title: Optimization of hydrogen-evolving photochemical molecular devices.
abstract: A molecular photocatalyst consisting of a Ru(II) photocenter, a tetrapyridophenazine bridging ligand, and a PtX2 (X=Cl or I) moiety as the catalytic center functions as a stable system for light-driven hydrogen production. The catalytic activity of this photochemical molecular device (PMD) is significantly enhanced by exchanging the terminal chlorides at the Pt center for iodide ligands. Ultrafast transient absorption spectroscopy shows that the intramolecular photophysics are not affected by this change. Additionally, the general catalytic behavior, that is, instant hydrogen formation, a constant turnover frequency, and stability are maintained. Unlike as observed for the Pd analogue, the presence of excess halide does not affect the hydrogen generation capacity of the PMD. The highly improved catalytic efficiency is explained by an increased electron density at the Pt catalytic center, this is confirmed by DFT studies.
authors: Ulm University, Institute of Inorganic Chemistry Materials and Catalysis, Albert-Einstein-Allee 11, 89081 Ulm (Germany).
authors: Michael G
authors: MG
authors: Pfeffer
authors: Ulm University, Institute of Inorganic Chemistry Materials and Catalysis, Albert-Einstein-Allee 11, 89081 Ulm (Germany).
authors: Tanja
authors: T
authors: Kowacs
authors: Leibniz Institute of Photonic Technology, Albert-Einstein-Strasse 9, Jena (Germany).
authors: Maria
authors: M
authors: Wächtler
authors: Gdansk University of Technology, Faculty of Applied Physics and Mathematics, Narutowicza 11/12, 80233 Gdansk (Poland).
authors: Julien
authors: J
authors: Guthmuller
authors: Leibniz Institute of Photonic Technology, Albert-Einstein-Strasse 9, Jena (Germany).|Friedrich-Schiller-University Jena, Institute of Physical Chemistry and Abbe Center of Photonics, Helmholtzweg 4, 07743 Jena (Germany).
authors: Benjamin
authors: B
authors: Dietzek
authors: SRC for Solar Energy Conversion, School of Chemical Sciences, Dublin City University, Glasnevin, Dublin 9, Dublin (Ireland).
authors: Johannes G
authors: JG
authors: Vos
authors: Ulm University, Institute of Inorganic Chemistry Materials and Catalysis, Albert-Einstein-Allee 11, 89081 Ulm (Germany). sven.rau@uni-ulm.de.
authors: Sven
authors: S
authors: Rau
keywords: electron density; hydrogen production; iodide ligands; photocatalysis; platinum