1
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Amit E, Mondal R, Berg I, Nairoukh Z, Gross E. N-Heterocyclic Carbene Monolayers on Metal-Oxide Films: Correlations between Adsorption Mode and Surface Functionality. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:10374-10383. [PMID: 38701356 PMCID: PMC11100006 DOI: 10.1021/acs.langmuir.4c01109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Revised: 04/15/2024] [Accepted: 04/19/2024] [Indexed: 05/05/2024]
Abstract
N-Heterocyclic carbene (NHC) ligands have been self-assembled on various metal and semimetal surfaces, creating a covalent bond with surface metal atoms that led to high thermal and chemical stability of the self-assembled monolayer. This study explores the self-assembly of NHCs on metal-oxide films (CuOx, FeOx, and TiOx) and reveals that the properties of these metal-oxide substrates play a pivotal role in dictating the adsorption behavior of NHCs, influencing the decomposition route of the monolayer and its impact on work function values. While the attachment of NHCs onto CuOx is via coordination with surface oxygen atoms, NHCs interact with TiOx through coordination with surface metal atoms and with FeOx via coordination with both metal and oxygen surface atoms. These distinct binding modes arise due to variances in the electronic properties of the metal atoms within the investigated metal-oxide films. Contact angle and ultraviolet photoelectron spectroscopy measurements have shown a significantly higher impact of F-NHC adsorption on CuOx than on TiOx and FeOx , correlated to a preferred, averaged upright orientation of F-NHC on CuOx.
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Affiliation(s)
- Einav Amit
- Institute
of Chemistry, The Hebrew University, Jerusalem 91904, Israel
- The
Center for Nanoscience and Nanotechnology, The Hebrew University, Jerusalem 91904, Israel
| | - Rajarshi Mondal
- Institute
of Chemistry, The Hebrew University, Jerusalem 91904, Israel
| | - Iris Berg
- Institute
of Chemistry, The Hebrew University, Jerusalem 91904, Israel
- The
Center for Nanoscience and Nanotechnology, The Hebrew University, Jerusalem 91904, Israel
| | - Zackaria Nairoukh
- Institute
of Chemistry, The Hebrew University, Jerusalem 91904, Israel
| | - Elad Gross
- Institute
of Chemistry, The Hebrew University, Jerusalem 91904, Israel
- The
Center for Nanoscience and Nanotechnology, The Hebrew University, Jerusalem 91904, Israel
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2
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Ren J, Das M, Osthues H, Nyenhuis M, Schulze Lammers B, Kolodzeiski E, Mönig H, Amirjalayer S, Fuchs H, Doltsinis NL, Glorius F. The Electron-Rich and Nucleophilic N-Heterocyclic Imines on Metal Surfaces: Binding Modes and Interfacial Charge Transfer. J Am Chem Soc 2024; 146:7288-7294. [PMID: 38456796 DOI: 10.1021/jacs.3c11738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2024]
Abstract
The strongly electron-donating N-heterocyclic imines (NHIs) have been employed as excellent surface anchors for the thermodynamic stabilization of electron-deficient species due to their enhanced nucleophilicity. However, the binding mode and interfacial property of these new ligands are still unclear, representing a bottleneck for advanced applications in surface functionalization and catalysis. Here, NHIs with different side groups have been rationally designed, synthesized, and analyzed on various metal surfaces (Cu, Ag). Our results reveal different binding modes depending on the molecular structure and metal surface. The molecular design enables us to achieve a flat-lying or upright configuration and even a transition between these two binding modes depending on the coverage and time. Importantly, the two binding modes exhibit different degrees of interfacial charge transfer between the molecule and the surface. This study provides essential microscopic insight into the NHI adsorption geometry and interfacial charge transfer for the optimization of heterogeneous catalysts in coordination chemistry.
