N-heterocyclic carbenes on metal surfaces - towards applications in corrosion inhibition and catalysis
Lead Research Organisation:
University of St Andrews
Department Name: Chemistry
Abstract
This proposal aims to examine the utility of N-heterocyclic carbenes (NHCs) in a number of technologically important areas including corrosion inhibition, etching of metal surfaces and enantioselective heterogeneous catalysis. This is a collaborative project between a catalytic surface scientist (Prof. Chris Baddeley, St Andrews) and experts in organometallic chemistry and materials science (Prof. Cathy Crudden, Queen's University, Ontario) and surface and materials chemistry (Prof. Hugh Horton, Queen's University, Ontario).
NHCs are an exciting class of molecules that have been successfully and extensively employed in homogeneous catalysis since the 1990s. There has recently been a rapid increase in interest in the use of NHCs for the stabilisation of transition metal nanoparticles and extended metal surfaces.
A very attractive feature of NHCs is their highly flexible synthesis. This makes it relatively straightforward to introduce functionality into the molecular structure of NHCs in order to tailor their properties.
A key advance in this area was the development by Crudden's group of synthetic methods to produce bench stable NHCs in the carbonate form. Our work showed that NHCs of this type could be vapour deposited in ultrahigh vacuum onto metal surfaces (Baddeley) as well as being deposited from solution (Horton). Since the 1980s the creation of self-assembled monolayers (SAMs) on metal surfaces has led to many important applications. Commonly, SAMs consist of thiolate modified Au surfaces. Crudden and Horton showed that NHCs on Au outperform their thiolate analogues in terms of chemical and thermal stability. Baddeley was able to measure the strength of the Au-carbene bond and show that it is significantly stronger than the Au-S bond in thiolate SAMs.
This project aims to exploit the chemical and thermal stability of NHC modified metals in a number of ways. Baddeley will use the complementary techniques of scanning tunnelling microscopy, high resolution electron energy loss spectroscopy and temperature programmed desorption to quantify the adsorption energy of NHCs on metal surfaces, to characterise the orientation, packing and thermal stability of adsorbed NHC molecules. The ability of NHCs to etch oxide surfaces and to passivate metal surfaces will be investigated with the objective of applying NHCs in the field of corrosion inhibition. The adsorption of chiral NHCs onto metal surfaces will be investigated with the aim of developing enantioselective heterogeneous catalysts - i.e. catalysts capable of producing one mirror image form of an organic molecule and not the other. Enantioselective catalysis is extremely important in the pharmaceutical and agrochemicals industries, but, to date, heterogeneous catalysts have made little impact on an industrial scale.
NHCs are an exciting class of molecules that have been successfully and extensively employed in homogeneous catalysis since the 1990s. There has recently been a rapid increase in interest in the use of NHCs for the stabilisation of transition metal nanoparticles and extended metal surfaces.
A very attractive feature of NHCs is their highly flexible synthesis. This makes it relatively straightforward to introduce functionality into the molecular structure of NHCs in order to tailor their properties.
A key advance in this area was the development by Crudden's group of synthetic methods to produce bench stable NHCs in the carbonate form. Our work showed that NHCs of this type could be vapour deposited in ultrahigh vacuum onto metal surfaces (Baddeley) as well as being deposited from solution (Horton). Since the 1980s the creation of self-assembled monolayers (SAMs) on metal surfaces has led to many important applications. Commonly, SAMs consist of thiolate modified Au surfaces. Crudden and Horton showed that NHCs on Au outperform their thiolate analogues in terms of chemical and thermal stability. Baddeley was able to measure the strength of the Au-carbene bond and show that it is significantly stronger than the Au-S bond in thiolate SAMs.
This project aims to exploit the chemical and thermal stability of NHC modified metals in a number of ways. Baddeley will use the complementary techniques of scanning tunnelling microscopy, high resolution electron energy loss spectroscopy and temperature programmed desorption to quantify the adsorption energy of NHCs on metal surfaces, to characterise the orientation, packing and thermal stability of adsorbed NHC molecules. The ability of NHCs to etch oxide surfaces and to passivate metal surfaces will be investigated with the objective of applying NHCs in the field of corrosion inhibition. The adsorption of chiral NHCs onto metal surfaces will be investigated with the aim of developing enantioselective heterogeneous catalysts - i.e. catalysts capable of producing one mirror image form of an organic molecule and not the other. Enantioselective catalysis is extremely important in the pharmaceutical and agrochemicals industries, but, to date, heterogeneous catalysts have made little impact on an industrial scale.
