Excitation Power Modulates Energy‐Transfer Dynamics in a Supramolecular RuII‐FeII‐RuII Triad. Issue 20 (7th September 2017)

• Record Type: Journal Article
• Authors: Kübel, Joachim; Wächtler, Maria; Dietzek, Benjamin
• Is Part Of: Chemphyschem. Volume 18:Issue 20(2017)
• Page Start: 2899
• Page End: 2907
• Publication Date: 2017-09-07
• Subjects: energy transfer -- photophysics -- photosynthesis -- time-resolved spectroscopy -- transition metals; Chemistry, Physical and theoretical -- Periodicals; 541.05
• DOI: 10.1002/cphc.201700710
• Languages: English
• ISSNs: 1439-4235

Abstract

Abstract: Multichromophoric arrays are key to light harvesting in natural and artificial photosynthesis. A trinuclear, symmetric Ru II ‐Fe II ‐Ru II triad may resemble a light‐harvesting model system in which excitation energy from donor units (Ru‐terpyridine fragments) is efficiently transferred to the acceptor (the Fe‐terpyridine fragment). The photoinduced dynamics after simultaneous excitation of more than a single chromophoric unit (donor/acceptor) at varying excitation fluence is investigated in this contribution. Data suggests that energy transfer is decelerated if the acceptor states (on the Fe II unit) are not depopulated fast enough. As a consequence, the lifetime of a high‐lying excited state (centered on either of the Ru II units) is prolonged. A kinetic model is suggested to account for this effect. Although the proposed model is specifically adopted to account for the experimental data reported here, it might be generalized to other situations in which multiple energy or electron donors are covalently linked to a single acceptor site, a situation of interest in contemporary artificial photosynthesis. Abstract : Very excited : Energy transfer from ruthenium to iron in a trinuclear complex (see picture; EnT=energy transfer) is slowed down at elevated photon densities, at which the donor and acceptor in the same molecule are excited.