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Affiliation(s)
- Jindong Ren
- CAS Key Laboratory of Nanophotonic Materials and Devices, CAS Key Laboratory of Standardization and Measurement for Nanotechnology, National Center for Nanoscience and Technology, Beijing 100190, P.R. China
- University of Chinese Academy of Sciences, Beijing 100190, P.R. China
| | - Mowpriya Das
- Organisch-Chemisches Institut, Universität Münster, Corrensstraße 40, 48149 Münster, Germany
| | - Helena Osthues
- Institute for Solid State Theory and Center for Multiscale Theory and Computation, Universität Münster, Wilhelm-Klemm-Straße 10, 48149 Münster, Germany
| | - Marvin Nyenhuis
- Institute for Solid State Theory and Center for Multiscale Theory and Computation, Universität Münster, Wilhelm-Klemm-Straße 10, 48149 Münster, Germany
| | - Bertram Schulze Lammers
- Physikalisches Institut, Universität Münster, Wilhelm-Klemm-Straße 10, 48149 Münster, Germany
- Center for Nanotechnology, Heisenbergstraße 11, 48149 Münster, Germany
| | - Elena Kolodzeiski
- Physikalisches Institut, Universität Münster, Wilhelm-Klemm-Straße 10, 48149 Münster, Germany
- Center for Nanotechnology, Heisenbergstraße 11, 48149 Münster, Germany
| | - Harry Mönig
- Physikalisches Institut, Universität Münster, Wilhelm-Klemm-Straße 10, 48149 Münster, Germany
- Center for Nanotechnology, Heisenbergstraße 11, 48149 Münster, Germany
| | - Saeed Amirjalayer
- Institute for Solid State Theory and Center for Multiscale Theory and Computation, Universität Münster, Wilhelm-Klemm-Straße 10, 48149 Münster, Germany
| | - Harald Fuchs
- Physikalisches Institut, Universität Münster, Wilhelm-Klemm-Straße 10, 48149 Münster, Germany
- Center for Nanotechnology, Heisenbergstraße 11, 48149 Münster, Germany
| | - Nikos L Doltsinis
- Institute for Solid State Theory and Center for Multiscale Theory and Computation, Universität Münster, Wilhelm-Klemm-Straße 10, 48149 Münster, Germany
| | - Frank Glorius
- Organisch-Chemisches Institut, Universität Münster, Corrensstraße 40, 48149 Münster, Germany
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3
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Amit E, Berg I, Zhang W, Mondal R, Shema H, Gutkin V, Kravchuk T, Toste FD, Nairoukh Z, Gross E. Selective Deposition of N-Heterocyclic Carbene Monolayers on Designated Au Microelectrodes within an Electrode Array. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024; 20:e2302317. [PMID: 37667447 DOI: 10.1002/smll.202302317] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 08/23/2023] [Indexed: 09/06/2023]
Abstract
The incorporation of organic self-assembled monolayers (SAMs) in microelectronic devices requires precise spatial control over the self-assembly process. In this work, selective deposition of N-heterocyclic carbenes (NHCs) on specific electrodes within a two-microelectrode array is achieved by using pulsed electrodeposition. Spectroscopic analysis of the NHC-coated electrode arrays reveals that each electrode is selectively coated with a designated NHC. The impact of NHC monolayers on the electrodes' work function is quantified using Kelvin probe force microscopy. These measurements demonstrate that the work function values of each electrode can be independently tuned by the adsorption of a specific NHC. The presented deposition method enables to selectively coat designated microelectrodes in an electrode array with chosen NHC monolayers for tuning their chemical and electronic functionality.