Planned Impact
This proposal seeks to functionalise metallic surfaces with N-heterocyclic carbenes in order to create systems that can be exploited in a range of technological applications including enantioselective heterogeneous catalysis, corrosion inhibition and development of new functional materials for application in Surface Plasmon Resonance (SPR).
Economy, Society and Environment:
Tackling corrosion is important in many areas. The development of corrosion inhibitors for Cu based microelectronic devices will impact in the electronics industry and a greater understanding of the mechanism of corrosion inhibition could impact in other areas where Cu corrosion is a significant problem (e.g. industrial cooling systems).
Producing highly stable NHC coated Ag surfaces will facilitate the development of more robust instrumentation for the technique of SPR which currently has a number of biotechnological applications including the development of new pharmaceuticals and in characterising protein function and disease mechanisms. The ability to use NHCs to etch oxide surfaces to create high quality metallic surfaces would benefit companies interested in growing low defect graphene films.
The delivery of highly selective catalytic processes will have enormous impact across the UK chemical industry in a 10-50 year time-frame. The commercial sector face economic pressures including escalating disposal charges and increasing raw material/energy costs, which can be addressed by improved process selectivity. The production of enantiomerically pure compounds via enantioselective catalysis is increasingly important in the pharmaceutical industry. In addition, there is a growing demand for chiral products in the agrochemicals, flavours and fragrances sectors. Heterogeneous enantioselective catalysts are essentially unused in these sectors despite the many potential advantages of heterogeneous systems over their homogeneous counterparts including ease of separation of products from the catalyst. Therefore, the development of new enantioselective heterogeneous catalysts would be of considerable benefit in these industries.
This project will strengthen UK leadership in this field, providing significant employment and wealth creation.
Scientist Training:
The PhD student associated with this project will gain expertise in a range of analytical techniques. The project will develop the leadership skills of the PDRA. Industry and/or academia will benefit via the provision of highly skilled individuals with unique technical and commercial skills that can contribute directly to the chemical sector as effective sustainability practitioners. The sharing of ideas between the groups based in Canada and Baddeley's group in St Andrews will enhance the activities of each research group.
Economy, Society and Environment:
Tackling corrosion is important in many areas. The development of corrosion inhibitors for Cu based microelectronic devices will impact in the electronics industry and a greater understanding of the mechanism of corrosion inhibition could impact in other areas where Cu corrosion is a significant problem (e.g. industrial cooling systems).
Producing highly stable NHC coated Ag surfaces will facilitate the development of more robust instrumentation for the technique of SPR which currently has a number of biotechnological applications including the development of new pharmaceuticals and in characterising protein function and disease mechanisms. The ability to use NHCs to etch oxide surfaces to create high quality metallic surfaces would benefit companies interested in growing low defect graphene films.
The delivery of highly selective catalytic processes will have enormous impact across the UK chemical industry in a 10-50 year time-frame. The commercial sector face economic pressures including escalating disposal charges and increasing raw material/energy costs, which can be addressed by improved process selectivity. The production of enantiomerically pure compounds via enantioselective catalysis is increasingly important in the pharmaceutical industry. In addition, there is a growing demand for chiral products in the agrochemicals, flavours and fragrances sectors. Heterogeneous enantioselective catalysts are essentially unused in these sectors despite the many potential advantages of heterogeneous systems over their homogeneous counterparts including ease of separation of products from the catalyst. Therefore, the development of new enantioselective heterogeneous catalysts would be of considerable benefit in these industries.
This project will strengthen UK leadership in this field, providing significant employment and wealth creation.
Scientist Training:
The PhD student associated with this project will gain expertise in a range of analytical techniques. The project will develop the leadership skills of the PDRA. Industry and/or academia will benefit via the provision of highly skilled individuals with unique technical and commercial skills that can contribute directly to the chemical sector as effective sustainability practitioners. The sharing of ideas between the groups based in Canada and Baddeley's group in St Andrews will enhance the activities of each research group.
