1337570-03-2Relevant academic research and scientific papers
Fundamentally Different Distance Dependences of Electron-Transfer Rates for Low and High Driving Forces
Neumann, Svenja,Wenger, Oliver S.
, p. 855 - 860 (2019/01/11)
The distance dependences of electron-transfer rates (kET) in three homologous series of donor-bridge-acceptor compounds with reaction free energies (ΔGET0) of ca. -1.2, -1.6, and -2.0 eV for thermal charge recombination after initial photoinduced charge separation were studied by transient absorption spectroscopy. In the series with low driving force, the distance dependence is normal and kET decreases upon donor-acceptor distance (rDA) elongation. In the two series with higher driving forces, kET increases with increasing distance over a certain range. This counterintuitive behavior can be explained by a weakly distance-dependent electronic donor-acceptor coupling (HDA) in combination with an increasing reorganization energy (λ). Our study shows that highly exergonic electron transfers can have distance dependences that differ drastically from those of the more commonly investigated weakly exergonic reactions.
Increasing Electron-Transfer Rates with Increasing Donor-Acceptor Distance
Kuss-Petermann, Martin,Wenger, Oliver S.
, p. 815 - 819 (2016/02/23)
Electron transfer can readily occur over long (≥ 15 ?) distances. Usually reaction rates decrease with increasing distance between donors and acceptors, but theory predicts a regime in which electron-transfer rates increase with increasing donor-acceptor separation. This counter-intuitive behavior can result from the interplay of reorganization energy and electronic coupling, but until now experimental studies have failed to provide unambiguous evidence for this effect. We report here on a homologous series of rigid rodlike donor-bridge-acceptor compounds in which the electron-transfer rate increases by a factor of 8 when the donor-acceptor distance is extended from 22.0 to 30.6 ?, and then it decreases by a factor of 188 when the distance is increased further to 39.2 ?. This effect has important implications for solar energy conversion.
Microsecond charge recombination in a linear triarylamine-Ru(bpy) 32+-anthraquinone triad
Hankache, Jihane,Wenger, Oliver S.
, p. 10145 - 10147 (2011/10/09)
Linear triads with ruthenium photosensitizers are frequently based on the Ru(terpyridine)22+ unit. We report on vectorial photoinduced electron transfer in a linear triad based on the Ru(bipyridine)32+ photosensitizer. Electron-hole separation over a 22 A-distance is established with a quantum yield greater than 64% and persists for 1.3 μs in acetonitrile. The Royal Society of Chemistry 2011.