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Affiliation(s)
- Einav Amit
- Institute of Chemistry, The Hebrew University, Jerusalem, 9190401, Israel
- The Center for Nanoscience and Nanotechnology, The Hebrew University, Jerusalem, 9190401, Israel
| | - Iris Berg
- Institute of Chemistry, The Hebrew University, Jerusalem, 9190401, Israel
- The Center for Nanoscience and Nanotechnology, The Hebrew University, Jerusalem, 9190401, Israel
| | - Wenhao Zhang
- Department of Chemistry, University of California, Berkeley, CA, 94720, USA
| | - Rajarshi Mondal
- Institute of Chemistry, The Hebrew University, Jerusalem, 9190401, Israel
| | - Hadar Shema
- Institute of Chemistry, The Hebrew University, Jerusalem, 9190401, Israel
- The Center for Nanoscience and Nanotechnology, The Hebrew University, Jerusalem, 9190401, Israel
| | - Vitaly Gutkin
- The Center for Nanoscience and Nanotechnology, The Hebrew University, Jerusalem, 9190401, Israel
| | - Tatyana Kravchuk
- Surface Science Laboratory of Solid-State Institute, Technion - Israel Institute of Technology, Haifa, 3200003, Israel
| | - F Dean Toste
- Department of Chemistry, University of California, Berkeley, CA, 94720, USA
| | - Zackaria Nairoukh
- Institute of Chemistry, The Hebrew University, Jerusalem, 9190401, Israel
| | - Elad Gross
- Institute of Chemistry, The Hebrew University, Jerusalem, 9190401, Israel
- The Center for Nanoscience and Nanotechnology, The Hebrew University, Jerusalem, 9190401, Israel
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4
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Dominique NL, Chandran A, Jensen IM, Jenkins DM, Camden JP. Unmasking the Electrochemical Stability of N-Heterocyclic Carbene Monolayers on Gold. Chemistry 2023:e202303681. [PMID: 38116819 DOI: 10.1002/chem.202303681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Accepted: 12/16/2023] [Indexed: 12/21/2023]
Abstract
N-heterocyclic carbene (NHC) monolayers are transforming electrocatalysis and biosensor design via their increased performance and stability. Despite their increasing use in electrochemical systems, the integrity of the NHC monolayer during voltage perturbations remains largely unknown. Herein, we deploy surface-enhanced Raman spectroscopy (SERS) to measure the stability of two model NHCs on gold in ambient conditions as a function of applied potential and under continuous voltammetric interrogation. Our results illustrate that NHC monolayers exhibit electrochemical stability over a wide voltage window (-1 V to 0.5 V vs Ag|AgCl), but they are found to degrade at strongly reducing (< -1 V) or oxidizing (>0.5 V) potentials. We also address NHC monolayer stability under continuous voltammetric interrogation between 0.2 V and -0.5 V, a commonly used voltage window for sensing, showing they are stable for up to 43 hours. However, we additionally find that modifications of the backbone NHC structure can lead to significantly shorter operational lifetimes. While these results highlight the potential of NHC architectures for electrode functionalization, they also reveal potential pitfalls that have not been fully appreciated in electrochemical applications of NHCs.
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Affiliation(s)
- Nathaniel L Dominique
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN-46556, United States
| | - Aruna Chandran
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN-46556, United States
| | - Isabel M Jensen
- Department of Chemistry, University of Tennessee, Knoxville, Knoxville, TN-37996
| | - David M Jenkins
- Department of Chemistry, University of Tennessee, Knoxville, Knoxville, TN-37996
| | - Jon P Camden
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN-46556, United States
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5
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Das M, Hogan C, Zielinski R, Kubicki M, Koy M, Kosbab C, Brozzesi S, Das A, Nehring MT, Balfanz V, Brühne J, Dähne M, Franz M, Esser N, Glorius F. N-Heterocyclic Olefins on a Silicon Surface. Angew Chem Int Ed Engl 2023; 62:e202314663. [PMID: 37849449 DOI: 10.1002/anie.202314663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 10/13/2023] [Accepted: 10/17/2023] [Indexed: 10/19/2023]
Abstract
The adsorption of N-heterocyclic olefins (NHOs) on silicon is investigated in a combined scanning tunneling microscopy, X-ray photoelectron spectroscopy, and density functional theory study. We find that both of the studied NHOs bind covalently, with ylidic character, to the silicon adatoms of the substrate and exhibit good thermal stability. The adsorption geometry strongly depends on the N-substituents: for large N-substituents, an upright adsorption geometry is favored, while a flat-lying geometry is found for the NHO with smaller wingtips. These different geometries strongly influence the quality and properties of the obtained monolayers. The upright geometry leads to the formation of ordered monolayers, whereas the flat-lying NHOs yield a mostly disordered, but denser, monolayer. The obtained monolayers both show large work function reductions, as the higher density of the flat-lying monolayer is found to compensate for the smaller vertical dipole moments. Our findings offer new prospects in the design of tailor-made ligand structures in organic electronics and optoelectronics, catalysis, and material science.
