1
|
Zhang T, Khomane SB, Singh I, Crudden CM, McBreen PH. N-heterocyclic carbene adsorption states on Pt(111) and Ru(0001). Phys Chem Chem Phys 2024; 26:4083-4090. [PMID: 38226886 DOI: 10.1039/d3cp03539e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2024]
Abstract
N-heterocyclic carbene ligands (NHCs) are increasingly used to tune the properties of metal surfaces. The generally greater chemical and thermal robustness of NHCs on gold, as compared to thiolate surface ligands, underscores their potential for a range of applications. While much is now known about the adsorption geometry, overlayer structure, dynamics, and stability of NHCs on coinage elements, especially gold and copper, much less is known about their interaction with the surfaces of Pt-group metals, despite the importance of such metals in catalysis and electrochemistry. In this study, reflection absorption infrared spectroscopy (RAIRS) is used to probe the structure of benzimidazolylidene NHC ligands on Pt(111) and Ru(0001). The experiments exploit the intense absorption peaks of a CF3 substituent on the phenyl ring of the NHC backbone to provide unprecedented insight into adsorption geometry and chemical stability. The results also permit comparison with literature data for NHC ligands on Au(111) and to DFT predictions for NHCs on Pt(111) and Ru(0001), thereby greatly extending the known surface chemistry of NHCs and providing much needed molecular information for the design of metal-organic hybrid materials involving strongly reactive metals.
Collapse
Affiliation(s)
- Tianchi Zhang
- Département de chimie et CCVC, Université Laval, Québec (Que), Canada, G1K OA6.
| | - Sonali B Khomane
- Département de chimie et CCVC, Université Laval, Québec (Que), Canada, G1K OA6.
| | - Ishwar Singh
- Department of Chemistry, Queen's University, 90 Bader Lane, Kingston, Ontario, Canada, K7L 3N6.
| | - Cathleen M Crudden
- Department of Chemistry, Queen's University, 90 Bader Lane, Kingston, Ontario, Canada, K7L 3N6.
| | - Peter H McBreen
- Département de chimie et CCVC, Université Laval, Québec (Que), Canada, G1K OA6.
| |
Collapse
|
2
|
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.
Collapse
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
| |
Collapse
|
3
|
Thimes RL, Santos AVB, Chen R, Kaur G, Jensen L, Jenkins DM, Camden JP. Using Surface-Enhanced Raman Spectroscopy to Unravel the Wingtip-Dependent Orientation of N-Heterocyclic Carbenes on Gold Nanoparticles. J Phys Chem Lett 2023; 14:4219-4224. [PMID: 37125787 DOI: 10.1021/acs.jpclett.3c00588] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
N-Heterocyclic carbenes (NHCs) are an attractive alternative to thiol ligands when forming self-assembled monolayers on noble-metal surfaces; however, relative to the well-studied thiol monolayers, comparatively little is known about the binding, orientation, and packing of NHC monolayers. Herein, we combine surface-enhanced Raman spectroscopy (SERS) and first-principles theory to investigate how the alkyl "wingtip" groups, i.e., those attached to the nitrogens of N-heterocyclic carbenes, affect the NHC orientation on gold nanoparticles. Consistent with previous literature, smaller wingtip groups lead to stable flat configurations; surprisingly, bulkier wingtips also have stable flat configurations likely due to the presence of an adatom. Comparison of experimental SERS results with the theoretically calculated spectra for flat and vertical configurations shows that we are simultaneously detecting both NHC configurations. In addition to providing information on the adsorbate geometry, this study highlights the extreme SERS enhancement of vibrational modes perpendicular to the surface.
Collapse
Affiliation(s)
- Rebekah L Thimes
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| | - Alyssa V B Santos
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Ran Chen
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Gurkiran Kaur
- Department of Chemistry, University of Tennessee, Knoxville, Knoxville, Tennessee 37996, United States
| | - Lasse Jensen
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - David M Jenkins
- Department of Chemistry, University of Tennessee, Knoxville, Knoxville, Tennessee 37996, United States
| | - Jon P Camden
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, United States
| |
Collapse
|
4
|
Park S, Kang S, Yoon HJ. Thermopower of Molecular Junction in Harsh Thermal Environments. NANO LETTERS 2022; 22:3953-3960. [PMID: 35575639 DOI: 10.1021/acs.nanolett.2c00422] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Molecular junctions can be miniaturized devices for heat-to-electricity conversion application, yet these operate only in mild thermal environments (less than 323 K) because thiol, the most widely used anchor moiety for chemisorption of active molecules onto surface of electrode, easily undergoes thermal degradation. N-Heterocyclic carbene (NHC) can be an alternative to traditional thiol anchor for producing ultrastable thermoelectric molecular junctions. Our experiments showed that the NHC-based molecular junctions withstood remarkably high temperatures up to 573 K, exhibiting consistent Seebeck effect and thermovoltage up to approximately |1900 μV|. Our work advances our understanding of molecule-electrode contact in the Seebeck effect, providing a roadmap for constructing robust and efficient organic thermoelectric devices.
