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Baronio S, Bassotti M, Armillotta F, Frampton E, Vinogradov NA, Schio L, Floreano L, Verdini A, Vesselli E. Stabilization versus competing de-metalation, trans-metalation and (cyclo)-dehydrogenation of Pd porphyrins at a copper surface. NANOSCALE 2024; 16:13416-13424. [PMID: 38895999 DOI: 10.1039/d4nr00699b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
Metal-porphyrins are studied intensively due their potential applications, deriving from the variety of electronic and chemical properties, tunable by selecting metal centers and functional groups. Metalation, de- and trans-metalation processes are fundamental in this sense to investigate both the synthesis and the stability of these molecular building blocks. More specifically, Pd coordination in tetrapyrroles revealed to be potentially interesting in the fields of cancer therapy, drug delivery and light harvesting. Thus, we focused on the stability of palladium tetraphenyl porphyrins (PdTPPs) on a copper surface by means of combined spectroscopy and microscopy approaches. We find that PdTPPs undergo coverage-dependent trans-metalation accompanied by steric rearrangements already at room temperature, and fully trans-metalate to CuTPPs upon mild annealing. Side reactions such as (cyclo)-dehydrogenation and structural reorganization affect the molecular layer, with Pd-Cu alloying and segregation occurring at higher temperature. Instead, oxygen passivation of the Cu support prevents the metal-involving reactions, thus preserving the layer and increasing the chemical and temperature stability of the Pd porphyrins.
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Affiliation(s)
| | - Mattia Bassotti
- Department of Physics, University of Perugia, Perugia, Italy
| | - Francesco Armillotta
- Department of Physics, University of Trieste, Trieste, Italy
- Institute of Physics Ecole Polytechnique Fédérale de Lausanne (EPFL) Station 3, Lausanne, Switzerland
| | | | | | - Luca Schio
- CNR-IOM - Istituto Officina dei Materiali, Area Science Park, Trieste, Italy.
| | - Luca Floreano
- CNR-IOM - Istituto Officina dei Materiali, Area Science Park, Trieste, Italy.
| | - Alberto Verdini
- Department of Physics, University of Perugia, Perugia, Italy
- CNR-IOM - Istituto Officina dei Materiali, Area Science Park, Trieste, Italy.
| | - Erik Vesselli
- Department of Physics, University of Trieste, Trieste, Italy
- CNR-IOM - Istituto Officina dei Materiali, Area Science Park, Trieste, Italy.
- Center for Energy, Environment and Transport Giacomo Ciamician, University of Trieste, Trieste, Italy
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2
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Pijeat J, Chaussy L, Simoës R, Isopi J, Lauret J, Paolucci F, Marcaccio M, Campidelli S. Thermally Induced Synthesis of Anthracene-, Pyrene- and Naphthalene-Fused Porphyrins. ChemistryOpen 2021; 10:997-1003. [PMID: 34617692 PMCID: PMC8495684 DOI: 10.1002/open.202100201] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 09/07/2021] [Indexed: 12/02/2022] Open
Abstract
The synthesis of π-extended porphyrins containing anthracenyl moieties still represents an important challenge. Here, we report on the synthesis of a series of unsubstituted naphthyl-, pyrenyl- and anthracenyl-fused zinc porphyrin derivatives. To this aim, meso-substitued porphyrins are synthesized and the fusion of the PAHs (Polycyclic Aromatic Hydrocarbon) on the β-positions are performed through thermally induced dehydro-aromatization. The fused zinc-porphyrin derivatives are fully characterized and their optical absorption and photoluminescence properties are reported. We also demonstrate that zinc can be removed from the porphyrin core, giving rise to pure C, H, N materials. This work constitutes the first step towards the synthesis of the fully-fused tetra-anthracenylporphyrin.
