title: π-Stacking attraction vs. electrostatic repulsion: competing supramolecular interactions in a tpphz-bridged Ru(ii)/Au(iii) complex.
abstract: The synthesis and characterization of a mixed metal ruthenium(ii)/gold(iii) complex bridged by tetrapyridophenazine (tpphz) are described. It is isostructural and isoelectronic to the well-known photocatalysts with palladium(ii) or platinum(ii). Concentration dependent (1)H-NMR spectroscopy and XRD studies show that the electrostatic repulsion between the gold(iii) moieties exceeds the attractive π-stacking interaction. Theoretical calculations based on the new structural data confirm an increased positive charge on the bridging ligand as well as significantly altered orbital symmetry as compared to the previously investigated palladium(ii) complex. This is the first example of a tpphz ruthenium(ii) complex where π-stacking is completely inhibited. The detailed investigation of the solid-state structure showed for the first time in bimetallic tpphz bridged complexes no significant torsion within the bridging ligand itself. Although catalytic performance for proton reduction by gold(iii) is naturally not observed, its photochemical decomposition in colloidal gold particles could be shown by TEM and DLS.
authors.affiliation: Institute for Inorganic Chemistry I, Ulm University, Albert-Einstein-Allee 11, D-89081 Ulm, Germany. sven.rau@uni-ulm.de.
authors.forename: Dieter
authors.initials: D
authors.lastname: Sorsche
authors.affiliation: Institute for Inorganic Chemistry I, Ulm University, Albert-Einstein-Allee 11, D-89081 Ulm, Germany. sven.rau@uni-ulm.de.
authors.forename: Markus
authors.initials: M
authors.lastname: Schaub
authors.affiliation: Institute of Inorganic and General Chemistry, Egerlandstr. 1, D-91058 Erlangen, Germany.
authors.forename: Frank W
authors.initials: FW
authors.lastname: Heinemann
authors.affiliation: Institute for Inorganic Chemistry I, Ulm University, Albert-Einstein-Allee 11, D-89081 Ulm, Germany. sven.rau@uni-ulm.de.
authors.forename: Johannes
authors.initials: J
authors.lastname: Habermehl
authors.affiliation: Institute of Energy and Climate Research, Electrochemical Process Engineering (IEK-3), Wilhelm-Johnen-Straße, D-52428 Jülich, Germany.
authors.forename: Susanne
authors.initials: S
authors.lastname: Kuhri
authors.affiliation: Friedrich-Alexander-Universität Erlangen/Nürnberg, Department Chemie und Pharmazie, Lehrstuhl für Physikalische Chemie I, Egerlandstraße 3, D-91058 Erlangen, Germany.
authors.forename: Dirk
authors.initials: D
authors.lastname: Guldi
authors.affiliation: Faculty of Applied Physics and Mathematics, Gdansk University of Technology, Narutowicza 11/12, 80-233 Gdansk, Poland.
authors.forename: Julien
authors.initials: J
authors.lastname: Guthmuller
authors.affiliation: Institute for Inorganic Chemistry I, Ulm University, Albert-Einstein-Allee 11, D-89081 Ulm, Germany. sven.rau@uni-ulm.de.
authors.forename: Sven
authors.initials: S
authors.lastname: Rau