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Affiliation(s)
- Mowpriya Das
- Westfälische Wilhelms-Universität Münster, Organisch-Chemisches Institut, Corrensstrasse 40, 48149, Münster, Germany
| | - Conor Hogan
- Istituto di Struttura della Materia-CNR (ISM-CNR), Via del Fosso del Cavaliere 100, 00133, Rome, Italy
- Dipartimento di Fisica, Università di Roma 'Tor Vergata', Via della Ricerca Scientifica 1, 00133, Rome, Italy
| | - Robert Zielinski
- Technische Universität Berlin, Institut für Festkörperphysik, Hardenbergstrasse 36, D-10623, Berlin, Germany
| | - Milan Kubicki
- Technische Universität Berlin, Institut für Festkörperphysik, Hardenbergstrasse 36, D-10623, Berlin, Germany
| | - Maximilian Koy
- Westfälische Wilhelms-Universität Münster, Organisch-Chemisches Institut, Corrensstrasse 40, 48149, Münster, Germany
| | - Canan Kosbab
- Technische Universität Berlin, Institut für Festkörperphysik, Hardenbergstrasse 36, D-10623, Berlin, Germany
| | - Simone Brozzesi
- Dipartimento di Fisica, Università di Roma 'Tor Vergata', Via della Ricerca Scientifica 1, 00133, Rome, Italy
| | - Ankita Das
- Westfälische Wilhelms-Universität Münster, Organisch-Chemisches Institut, Corrensstrasse 40, 48149, Münster, Germany
| | - Mike Thomas Nehring
- Technische Universität Berlin, Institut für Festkörperphysik, Hardenbergstrasse 36, D-10623, Berlin, Germany
| | - Viktoria Balfanz
- Technische Universität Berlin, Institut für Festkörperphysik, Hardenbergstrasse 36, D-10623, Berlin, Germany
| | - Juls Brühne
- Technische Universität Berlin, Institut für Festkörperphysik, Hardenbergstrasse 36, D-10623, Berlin, Germany
| | - Mario Dähne
- Technische Universität Berlin, Institut für Festkörperphysik, Hardenbergstrasse 36, D-10623, Berlin, Germany
| | - Martin Franz
- Technische Universität Berlin, Institut für Festkörperphysik, Hardenbergstrasse 36, D-10623, Berlin, Germany
| | - Norbert Esser
- Technische Universität Berlin, Institut für Festkörperphysik, Hardenbergstrasse 36, D-10623, Berlin, Germany
- Leibniz-Institut für Analytische Wissenschaften - ISAS e.V., Schwarzschildstrasse 8, 12489, Berlin, Germany
| | - Frank Glorius
- Westfälische Wilhelms-Universität Münster, Organisch-Chemisches Institut, Corrensstrasse 40, 48149, Münster, Germany
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6
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Berg I, Schio L, Reitz J, Molteni E, Lahav L, Bolaños CG, Goldoni A, Grazioli C, Fratesi G, Hansmann MM, Floreano L, Gross E. Self-Assembled Monolayers of N-Heterocyclic Olefins on Au(111). Angew Chem Int Ed Engl 2023; 62:e202311832. [PMID: 37743324 DOI: 10.1002/anie.202311832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Revised: 09/07/2023] [Accepted: 09/22/2023] [Indexed: 09/26/2023]
Abstract
Self-assembled monolayers (SAMs) of N-heterocyclic olefins (NHOs) have been prepared on Au(111) and their thermal stability, adsorption geometry, and molecular order were characterized by X-ray photoelectron spectroscopy, polarized X-ray absorption spectroscopy, scanning tunneling microscopy (STM), and density functional theory (DFT) calculations. The strong σ-bond character of NHO anchoring to Au induced high geometrical flexibility that enabled a flat-lying adsorption geometry via coordination to a gold adatom. The flat-lying adsorption geometry was utilized to further increase the surface interaction of the NHO monolayer by backbone functionalization with methyl groups that induced high thermal stability and a large impact on work-function values, which outperformed that of N-heterocyclic carbenes. STM measurements, supported by DFT modeling, identified that the NHOs were self-assembled in dimers, trimers, and tetramers constructed of two, three, and four complexes of NHO-Au-adatom. This self-assembly pattern was correlated to strong NHO-Au interactions and steric hindrance between adsorbates, demonstrating the crucial influence of the carbon-metal σ-bond on monolayer properties.