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Affiliation(s)
- Joffrey Pijeat
- Université Paris-SaclayCEA, CNRS, NIMBE, LICSEN91191Gif-sur-YvetteFrance
| | - Léo Chaussy
- Université Paris-SaclayCEA, CNRS, NIMBE, LICSEN91191Gif-sur-YvetteFrance
| | - Roxanne Simoës
- Université Paris-SaclayCEA, CNRS, NIMBE, LICSEN91191Gif-sur-YvetteFrance
| | - Jacopo Isopi
- Dipartimento di Chimica “Giacomo Ciamician”Università di Bolognavia Selmi 240126BolognaItaly
| | - Jean‐Sébastien Lauret
- Université Paris SaclayENS Paris-SaclayCentrale Supelec, CNRS, LUMIN91405Orsay CedexFrance
| | - Francesco Paolucci
- Dipartimento di Chimica “Giacomo Ciamician”Università di Bolognavia Selmi 240126BolognaItaly
| | - Massimo Marcaccio
- Dipartimento di Chimica “Giacomo Ciamician”Università di Bolognavia Selmi 240126BolognaItaly
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Wechsler D, Fernández CC, Köbl J, Augustin LM, Stumm C, Jux N, Steinrück HP, Williams FJ, Lytken O. Wet-Chemically Prepared Porphyrin Layers on Rutile TiO 2(110). Molecules 2021; 26:molecules26102871. [PMID: 34066129 PMCID: PMC8150575 DOI: 10.3390/molecules26102871] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 05/07/2021] [Accepted: 05/07/2021] [Indexed: 11/16/2022] Open
Abstract
Porphyrins are large organic molecules that are interesting for different applications, such as photovoltaic cells, gas sensors, or in catalysis. For many of these applications, the interactions between adsorbed molecules and surfaces play a crucial role. Studies of porphyrins on surfaces typically fall into one of two groups: (1) evaporation onto well-defined single-crystal surfaces under well-controlled ultrahigh vacuum conditions or (2) more application-oriented wet chemical deposition onto less well-defined high surface area surfaces under ambient conditions. In this study, we will investigate the wet chemical deposition of 5-(monocarboxyphenyl)-10,15,20-triphenylporphyrin (MCTPP) on well-defined rutile TiO2(110) single crystals under ambient conditions. Prior to deposition, the TiO2(110) crystals were also cleaned wet-chemically under ambient conditions, meaning none of the preparation steps were done in ultrahigh vacuum. However, after each preparation step, the surfaces were characterized in ultrahigh vacuum with X-ray photoelectron spectroscopy (XPS) and the result was compared with porphyrin layers prepared in ultrahigh vacuum (UHV) by evaporation. The differences of both preparations when exposed to zinc ion solutions will also be discussed.
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Affiliation(s)
- Daniel Wechsler
- Lehrstuhl für Physikalische Chemie II, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 3, 91058 Erlangen, Germany; (D.W.); (J.K.); (L.-M.A.); (H.-P.S.)
| | - Cynthia Carolina Fernández
- Departamento de Química Inorgánica, Analítica y Química Física, Facultad de Ciencias Exactas y Naturales, INQUIMAE-CONICET, Universidad de Buenos Aires, Ciudad Universitaria, Pabellón 2, Buenos Aires C1428EHA, Argentina; (C.C.F.); (F.J.W.)
| | - Julia Köbl
- Lehrstuhl für Physikalische Chemie II, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 3, 91058 Erlangen, Germany; (D.W.); (J.K.); (L.-M.A.); (H.-P.S.)
| | - Lisa-Marie Augustin
- Lehrstuhl für Physikalische Chemie II, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 3, 91058 Erlangen, Germany; (D.W.); (J.K.); (L.-M.A.); (H.-P.S.)
| | - Corinna Stumm
- Lehrstuhl für Katalytische Grenzflächenforschung, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 3, 91058 Erlangen, Germany;
| | - Norbert Jux
- Lehrstuhl für Organische Chemie II, Friedrich-Alexander-Universität Erlangen-Nürnberg, Nikolaus-Fiebiger-Str. 10, 91058 Erlangen, Germany;
| | - Hans-Peter Steinrück
- Lehrstuhl für Physikalische Chemie II, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 3, 91058 Erlangen, Germany; (D.W.); (J.K.); (L.-M.A.); (H.-P.S.)
| | - Federico José Williams
- Departamento de Química Inorgánica, Analítica y Química Física, Facultad de Ciencias Exactas y Naturales, INQUIMAE-CONICET, Universidad de Buenos Aires, Ciudad Universitaria, Pabellón 2, Buenos Aires C1428EHA, Argentina; (C.C.F.); (F.J.W.)
| | - Ole Lytken
- Lehrstuhl für Physikalische Chemie II, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstraße 3, 91058 Erlangen, Germany; (D.W.); (J.K.); (L.-M.A.); (H.-P.S.)