Collapse
Affiliation(s)
- Sohyun Park
- Department of Chemistry, Korea University, Seoul 02841, Korea
| | - Seohyun Kang
- Department of Chemistry, Korea University, Seoul 02841, Korea
| | - Hyo Jae Yoon
- Department of Chemistry, Korea University, Seoul 02841, Korea
| |
Collapse
|
5
|
Angove E, Grillo F, Früchtl HA, Veinot AJ, Singh I, Horton JH, Crudden CM, Baddeley CJ. Highly Ordered N-Heterocyclic Carbene Monolayers on Cu(111). J Phys Chem Lett 2022; 13:2051-2056. [PMID: 35200016 PMCID: PMC9007529 DOI: 10.1021/acs.jpclett.1c04073] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The benzannulated N-heterocyclic carbene, 1,3-dibenzylbenzimidazolylidene (NHCDBZ) forms large, highly ordered domains when adsorbed on Cu(111) under ultrahigh vacuum conditions. A combination of scanning tunnelling microscopy (STM), high-resolution electron energy loss spectroscopy (HREELS), and density functional theory (DFT) calculations reveals that the overlayer consists of vertical benzannulated NHC moieties coordinating to Cu adatoms. Long-range order results from the placement of the two benzyl substituents on opposite sides of the benzimidazole moiety, with their aromatic rings approximately parallel to the surface. The organization of three surface-bound benzyl substituents from three different NHCs into a triangular array controls the formation of a highly ordered Kagome-like surface lattice. By comparison with earlier studies of NHCs on Cu(111), we show that the binding geometry and self-assembly of NHCDBZ are influenced by intermolecular and adsorbate-substrate interactions and facilitated by the flexibility of the methylene linkage between the N-heterocycle and the aromatic wingtip substituents.
Collapse
Affiliation(s)
- Eloise Angove
- EaStCHEM
School of Chemistry, University of St. Andrews, North Haugh, St Andrews, Fife KY16
9ST, United Kingdom
| | - Federico Grillo
- EaStCHEM
School of Chemistry, University of St. Andrews, North Haugh, St Andrews, Fife KY16
9ST, United Kingdom
| | - Herbert A. Früchtl
- EaStCHEM
School of Chemistry, University of St. Andrews, North Haugh, St Andrews, Fife KY16
9ST, United Kingdom
| | - Alex J. Veinot
- Department
of Chemistry, Queen’s University, 90 Bader Lane, Kingston, Ontario Canada, K7L 3N6
| | - Ishwar Singh
- Department
of Chemistry, Queen’s University, 90 Bader Lane, Kingston, Ontario Canada, K7L 3N6
| | - J. Hugh Horton
- Department
of Chemistry, Queen’s University, 90 Bader Lane, Kingston, Ontario Canada, K7L 3N6
| | - Cathleen M. Crudden
- Department
of Chemistry, Queen’s University, 90 Bader Lane, Kingston, Ontario Canada, K7L 3N6
- Institute
of Transformative Bio-Molecules, ITbM-WPI, Nagoya University, Nagoya, Chikusa 464-8601, Japan
| | - Christopher J. Baddeley
- EaStCHEM
School of Chemistry, University of St. Andrews, North Haugh, St Andrews, Fife KY16
9ST, United Kingdom
| |
Collapse
|
6
|
Kaur G, Thimes RL, Camden JP, Jenkins DM. Fundamentals and applications of N-heterocyclic carbene functionalized gold surfaces and nanoparticles. Chem Commun (Camb) 2022; 58:13188-13197. [DOI: 10.1039/d2cc05183d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Improved stability and higher degree of synthetic tunability has allowed N-heterocyclic carbenes to supplant thiols as ligands for gold surface functionalization. This review article summarizes the basic science and applications of NHCs on gold.
Collapse
Affiliation(s)
- Gurkiran Kaur
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee, 37996, USA
| | - Rebekah L. Thimes
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana, 46556, USA
| | - Jon P. Camden
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana, 46556, USA
| | - David M. Jenkins
- Department of Chemistry, University of Tennessee, Knoxville, Tennessee, 37996, USA
| |
Collapse
|