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Affiliation(s)
- Iris Berg
- Institute of Chemistry and The Center for Nanoscience and Nanotechnology, The Hebrew University, Jerusalem, 91904, Israel
| | - Luca Schio
- CNR-IOM, Laboratorio TASC, Basovizza SS-14, Km 163.5, Trieste, 34012, Italy
| | - Justus Reitz
- Technische Universität Dortmund, Fakultät für Chemie und Chemische Biologie, Otto-Hahn-Str. 6, 44227, Dortmund, Germany
| | - Elena Molteni
- Dipartimento di Fisica "Aldo Pontremoli'' Università degli Studi di Milano, Via Celoria 16, 20133, Milano, Italy
| | - Linoy Lahav
- Institute of Chemistry and The Center for Nanoscience and Nanotechnology, The Hebrew University, Jerusalem, 91904, Israel
| | | | - Andrea Goldoni
- Elettra-Sincrotrone Trieste S.C.p.A, Basovizza SS-14, Km 163.5, Trieste, 34149, Italy
| | - Cesare Grazioli
- CNR-IOM, Laboratorio TASC, Basovizza SS-14, Km 163.5, Trieste, 34012, Italy
| | - Guido Fratesi
- Dipartimento di Fisica "Aldo Pontremoli'' Università degli Studi di Milano, Via Celoria 16, 20133, Milano, Italy
| | - Max M Hansmann
- Technische Universität Dortmund, Fakultät für Chemie und Chemische Biologie, Otto-Hahn-Str. 6, 44227, Dortmund, Germany
| | - Luca Floreano
- CNR-IOM, Laboratorio TASC, Basovizza SS-14, Km 163.5, Trieste, 34012, Italy
| | - Elad Gross
- Institute of Chemistry and The Center for Nanoscience and Nanotechnology, The Hebrew University, Jerusalem, 91904, Israel
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7
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Richstein R, Eisen C, Ge L, Chalermnon M, Mayer F, Keppler BK, Chin JM, Reithofer MR. NHC stabilized copper nanoparticles via reduction of a copper NHC complex. Chem Commun (Camb) 2023; 59:9738-9741. [PMID: 37477599 PMCID: PMC10408246 DOI: 10.1039/d3cc02745g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Accepted: 07/11/2023] [Indexed: 07/22/2023]
Abstract
The bottom-up synthesis of plasmonic NHC@CuNPs from common starting reagents, via the formation of the synthetically accessible NHC-Cu(I)-Br complex and its reduction by NH3·BH3 is reported. The resulting NHC@CuNPs have been characterized in detail by XPS, TEM and NMR spectroscopy. The stability of NHC@CuNPs was investigated under both inert and ambient conditions using UV-Vis analysis. While the NHC@CuNPs are stable under inert conditions for an extended period of time, the NPs oxidize under air to form CuxO with concomitant release of the stabilizing NHC ligand.
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Affiliation(s)
- Robert Richstein
- Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Währinger Straße 42, Vienna 1090, Austria.
| | - Constantin Eisen
- Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Währinger Straße 42, Vienna 1090, Austria.
| | - Lingcong Ge
- Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Währinger Straße 42, Vienna 1090, Austria.
| | - Monnaya Chalermnon
- Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Währinger Straße 42, Vienna 1090, Austria.
| | - Florian Mayer
- Institute of Materials Chemistry and Research, Faculty of Chemistry, University of Vienna, Währinger Straße 42, Vienna 1090, Austria
| | - Bernhard K Keppler
- Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Währinger Straße 42, Vienna 1090, Austria.
| | - Jia Min Chin
- Institute of Inorganic Chemistry - Functional Materials, University of Vienna, Währinger Straße 42, Vienna 1090, Austria.
| | - Michael R Reithofer
- Institute of Inorganic Chemistry, Faculty of Chemistry, University of Vienna, Währinger Straße 42, Vienna 1090, Austria.