- Correspondence:
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4
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Adhikari R, Siglreithmaier G, Gurrath M, Meusel M, Kuliga J, Lepper M, Hölzel H, Jux N, Meyer B, Steinrück H, Marbach H. Formation of Highly Ordered Molecular Porous 2D Networks from Cyano-Functionalized Porphyrins on Cu(111). Chemistry 2020; 26:13408-13418. [PMID: 32573877 PMCID: PMC7692896 DOI: 10.1002/chem.202001980] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Indexed: 12/04/2022]
Abstract
We investigated the adsorption of three related cyano-functionalized tetraphenyl porphyrin derivatives on Cu(111) by scanning tunneling microscopy (STM) in ultra-high vacuum (UHV) with the goal to identify the role of the cyano group and the central Cu atom for the intermolecular and supramolecular arrangement. The porphyrin derivatives studied were Cu-TCNPP, Cu-cisDCNPP, and 2H-cisDCNPP, that is, Cu-5,10,15,20-tetrakis-(p-cyano)-phenylporphyrin, Cu-meso-cis-di(p-cyano)-phenylporphyrin and 2H-meso-cis-di(p-cyano)-phenylporphyrin, respectively. Starting from different structures obtained after deposition at room temperature, all three molecules form the same long-range ordered hexagonal honeycomb-type structure with triangular pores and three molecules per unit cell. For the metal-free 2H-cisDCNPP, this occurs only after self-metalation upon heating. The structure-forming elements are pores with a distance of 3.1 nm, formed by triangles of porphyrins fused together by cyano-Cu-cyano interactions with Cu adatoms. This finding leads us to suggest that two cyano-phenyl groups in the "cis" position is the minimum prerequisite to form a highly ordered 2D porous molecular pattern. The experimental findings are supported by detailed density functional theory calculations to analyze the driving forces that lead to the formation of the porous hexagonal honeycomb-type structure.
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Affiliation(s)
- Rajan Adhikari
- Lehrstuhl für Physikalische Chemie IIFriedrich-Alexander-Universität Erlangen-NürnbergEgerlandstr. 391058ErlangenGermany
| | - Gretel Siglreithmaier
- Lehrstuhl für Physikalische Chemie IIFriedrich-Alexander-Universität Erlangen-NürnbergEgerlandstr. 391058ErlangenGermany
| | - Martin Gurrath
- Interdisciplinary Center for Molecular Materials (ICMM) anComputer-Chemistry-Center (CCC)Friedrich-Alexander-Universität Erlangen-NürnbergNägelsbachstr. 2591052ErlangenGermany
| | - Manuel Meusel
- Lehrstuhl für Physikalische Chemie IIFriedrich-Alexander-Universität Erlangen-NürnbergEgerlandstr. 391058ErlangenGermany
| | - Jan Kuliga
- Lehrstuhl für Physikalische Chemie IIFriedrich-Alexander-Universität Erlangen-NürnbergEgerlandstr. 391058ErlangenGermany
| | - Michael Lepper
- Lehrstuhl für Physikalische Chemie IIFriedrich-Alexander-Universität Erlangen-NürnbergEgerlandstr. 391058ErlangenGermany
| | - Helen Hölzel
- Lehrstuhl für Organische Chemie IIFriedrich-Alexander-Universität Erlangen-NürnbergNikolaus-Fiebiger-Str. 1091058ErlangenGermany
| | - Norbert Jux
- Lehrstuhl für Organische Chemie IIFriedrich-Alexander-Universität Erlangen-NürnbergNikolaus-Fiebiger-Str. 1091058ErlangenGermany
| | - Bernd Meyer
- Interdisciplinary Center for Molecular Materials (ICMM) anComputer-Chemistry-Center (CCC)Friedrich-Alexander-Universität Erlangen-NürnbergNägelsbachstr. 2591052ErlangenGermany
| | - Hans‐Peter Steinrück
- Lehrstuhl für Physikalische Chemie IIFriedrich-Alexander-Universität Erlangen-NürnbergEgerlandstr. 391058ErlangenGermany
| | - Hubertus Marbach
- Lehrstuhl für Physikalische Chemie IIFriedrich-Alexander-Universität Erlangen-NürnbergEgerlandstr. 391058ErlangenGermany
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5
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Kataev E, Wechsler D, Williams FJ, Köbl J, Tsud N, Franchi S, Steinrück H, Lytken O. Probing the Roughness of Porphyrin Thin Films with X-ray Photoelectron Spectroscopy. Chemphyschem 2020; 21:2293-2300. [PMID: 32820833 PMCID: PMC7702074 DOI: 10.1002/cphc.202000568] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 08/06/2020] [Indexed: 11/08/2022]
Abstract
Thin-film growth of molecular systems is of interest for many applications, such as for instance organic electronics. In this study, we demonstrate how X-ray photoelectron spectroscopy (XPS) can be used to study the growth behavior of such molecular systems. In XPS, coverages are often calculated assuming a uniform thickness across a surface. This results in an error for rough films, and the magnitude of this error depends on the kinetic energy of the photoelectrons analyzed. We have used this kinetic-energy dependency to estimate the roughnesses of thin porphyrin films grown on rutile TiO2 (110). We used two different molecules: cobalt (II) monocarboxyphenyl-10,15,20-triphenylporphyrin (CoMCTPP), with carboxylic-acid anchor groups, and cobalt (II) tetraphenylporphyrin (CoTPP), without anchor groups. We find CoMCTPP to grow as rough films at room temperature across the studied coverage range, whereas for CoTPP the first two layers remain smooth and even; depositing additional CoTPP results in rough films. Although, XPS is not a common technique for measuring roughness, it is fast and provides information of both roughness and thickness in one measurement.
