title: Functionalized Porphyrins on an Atomically Defined Oxide Surface: Anchoring and Coverage-Dependent Reorientation of MCTPP on Co3O4(111).
abstract: We have studied the adsorption of tetraphenylporphyrin (2HTPP) and its carboxylated counterpart mono-para-carboxyphenyltriphenylporphyrin (MCTPP) on an atomically defined Co3O4(111) film under ultrahigh vacuum (UHV) conditions. Using time-resolved infrared reflection absorption spectroscopy (TR-IRAS), we show that 2HTPP adsorbs molecularly in a flat-lying orientation, whereas MCTPP binds to the surface via formation of a chelating bidentate carboxylate upon deposition at 400 K. Combining TR-IRAS and density-functional theory (DFT), we determine the molecular tilting angle as a function of coverage. We show that the MCTPP adsorption geometry changes from a nearly flat-lying orientation (tilting angle <30°) at low coverage to a nearly perfectly upright-standing orientation (tilting angle of approximately 80°) in the full monolayer.
authors.affiliation: Lehrstuhl für Physikalische Chemie II, ‡Lehrstuhl für Theoretische Chemie, and §Erlangen Catalysis Resource Center and Interdisciplinary Center for Interface-Controlled Processes, Friedrich-Alexander-Universität Erlangen-Nürnberg , Egerlandstraße 3, D-91058 Erlangen, Germany.
authors.forename: Kristin
authors.initials: K
authors.lastname: Werner
authors.affiliation: Lehrstuhl für Physikalische Chemie II, ‡Lehrstuhl für Theoretische Chemie, and §Erlangen Catalysis Resource Center and Interdisciplinary Center for Interface-Controlled Processes, Friedrich-Alexander-Universität Erlangen-Nürnberg , Egerlandstraße 3, D-91058 Erlangen, Germany.
authors.forename: Susanne
authors.initials: S
authors.lastname: Mohr
authors.affiliation: Lehrstuhl für Physikalische Chemie II, ‡Lehrstuhl für Theoretische Chemie, and §Erlangen Catalysis Resource Center and Interdisciplinary Center for Interface-Controlled Processes, Friedrich-Alexander-Universität Erlangen-Nürnberg , Egerlandstraße 3, D-91058 Erlangen, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Schwarz
authors.affiliation: Lehrstuhl für Physikalische Chemie II, ‡Lehrstuhl für Theoretische Chemie, and §Erlangen Catalysis Resource Center and Interdisciplinary Center for Interface-Controlled Processes, Friedrich-Alexander-Universität Erlangen-Nürnberg , Egerlandstraße 3, D-91058 Erlangen, Germany.
authors.forename: Tao
authors.initials: T
authors.lastname: Xu
authors.affiliation: Lehrstuhl für Physikalische Chemie II, ‡Lehrstuhl für Theoretische Chemie, and §Erlangen Catalysis Resource Center and Interdisciplinary Center for Interface-Controlled Processes, Friedrich-Alexander-Universität Erlangen-Nürnberg , Egerlandstraße 3, D-91058 Erlangen, Germany.
authors.forename: Max
authors.initials: M
authors.lastname: Amende
authors.affiliation: Lehrstuhl für Physikalische Chemie II, ‡Lehrstuhl für Theoretische Chemie, and §Erlangen Catalysis Resource Center and Interdisciplinary Center for Interface-Controlled Processes, Friedrich-Alexander-Universität Erlangen-Nürnberg , Egerlandstraße 3, D-91058 Erlangen, Germany.
authors.forename: Tibor
authors.initials: T
authors.lastname: Döpper
authors.affiliation: Lehrstuhl für Physikalische Chemie II, ‡Lehrstuhl für Theoretische Chemie, and §Erlangen Catalysis Resource Center and Interdisciplinary Center for Interface-Controlled Processes, Friedrich-Alexander-Universität Erlangen-Nürnberg , Egerlandstraße 3, D-91058 Erlangen, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Görling
authors.affiliation: Lehrstuhl für Physikalische Chemie II, ‡Lehrstuhl für Theoretische Chemie, and §Erlangen Catalysis Resource Center and Interdisciplinary Center for Interface-Controlled Processes, Friedrich-Alexander-Universität Erlangen-Nürnberg , Egerlandstraße 3, D-91058 Erlangen, Germany.
authors.forename: Jörg
authors.initials: J
authors.lastname: Libuda