title: Ultrafast intramolecular relaxation and wave-packet motion in a ruthenium-based supramolecular photocatalyst.
abstract: The hydrogen-evolving photocatalyst [(tbbpy)2 Ru(tpphz)Pd(Cl)2 ](2+) (tbbpy=4,4'-di-tert-butyl-2,2'-bipyridine, tpphz=tetrapyrido[3,2-a:2',3'-c:3'',2''-h:2''',3'''-j]phenazine) shows excitation-wavelength-dependent catalytic activity, which has been correlated to the localization of the initial excitation within the coordination sphere. In this contribution the excitation-wavelength dependence of the early excited-state relaxation and the occurrence of vibrational coherences are investigated by sub-20 fs transient absorption spectroscopy and DFT/TDDFT calculations. The comparison with the mononuclear precursor [(tbbpy)2 Ru(tpphz)](2+) highlights the influence of the catalytic center on these ultrafast processes. Only in the presence of the second metal center, does the excitation of a (1) MLCT state localized on the central part of the tpphz bridge lead to coherent wave-packet motion in the excited state.
authors: Leibniz-Institute of Photonic Technology Jena (IPHT) e.V. Albert-Einstein-Str. 9, 07745, Jena (Germany), Fax: (+49) 3641-206390; Institute of Physical Chemistry and Abbe Center of Photonics, Friedrich-Schiller University Jena, Helmholtzweg 4, 07743 Jena (Germany).
authors: Maria
authors: M
authors: Wächtler
authors: Julien
authors: J
authors: Guthmuller
authors: Stephan
authors: S
authors: Kupfer
authors: Margherita
authors: M
authors: Maiuri
authors: Daniele
authors: D
authors: Brida
authors: Jürgen
authors: J
authors: Popp
authors: Sven
authors: S
authors: Rau
authors: Giulio
authors: G
authors: Cerullo
authors: Benjamin
authors: B
authors: Dietzek
keywords: DFT; coherent vibrational motion; photophysics; ruthenium; time-resolved spectroscopy