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Affiliation(s)
- Elmar Kataev
- Department of Chemistry and PharmacyFriedrich-Alexander Universität Erlangen-NürnbergEgerlandstraße 3Erlangen91058Germany
| | - Daniel Wechsler
- Department of Chemistry and PharmacyFriedrich-Alexander Universität Erlangen-NürnbergEgerlandstraße 3Erlangen91058Germany
| | - Federico J. Williams
- Departamento de Química Inorgánica, Analítica y Química FísicaUniversidad de Buenos AiresPabellón 2Buenos AiresC1428EHAArgentina
| | - Julia Köbl
- Department of Chemistry and PharmacyFriedrich-Alexander Universität Erlangen-NürnbergEgerlandstraße 3Erlangen91058Germany
| | - Natalia Tsud
- Department of Surface and Plasma ScienceCharles UniversityV Holešovičkách 2Prague11636Czech Republic
| | - Stefano Franchi
- Istituto di Struttura della MateriaConsiglio Nazionale delle Ricerchevia Fosso del Cavaliere100RomaItaly
| | - Hans‐Peter Steinrück
- Department of Chemistry and PharmacyFriedrich-Alexander Universität Erlangen-NürnbergEgerlandstraße 3Erlangen91058Germany
| | - Ole Lytken
- Department of Chemistry and PharmacyFriedrich-Alexander Universität Erlangen-NürnbergEgerlandstraße 3Erlangen91058Germany
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6
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Wechsler D, Fernández CC, Tariq Q, Tsud N, Prince KC, Williams FJ, Steinrück HP, Lytken O. Interfacial Reactions of Tetraphenylporphyrin with Cobalt-Oxide Thin Films. Chemistry 2019; 25:13197-13201. [PMID: 31403232 DOI: 10.1002/chem.201902680] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2019] [Revised: 08/08/2019] [Indexed: 11/07/2022]
Abstract
We have studied the adsorption and interfacial reactions of 2H-tetraphenylporphyrin (2HTPP) with cobalt-terminated Co3 O4 (111) and oxygen-terminated CoO(111) thin films using synchrotron-radiation X-ray photoelectron spectroscopy. Already at 275 K, we find evidence for the formation of a metalated species, most likely CoTPP, on both surfaces. The degree of self-metalation increases with temperature on both surfaces until 475 K, where the metalation is almost complete. At 575 K the porphyrin coverage decreases drastically on the reducible cobalt-terminated Co3 O4 (111) surface, while higher temperatures are needed on the non-reducible oxygen-terminated CoO(111). The low temperature self-metalation is similar to that observed on MgO(100) surfaces, but drastically different from that observed on TiO2 (110), where no self-metalation is observed at room temperature.
