title: Porphyrin Metalation at the MgO Nanocube/Toluene Interface.
abstract: Molecular insights into porphyrin adsorption on nanostructured metal oxide surfaces and associated ion exchange reactions are key to the development of functional hybrids for energy conversion, sensing, and light emission devices. Here we investigated the adsorption of tetraphenyl-porphyrin (2HTPP) from toluene solution on two types of MgO powder. We compare MgO nanocubes with an average size d < 10 nm and MgO cubes with 10 nm ≤ d ≤ 1000 nm. Using molecular spectroscopy techniques such as UV/vis transmission and diffuse reflectance (DR), photoluminescence (PL), and diffuse reflectance infrared Fourier-transform (DRIFT) spectroscopy in combination with structural characterization techniques (powder X-ray diffraction and transmission electron microscopy, TEM), we identified a new room temperature metalation reaction that converts 2HTPP into magnesium tetraphenyl-porphyrin (MgTPP). Mg(2+) uptake from the MgO nanocube surfaces and the concomitant protonation of the oxide surface level off at a concentration that corresponds to roughly one monolayer equivalent adsorbed on the MgO nanocubes. Larger MgO cubes, in contrast, show suppressed exchange, and only traces of MgTPP can be detected by photoluminescence.
authors.affiliation: Department of Materials Science and Physics, Paris Lodron University of Salzburg , Hellbrunnerstrasse 34/III, A-5020 Salzburg, Austria.
authors.forename: Johannes
authors.initials: J
authors.lastname: Schneider
authors.affiliation: Lehrstuhl für Physikalische Chemie II, Friedrich-Alexander-Universität Erlangen-Nürnberg , Egerlandstraße 3, 91058 Erlangen, Germany.
authors.forename: Fabian
authors.initials: F
authors.lastname: Kollhoff
authors.affiliation: University Service Center for Transmission Electron Microscopy, Vienna University of Technology , Wiedner Hauptstrasse 8-10, A-1040 Vienna, Austria.
authors.forename: Johannes
authors.initials: J
authors.lastname: Bernardi
authors.affiliation: Lehrstuhl für Physikalische Chemie II, Friedrich-Alexander-Universität Erlangen-Nürnberg , Egerlandstraße 3, 91058 Erlangen, Germany.
authors.forename: Andre
authors.initials: A
authors.lastname: Kaftan
authors.affiliation: Lehrstuhl für Physikalische Chemie II, Friedrich-Alexander-Universität Erlangen-Nürnberg , Egerlandstraße 3, 91058 Erlangen, Germany.|Erlangen Catalysis Resource Center and Interdisciplinary Center for Interface-Controlled Processes, Friedrich-Alexander-Universität Erlangen-Nürnberg , 91058 Erlangen, Germany.
authors.forename: Jörg
authors.initials: J
authors.lastname: Libuda
authors.affiliation: Department of Materials Science and Physics, Paris Lodron University of Salzburg , Hellbrunnerstrasse 34/III, A-5020 Salzburg, Austria.
authors.forename: Thomas
authors.initials: T
authors.lastname: Berger
authors.affiliation: Lehrstuhl für Physikalische Chemie II, Friedrich-Alexander-Universität Erlangen-Nürnberg , Egerlandstraße 3, 91058 Erlangen, Germany.
authors.forename: Mathias
authors.initials: M
authors.lastname: Laurin
authors.affiliation: Department of Materials Science and Physics, Paris Lodron University of Salzburg , Hellbrunnerstrasse 34/III, A-5020 Salzburg, Austria.
authors.forename: Oliver
authors.initials: O
authors.lastname: Diwald
keywords: MgO cubes; dye adsorption; hybrid materials; molecular spectroscopies; porphyrin metalation; solid−liquid interface