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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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Jensen IM, Chowdhury S, Hu G, Jensen L, Camden JP, Jenkins DM. Seeking a Au-C stretch on gold nanoparticles with 13C-labeled N-heterocyclic carbenes. Chem Commun (Camb) 2023; 59:14524-14527. [PMID: 37966800 DOI: 10.1039/d3cc04973f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2023]
Abstract
Gold nanoparticles were functionalized with natural abundance and 13C-labeled N-heterocyclic carbenes (NHCs) to investigate the Au-C stretch. A combinatorial approach of surface enhanced Raman spectroscopy (SERS) and density-functional theory (DFT) calculations highlighted vibrational modes significantly impacted by isotopic labeling at the carbene carbon. Critically, no isotopically-impacted stretching mode showed majority Au-C character.
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Affiliation(s)
- Isabel M Jensen
- Department of Chemistry, The University of Tennessee, Knoxville, Tennessee 37996, USA.
| | - Shayanta Chowdhury
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - Gaohe Hu
- Department of Chemistry, The Pennsylvania State University, 104 Chemistry Building, University Park, Pennsylvania 16802, USA
| | - Lasse Jensen
- Department of Chemistry, The Pennsylvania State University, 104 Chemistry Building, University Park, Pennsylvania 16802, USA
| | - Jon P Camden
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - David M Jenkins
- Department of Chemistry, The University of Tennessee, Knoxville, Tennessee 37996, USA.
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Dominique NL, Jensen IM, Kaur G, Kotseos CQ, Boggess WC, Jenkins DM, Camden JP. Giving Gold Wings: Ultrabright and Fragmentation Free Mass Spectrometry Reporters for Barcoding, Bioconjugation Monitoring, and Data Storage. Angew Chem Int Ed Engl 2023; 62:e202219182. [PMID: 36853583 DOI: 10.1002/anie.202219182] [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: 12/27/2022] [Revised: 02/24/2023] [Accepted: 02/27/2023] [Indexed: 03/01/2023]
Abstract
The widespread application of laser desorption/ionization mass spectrometry (LDI-MS) highlights the need for a bright and multiplexable labeling platform. While ligand-capped Au nanoparticles (AuNPs) have emerged as a promising LDI-MS contrast agent, the predominant thiol ligands suffer from low ion yields and extensive fragmentation. In this work, we develop a N-heterocyclic carbene (NHC) ligand platform that enhances AuNP LDI-MS performance. NHC scaffolds are tuned to generate barcoded AuNPs which, when benchmarked against thiol-AuNPs, are bright mass tags and form unfragmented ions in high yield. To illustrate the transformative potential of NHC ligands, the mass tags were employed in three orthogonal applications: monitoring a bioconjugation reaction, performing multiplexed imaging, and storing and reading encoded information. These results demonstrate that NHC-nanoparticle systems are an ideal platform for LDI-MS and greatly broaden the scope of nanoparticle contrast agents.
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Affiliation(s)
- Nathaniel L Dominique
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - Isabel M Jensen
- Department of Chemistry, University of Tennessee, Knoxville, Knoxville, TN, 37996, USA
| | - Gurkiran Kaur
- Department of Chemistry, University of Tennessee, Knoxville, Knoxville, TN, 37996, USA
| | - Chandler Q Kotseos
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - William C Boggess
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, 46556, USA
| | - David M Jenkins
- Department of Chemistry, University of Tennessee, Knoxville, Knoxville, TN, 37996, USA
| | - Jon P Camden
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN, 46556, USA
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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.
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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
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Dominique NL, Chen R, Santos AVB, Strausser SL, Rauch T, Kotseos CQ, Boggess WC, Jensen L, Jenkins DM, Camden JP. Ad aurum: tunable transfer of N-heterocyclic carbene complexes to gold surfaces. Inorg Chem Front 2022. [DOI: 10.1039/d2qi01941h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The exceptional stability of N-heterocyclic carbene (NHC) monolayers on gold surfaces and nanoparticles (AuNPs) is enabling new and diverse applications from catalysis to biomedicine.
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Affiliation(s)
- Nathaniel L. Dominique
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - Ran Chen
- Department of Chemistry, Penn State University, 101 Chemistry Building, University Park, PA 16802, USA
| | - Alyssa V. B. Santos
- Department of Chemistry, Penn State University, 101 Chemistry Building, University Park, PA 16802, USA
| | - Shelby L. Strausser
- Department of Chemistry, University of Tennessee, Knoxville, Knoxville, Tennessee 37996, USA
| | - Theodore Rauch
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - Chandler Q. Kotseos
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - William C. Boggess
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | - Lasse Jensen
- Department of Chemistry, Penn State University, 101 Chemistry Building, University Park, PA 16802, USA
| | - David M. Jenkins
- Department of Chemistry, University of Tennessee, Knoxville, Knoxville, Tennessee 37996, USA
| | - Jon P. Camden
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, Indiana 46556, USA
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