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Affiliation(s)
- Daniel Wechsler
- Chair of Physical Chemistry II, University Erlangen-Nürnberg, Egerlandstraße 3, 91058, Erlangen, Germany
| | - Cynthia C Fernández
- Departamento de Química Inorgánica, AnalíticayQuímica Física, Facultad de Ciencias ExactasyNaturales, INQUIMAE-CONICET, Universidad de Buenos Aires, Pabellón 2, Buenos Aires, C1428EHA, Argentina
| | - Quratulain Tariq
- Chair of Physical Chemistry II, University Erlangen-Nürnberg, Egerlandstraße 3, 91058, Erlangen, Germany
| | - Nataliya Tsud
- Elettra-Sincrotrone Trieste S.C.p.A., Strada Statale 14, km 163.5, 34149, Basovizza-Trieste, Italy
| | - Kevin C Prince
- Elettra-Sincrotrone Trieste S.C.p.A., Strada Statale 14, km 163.5, 34149, Basovizza-Trieste, Italy.,IOM, Strada Statale 14, km 163.5, 34149, Basovizza-Trieste, Italy
| | - Federico J Williams
- Chair of Physical Chemistry II, University Erlangen-Nürnberg, Egerlandstraße 3, 91058, Erlangen, Germany.,Departamento de Química Inorgánica, AnalíticayQuímica Física, Facultad de Ciencias ExactasyNaturales, INQUIMAE-CONICET, Universidad de Buenos Aires, Pabellón 2, Buenos Aires, C1428EHA, Argentina
| | - Hans-Peter Steinrück
- Chair of Physical Chemistry II, University Erlangen-Nürnberg, Egerlandstraße 3, 91058, Erlangen, Germany
| | - Ole Lytken
- Chair of Physical Chemistry II, University Erlangen-Nürnberg, Egerlandstraße 3, 91058, Erlangen, Germany
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Mairena A, Baljozovic M, Kawecki M, Grenader K, Wienke M, Martin K, Bernard L, Avarvari N, Terfort A, Ernst KH, Wäckerlin C. The fate of bromine after temperature-induced dehydrogenation of on-surface synthesized bisheptahelicene. Chem Sci 2019; 10:2998-3004. [PMID: 30996879 PMCID: PMC6430192 DOI: 10.1039/c8sc04720k] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Accepted: 01/15/2019] [Indexed: 12/18/2022] Open
Abstract
The dehydrogenation of bisheptahelicene leads to specific products and induces desorption of the side-product bromine as hydrogen bromide.
The on-surface synthesis of bisheptahelicene by Ullmann coupling of 9-bromoheptahelicene on Au(111) and its temperature-induced dehydrogenation is studied using temperature-programmed reaction spectroscopy and time-of-flight secondary ion mass spectrometry. Specific dehydrogenation products of bisheptahelicene after loss of 6, 8 and 10 hydrogen atoms are identified, corresponding to molecules having undergone Diels–Alder transformations and intramolecular C–C coupling reactions. By combining with atomic hydrogen produced by dehydrogenation, the Ullmann coupling side-product bromine desorbs as HBr. H2 desorption emerges only after all Br has desorbed. Such characteristic behavior is explained by a kinetic model which explicitly considers the coverage of transient atomic H on the surface. Heating experiments performed with saturated layers of different Br-containing molecules reveal that the onset of HBr desorption depends strictly on the dehydrogenation step and therefore on the structure of the molecules.
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Affiliation(s)
- Anaïs Mairena
- Empa, Swiss Federal Laboratories for Materials Science and Technology , 8600 Dübendorf , Switzerland . ;
| | - Milos Baljozovic
- Empa, Swiss Federal Laboratories for Materials Science and Technology , 8600 Dübendorf , Switzerland . ;
| | - Maciej Kawecki
- Empa, Swiss Federal Laboratories for Materials Science and Technology , 8600 Dübendorf , Switzerland . ;
| | - Konstantin Grenader
- Department of Chemistry , Institute of Inorganic and Analytical Chemistry , Goethe-University , 60438 Frankfurt , Germany
| | - Martin Wienke
- Department of Chemistry , University of Hamburg , 20146 Hamburg , Germany
| | - Kévin Martin
- Laboratoire Moltech-Anjou , CNRS-Université d'Angers , 49045 Angers , France
| | - Laetitia Bernard
- Empa, Swiss Federal Laboratories for Materials Science and Technology , 8600 Dübendorf , Switzerland . ;
| | - Narcis Avarvari
- Laboratoire Moltech-Anjou , CNRS-Université d'Angers , 49045 Angers , France
| | - Andreas Terfort
- Department of Chemistry , Institute of Inorganic and Analytical Chemistry , Goethe-University , 60438 Frankfurt , Germany
| | - Karl-Heinz Ernst
- Empa, Swiss Federal Laboratories for Materials Science and Technology , 8600 Dübendorf , Switzerland . ; .,Department of Chemistry , University of Zurich , 8057 Zurich , Switzerland
| | - Christian Wäckerlin
- Empa, Swiss Federal Laboratories for Materials Science and Technology , 8600 Dübendorf , Switzerland . ;
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Stępień M, Gońka E, Żyła M, Sprutta N. Heterocyclic Nanographenes and Other Polycyclic Heteroaromatic Compounds: Synthetic Routes, Properties, and Applications. Chem Rev 2016; 117:3479-3716. [PMID: 27258218 DOI: 10.1021/acs.chemrev.6b00076] [Citation(s) in RCA: 865] [Impact Index Per Article: 108.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Two-dimensionally extended, polycyclic heteroaromatic molecules (heterocyclic nanographenes) are a highly versatile class of organic materials, applicable as functional chromophores and organic semiconductors. In this Review, we discuss the rich chemistry of large heteroaromatics, focusing on their synthesis, electronic properties, and applications in materials science. This Review summarizes the historical development and current state of the art in this rapidly expanding field of research, which has become one of the key exploration areas of modern heterocyclic chemistry.
