1
|
Lee W, Li L, Camarasa-Gómez M, Hernangómez-Pérez D, Roy X, Evers F, Inkpen MS, Venkataraman L. Photooxidation driven formation of Fe-Au linked ferrocene-based single-molecule junctions. Nat Commun 2024; 15:1439. [PMID: 38365892 PMCID: PMC10873316 DOI: 10.1038/s41467-024-45707-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Accepted: 02/02/2024] [Indexed: 02/18/2024] Open
Abstract
Metal-metal contacts, though not yet widely realized, may provide exciting opportunities to serve as tunable and functional interfaces in single-molecule devices. One of the simplest components which might facilitate such binding interactions is the ferrocene group. Notably, direct bonds between the ferrocene iron center and metals such as Pd or Co have been demonstrated in molecular complexes comprising coordinating ligands attached to the cyclopentadienyl rings. Here, we demonstrate that ferrocene-based single-molecule devices with Fe-Au interfacial contact geometries form at room temperature in the absence of supporting coordinating ligands. Applying a photoredox reaction, we propose that ferrocene only functions effectively as a contact group when oxidized, binding to gold through a formal Fe3+ center. This observation is further supported by a series of control measurements and density functional theory calculations. Our findings extend the scope of junction contact chemistries beyond those involving main group elements, lay the foundation for light switchable ferrocene-based single-molecule devices, and highlight new potential mechanistic function(s) of unsubstituted ferrocenium groups in synthetic processes.
Collapse
Affiliation(s)
- Woojung Lee
- Department of Chemistry, Columbia University, New York, NY, 10027, USA
| | - Liang Li
- Department of Chemistry, Columbia University, New York, NY, 10027, USA
| | - María Camarasa-Gómez
- Institute of Theoretical Physics, University of Regensburg, 93040, Regensburg, Germany
| | | | - Xavier Roy
- Department of Chemistry, Columbia University, New York, NY, 10027, USA
| | - Ferdinand Evers
- Institute of Theoretical Physics, University of Regensburg, 93040, Regensburg, Germany.
| | - Michael S Inkpen
- Department of Chemistry, University of Southern California, Los Angeles, CA, 90089, USA.
| | - Latha Venkataraman
- Department of Chemistry, Columbia University, New York, NY, 10027, USA.
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, NY, 10027, USA.
| |
Collapse
|
2
|
Camarasa-Gómez M, Hernangómez-Pérez D, Inkpen MS, Lovat G, Fung ED, Roy X, Venkataraman L, Evers F. Mechanically Tunable Quantum Interference in Ferrocene-Based Single-Molecule Junctions. Nano Lett 2020; 20:6381-6386. [PMID: 32787164 DOI: 10.1021/acs.nanolett.0c01956] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Ferrocenes are ubiquitous organometallic building blocks that comprise a Fe atom sandwiched between two cyclopentadienyl (Cp) rings that rotate freely at room temperature. Of widespread interest in fundamental studies and real-world applications, they have also attracted some interest as functional elements of molecular-scale devices. Here we investigate the impact of the configurational degrees of freedom of a ferrocene derivative on its single-molecule junction conductance. Measurements indicate that the conductance of the ferrocene derivative, which is suppressed by 2 orders of magnitude as compared to a fully conjugated analogue, can be modulated by altering the junction configuration. Ab initio transport calculations show that the low conductance is a consequence of destructive quantum interference effects of the Fano type that arise from the hybridization of localized metal-based d-orbitals and the delocalized ligand-based π-system. By rotation of the Cp rings, the hybridization, and thus the quantum interference, can be mechanically controlled, resulting in a conductance modulation that is seen experimentally.
Collapse
Affiliation(s)
- María Camarasa-Gómez
- Institute of Theoretical Physics, University of Regensburg, 93040 Regensburg, Germany
| | - Daniel Hernangómez-Pérez
- Institute of Theoretical Physics, University of Regensburg, 93040 Regensburg, Germany
- Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot 761001, Israel
| | - Michael S Inkpen
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, United States
| | - Giacomo Lovat
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, United States
| | - E-Dean Fung
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, United States
| | - Xavier Roy
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Latha Venkataraman
- Department of Applied Physics and Applied Mathematics, Columbia University, New York, New York 10027, United States
- Department of Chemistry, Columbia University, New York, New York 10027, United States
| | - Ferdinand Evers
- Institute of Theoretical Physics, University of Regensburg, 93040 Regensburg, Germany
| |
Collapse
|
3
|
Fu T, Smith S, Camarasa-Gómez M, Yu X, Xue J, Nuckolls C, Evers F, Venkataraman L, Wei S. Enhanced coupling through π-stacking in imidazole-based molecular junctions. Chem Sci 2019; 10:9998-10002. [PMID: 32055356 PMCID: PMC6979055 DOI: 10.1039/c9sc03760h] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2019] [Accepted: 09/16/2019] [Indexed: 01/12/2023] Open
Abstract
We demonstrate that imidazole based π–π stacked dimers form strong and efficient conductance pathways in single-molecule junctions using the scanning-tunneling microscope-break junction (STM-BJ) technique and density functional theory-based calculations.
We demonstrate that imidazole based π–π stacked dimers form strong and efficient conductance pathways in single-molecule junctions using the scanning-tunneling microscope-break junction (STM-BJ) technique and density functional theory-based calculations. We first characterize an imidazole-gold contact by measuring the conductance of imidazolyl-terminated alkanes (im-N-im, N = 3–6). We show that the conductance of these alkanes decays exponentially with increasing length, indicating that the mechanism for electron transport is through tunneling or super-exchange. We also reveal that π–π stacked dimers can be formed between imidazoles and have better coupling than through-bond tunneling. These experimental results are rationalized by calculations of molecular junction transmission using non-equilibrium Green's function formalism. This study verifies the capability of imidazole as a Au-binding ligand to form stable single- and π-stacked molecule junctions at room temperature.
Collapse
Affiliation(s)
- Tianren Fu
- Department of Chemistry , Columbia University , New York , New York 10027 , USA . ;
| | - Shanelle Smith
- Department of Chemistry , Queensborough Community College of the City University of New York , Bayside , New York 11364 , USA .
| | - María Camarasa-Gómez
- Institute of Theoretical Physics , University of Regensburg , 93040 Regensburg , Germany .
| | - Xiaofang Yu
- Department of Chemistry , Queensborough Community College of the City University of New York , Bayside , New York 11364 , USA .
| | - Jiayi Xue
- Department of Chemistry , Queensborough Community College of the City University of New York , Bayside , New York 11364 , USA . .,Department of Chemistry and Biochemistry , Queens College of the City University of New York , Flushing , New York 11367 , USA
| | - Colin Nuckolls
- Department of Chemistry , Columbia University , New York , New York 10027 , USA . ;
| | - Ferdinand Evers
- Institute of Theoretical Physics , University of Regensburg , 93040 Regensburg , Germany .
| | - Latha Venkataraman
- Department of Chemistry , Columbia University , New York , New York 10027 , USA . ; .,Department of Applied Physics , Columbia University , New York , New York 10027 , USA
| | - Sujun Wei
- Department of Chemistry , Queensborough Community College of the City University of New York , Bayside , New York 11364 , USA .
| |
Collapse
|