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8
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Ikemoto S, Muratsugu S, Koitaya T, Tsuji Y, Das M, Yoshizawa K, Glorius F, Tada M. Coordination-Induced Trigger for Activity: N-Heterocyclic Carbene-Decorated Ceria Catalysts Incorporating Cr and Rh with Activity Induction by Surface Adsorption Site Control. J Am Chem Soc 2023; 145:1497-1504. [PMID: 36511728 DOI: 10.1021/jacs.2c07290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
A coordination-induced trigger for catalytic activity is proposed on an N-heterocyclic carbene (NHC)-decorated ceria catalyst incorporating Cr and Rh (ICy-r-Cr0.19Rh0.06CeOz). ICy-r-Cr0.19Rh0.06CeOz was prepared by grafting 1,3-dicyclohexylimidazol-2-ylidene (ICy) onto H2-reduced Cr0.19Rh0.06CeOz (r-Cr0.19Rh0.06CeOz) surfaces, which went on to exhibit substantial catalytic activity for the 1,4-arylation of cyclohexenone with phenylboronic acid, whereas r-Cr0.19Rh0.06CeOz without ICy was inactive. FT-IR, Rh K-edge XAFS, XPS, and photoluminescence spectroscopy showed that the ICy carbene-coordinated Rh nanoclusters were the key active species. The coordination-induced trigger for catalytic activity on the ICy-bearing Rh nanoclusters could not be attributed to electronic donation from ICy to the Rh nanoclusters. DFT calculations suggested that ICy controlled the adsorption sites of the phenyl group on the Rh nanocluster to promote the C-C bond formation of the phenyl group and cyclohexenone.
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Affiliation(s)
- Satoru Ikemoto
- Department of Chemistry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan
| | - Satoshi Muratsugu
- Department of Chemistry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan
| | - Takanori Koitaya
- Department of Materials Molecular Science, Institute for Molecular Science, Myodaiji-cho, Okazaki, Aichi 444-8585, Japan
| | - Yuta Tsuji
- Institute for Materials Chemistry and Engineering and International Research Center for Molecular Systems, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan.,Faculty of Engineering Sciences, Kyushu University, 6-1 Kasuga-koen, Kasuga, Fukuoka 816-8580, Japan
| | - Mowpriya Das
- Westfälische Wilhelms-Universität Münster, Organisch-Chemisches Institut, Corrensstrasse 40, 48149 Münster, Germany
| | - Kazunari Yoshizawa
- Institute for Materials Chemistry and Engineering and International Research Center for Molecular Systems, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Frank Glorius
- Westfälische Wilhelms-Universität Münster, Organisch-Chemisches Institut, Corrensstrasse 40, 48149 Münster, Germany
| | - Mizuki Tada
- Department of Chemistry, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan.,Research Center for Materials Science (RCMS), Integrated Research Consortium on Chemical Sciences (IRCCS), and Institute for Advanced Study, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan
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9
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Choi Y, Park CS, Tran HV, Li CH, Crudden CM, Lee TR. Functionalized N-Heterocyclic Carbene Monolayers on Gold for Surface-Initiated Polymerizations. ACS APPLIED MATERIALS & INTERFACES 2022; 14:44969-44980. [PMID: 36150129 DOI: 10.1021/acsami.2c10985] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
Although N-heterocyclic carbenes (NHCs) are superior to thiol adsorbates in that they form remarkably stable bonds with gold, the generation of NHC-based self-assembled monolayers (SAMs) typically requires a strong base and an inert atmosphere, which limits the utility of such films in many applications. Herein, we report the development and use of bench-stable NHC adsorbates, benzimidazolium methanesulfonates, for the direct formation of NHC films on gold surfaces under an ambient atmosphere at room temperature without the need for extraordinary precautions. The generated NHC SAMs were fully characterized using ellipsometry, X-ray photoelectron spectroscopy (XPS), polarization modulation infrared reflection-absorption spectroscopy (PM-IRRAS), and contact angle measurements, and they were compared to analogous SAMs generated from an NHC bicarbonate adsorbate. Based on these findings, a unique radical initiator α,ω-bidentate azo-terminated NHC adsorbate, NHC15AZO[OMs], was designed and synthesized for the preparation of SAMs on gold surfaces with both NHC headgroups bound to the surface. The adsorbate molecules in NHC15AZO SAMs can exist in a hairpin or a linear conformation depending on the concentration of the adsorbate solution used to prepare the SAM. These conformations were studied by a combination of ellipsometry, XPS, PM-IRRAS, and scanning electron microscopy using gold nanoparticles (AuNPs) as a tag material. Moreover, the potential utility of these unique radical-initiating NHC films as surface-initiated polymerization platforms was demonstrated by controlling the thickness of polystyrene brush films grown from azo-terminated NHC monolayer surfaces simply by adjusting the reaction time of the photoinitiated radical polymer growth process.
