-67034 Strasbourg, France; Univ Firenze, European Lab Non Linear Spect LENS, Via Nello Carrara 1, I-50019 Florence, Italy; CNR, Ist Ist Chim Composti OrganoMetall, ICCOM, Via Madonna Piano 10, I-50019 Florence, Italy; Univ Pisa, Dipartimento Chim & Chim Ind, Via G Moruzzi 13, I-56124 Pisa, Italy; Univ Firenze, Dipartimento Chim Ugo Schiff, Via Lastruccia 3-13, I-50019 Florence, Italy; CNR INO, Largo Fermi 6, I-50125 Florence, Italy; Univ Perugia, Dipartimento Chim Biol & Biotecnol, Via Elce Sotto 8, I-06100 Perugia, Italy.
Abstract: In this work the photophysics of four bichromophoric units was studied by means of static and time resolved spectroscopy, with the aim of disentangling the contribution of steric and electronic factors in regulating the efficiency of electronic energy transfer (EET). The newly synthesized dyads share the same acceptor moiety, a substituted BODIPY chromophore, and differ either in the donor or in the molecular bridge connecting the two units. The use of different linkers allows for tuning the conformational flexibility of the dyad, while changing the donor has an influence on the electronic coupling and spectral overlap between the two chromophores. The efficiency of energy transfer is extremely high in all the four dyads and can be modelled within the frame of the Förster equation. In the special case of a dimeric donor, a theoretical analysis was performed to further support the experimental findings. Geometry optimization at DFT level indicated that different conformations with similar energy can exist in solution, explaining the observed multi-exponential EET. Furthermore, energy transfer rates, computed at DFT level, resulted in optimal agreement with the experimental ones. Our analysis allowed to conclude that, in case of the studied systems, steric hindrance and donor-acceptor relative orientations plays a prominent role in regulating the EET dynamics, even overcoming electronic effects.
Journal/Review: DYES AND PIGMENTS
Volume: 174 Pages from: 108010-1 to: 108010-9
More Information: This work was supported by the European Union, through the Horizon 2020 Research and Innovation Programme (RIA “Laserlab-Europe”, n. 654148).
The authors acknowledge the support and the use of resources of Instruct-ERIC, a Landmark ESFRI project, and specifically the CERM/CIRMMP Italy Centre.KeyWords: Non linear spectroscopy; dyad; chromophores; transient absorption; excited-state; bodipy; conversion; photodimerization; complexes; dynamics; solvent; dyesDOI: 10.1016/j.dyepig.2019.108010ImpactFactor: 4.889Citations: 1data from “WEB OF SCIENCE” (of Thomson Reuters) are update at: 2024-11-24References taken from IsiWeb of Knowledge: (subscribers only)Connecting to view paper tab on IsiWeb: Click hereConnecting to view citations from IsiWeb: Click here