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Affiliation(s)
- Marcin Stępień
- Wydział Chemii, Uniwersytet Wrocławski , ul. F. Joliot-Curie 14, 50-383 Wrocław, Poland
| | - Elżbieta Gońka
- Wydział Chemii, Uniwersytet Wrocławski , ul. F. Joliot-Curie 14, 50-383 Wrocław, Poland
| | - Marika Żyła
- Wydział Chemii, Uniwersytet Wrocławski , ul. F. Joliot-Curie 14, 50-383 Wrocław, Poland
| | - Natasza Sprutta
- Wydział Chemii, Uniwersytet Wrocławski , ul. F. Joliot-Curie 14, 50-383 Wrocław, Poland
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9
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Marbach H. Surface-Mediated in Situ Metalation of Porphyrins at the Solid-Vacuum Interface. Acc Chem Res 2015; 48:2649-58. [PMID: 26308682 DOI: 10.1021/acs.accounts.5b00243] [Citation(s) in RCA: 75] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The investigation of porphyrin derivatives at the solid-vacuum interface has become a vivid research field with the prospect to tailor functional molecular architectures and as prototype examples to study the fundamental properties of porphyrin derivatives in regard to their vital role in many natural processes. The functional properties of the porphyrin derivatives are mainly determined by the central metal atom. Thus, the recent exploration of the surface-confined in situ metalation of porphyrins is an important step toward the realization of molecule-based functional devices. The corresponding metalation reaction of free base porphyrin derivatives can be conveniently realized in situ in ultrahigh vacuum by post- or predeposition of metal atoms or directly with substrate atoms in the so-called self-metalation. Moderate heating above room temperature (RT) might be necessary either to realize the transport of the metal to the porphyrin via diffusion or to overcome an activation barrier determined by the redox reaction itself. Surface science techniques like scanning tunneling microscopy (STM), X-ray photoelectron spectroscopy (XPS), and temperature-programmed desorption (TPD) are powerful tools to scrutinize the reaction and give valuable insights into the metalation process. For example, the completed metalation can be reflected in an enhanced apparent height of the corresponding porphyrin in STM or can be evidenced by characteristic changes in the N 1s region in XPS. These signatures allow monitoring of the progress of the metalation, and it was found that the reaction generally proceeds with very high yield. Surface diffusion of the coadsorbed metal atoms mediates the reaction and is crucial for the high yields of the corresponding reactions with pre- and postadsorbed metals. It was also demonstrated that the completed metalation can indeed significantly alter the adsorption behavior and the electronic properties and thus the functionality of the porphyrin molecules. These alterations can be used to monitor the kinetics of a particular porphyrin self-metalation reaction by STM and to estimate the activation barrier for that reaction based on isothermal measurements at different temperatures. Also TPD measurements of the H2 and D2 signals allow for the determination of corresponding activation energies for the metalation of free base porphyrins and their deuterized analogues. Gas phase DFT calculations of the metalation of the "bare" free base porphyrin macrocycle identify intermediate reaction steps with the transfer of the first hydrogen atom to the metal center being the main barrier to overcome. The values from these calculations are in fair agreement with experimentally determined ones. However, TPD based results indicate that exchanges of deuterium and hydrogen between the central nitrogen and the surface occur, which indicate an active role of the surface and challenge the findings from gas phase DFT. The in situ metalation of porphyrins at the solid-vacuum interface is established as a novel and convenient route to tailor functional molecular architectures. With different surface science techniques detailed insights into the surface-mediated metalation reaction were achieved for this class of prototype functional molecules.
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Affiliation(s)
- Hubertus Marbach
- Lehrstuhl für Physikalische
Chemie II, Friedrich-Alexander-Universität Erlangen-Nürnberg, Egerlandstrasse 3, 91058 Erlangen, Germany
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