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Affiliation(s)
- Yunsoo Choi
- Department of Chemistry and the Texas Center for Superconductivity, University of Houston, 4800 Calhoun Road, Houston, Texas 77204-5003, United States
| | - Chul Soon Park
- Department of Chemistry and the Texas Center for Superconductivity, University of Houston, 4800 Calhoun Road, Houston, Texas 77204-5003, United States
| | - Hung-Vu Tran
- Department of Chemistry and the Texas Center for Superconductivity, University of Houston, 4800 Calhoun Road, Houston, Texas 77204-5003, United States
| | - Chien-Hung Li
- Department of Medicinal and Applied Chemistry, Kaohsiung Medical University, Kaohsiung 807, Taiwan
| | - Cathleen M Crudden
- Department of Chemistry, Queen's University, Kingston, Ontario K7L 3N6, Canada
| | - T Randall Lee
- Department of Chemistry and the Texas Center for Superconductivity, University of Houston, 4800 Calhoun Road, Houston, Texas 77204-5003, United States
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10
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Navarro JJ, Das M, Tosoni S, Landwehr F, Bruce JP, Heyde M, Pacchioni G, Glorius F, Roldan Cuenya B. Covalent Adsorption of N-Heterocyclic Carbenes on a Copper Oxide Surface. J Am Chem Soc 2022; 144:16267-16271. [PMID: 36049156 PMCID: PMC9479068 DOI: 10.1021/jacs.2c06335] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
![]()
Tuning the properties of oxide surfaces through the adsorption
of designed ligands is highly desirable for several applications,
such as catalysis. N-Heterocyclic carbenes (NHCs) have been successfully
employed as ligands for the modification of metallic surfaces. On
the other hand, their potential as modifiers of ubiquitous oxide surfaces
still needs to be developed. Here we show that a model NHC binds covalently
to a copper oxide surface under UHV conditions. In particular, we
report the first example of a covalent bond between NHCs and oxygen
atoms from the oxide layer. This study demonstrates that NHC can also
act as a strong anchor on oxide surfaces.
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Affiliation(s)
- Juan J Navarro
- Department of Interface Science, Fritz-Haber Institute of the Max-Planck Society, 14195 Berlin, Germany
| | - Mowpriya Das
- Westfälische Wilhelms-Universität Münster, Organisch-Chemisches Institut, 48149 Münster, Germany
| | - Sergio Tosoni
- Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, Via Cozzi 55, 20125 Milano, Italy
| | - Felix Landwehr
- Department of Interface Science, Fritz-Haber Institute of the Max-Planck Society, 14195 Berlin, Germany
| | - Jared P Bruce
- Department of Interface Science, Fritz-Haber Institute of the Max-Planck Society, 14195 Berlin, Germany
| | - Markus Heyde
- Department of Interface Science, Fritz-Haber Institute of the Max-Planck Society, 14195 Berlin, Germany
| | - Gianfranco Pacchioni
- Dipartimento di Scienza dei Materiali, Università di Milano-Bicocca, Via Cozzi 55, 20125 Milano, Italy
| | - Frank Glorius
- Westfälische Wilhelms-Universität Münster, Organisch-Chemisches Institut, 48149 Münster, Germany
| | - Beatriz Roldan Cuenya
- Department of Interface Science, Fritz-Haber Institute of the Max-Planck Society, 14195 Berlin, Germany
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