Publications
Veinot AJ
(2020)
N-Heterocyclic Carbenes Reduce and Functionalize Copper Oxide Surfaces in One Pot.
in Chemistry (Weinheim an der Bergstrasse, Germany)
Turano M
(2022)
Adsorption of the prototypical organic corrosion inhibitor benzotriazole on the Cu(100) surface
in Corrosion Science
Sung YY
(2022)
Surface Confined Hydrogenation of Graphene Nanoribbons.
in ACS nano
Angove E
(2022)
Highly Ordered N-Heterocyclic Carbene Monolayers on Cu(111).
in The journal of physical chemistry letters
Description | We have demonstrated the formation of highly ordered arrays of N-heterocyclic carbenes and triazoles on Cu, Ag and on oxidised Cu and Ag surfaces. We have demonstrated that Pt/alumina catalysts modified by the adsorption of N-heterocyclic carbenes can act as enantioselective heterogeneous catalysts for the hydrogenation of alpha-keto esters. |
Exploitation Route | NHC-functionalised surfaces have potential use in a range of applications including biosensing. NHCs can be effective corrosion inhibitors. Development of enantioselective heterogeneous catalysts may be exploited in the pharmaceutical sector. |
Sectors | Chemicals Pharmaceuticals and Medical Biotechnology Transport |
Description | The work carried out on the original project forms part of a collaboration with Queen's University, Canada. I am an international collaborator on a major project (began in 2022) funded by the Canadian government which includes academic and industrial partners. One of the main themes of this work is the development of NHCs as corrosion inhibitors for more reactive metals. Dissemination of the findings of our original project in the form of talks and posters at monthly online project meetings and annual meetings has raised interest among industrial partners. Commercial applications of this work may result eventually, though we are at an early stage in this process. In addition, our work on NHCs is of general interest in the context of corrosion inhibition to our industrial partners, Lubrizol, who have fully funded a PhD in my research group where we are investigating molecular corrosion inhibitors on metallic surfaces. Again, we are a long way from commercial applications in this context. |
First Year Of Impact | 2022 |
Impact Types | Societal |
Description | Protection of Metallic Surfaces from Bulk to Nano Through Molecular-Level Innovation |
Amount | $24,000,000 (CAD) |
Funding ID | NFRFT-2020-00573 |
Organisation | Natural Sciences and Engineering Research Council of Canada (NSERC) |
Sector | Public |
Country | Canada |
Start | 01/2022 |
End | 10/2024 |
Title | Adsorption of the prototypical organic corrosion inhibitor benzotriazole on the Cu(100) surface (dataset) |
Description | HREELS dataset for corresponding paper |
Type Of Material | Database/Collection of data |
Year Produced | 2022 |
Provided To Others? | Yes |
Impact | insight from this work has academic impact in the area of cu corrosion inhibition as well as in understanding the surface chemistry of N-heterocyclic molecules on coinage metal surfaces |
URL | https://risweb.st-andrews.ac.uk/portal/en/datasets/adsorption-of-the-prototypical-organic-corrosion-... |
Title | Highly Ordered N-Heterocyclic Carbene Monolayers on Cu(111) (dataset) |
Description | Dataset contains STM, HREELS and computational data |
Type Of Material | Database/Collection of data |
Year Produced | 2022 |
Provided To Others? | Yes |
Impact | academic impact only at this stage - demonstration of highly ordered NHC layers on Cu(111) |
URL | https://risweb.st-andrews.ac.uk/portal/en/datasets/highly-ordered-nheterocyclic-carbene-monolayers-o... |
Title | Investigation of copper and silver surfaces functionalised by N-heterocyclic molecules (thesis data) |
Description | Thesis dataset folder includes three folders and a JPG file. The three folders represent the thesis experimental chapters and include STM files (PAR, TB0, TB1, TF0 and TF1) that are accessible with WSxM 5.0 software, and TPD files (ascii containing X temperature in Kelvin and Y intensity) accessible with any text editor (E.g. Excel, Origin 2022). The data files are embargoed until 24/05/2024 |
Type Of Material | Database/Collection of data |
Year Produced | 2024 |
Provided To Others? | Yes |
URL | https://risweb.st-andrews.ac.uk/portal/en/datasets/investigation-of-copper-and-silver-surfaces-funct... |
Title | Surface confined hydrogenation of graphene nanoribbons (dataset) |
Description | HREELS information (Grillo) was crucial to the interpretation of data |
Type Of Material | Database/Collection of data |
Year Produced | 2022 |
Provided To Others? | Yes |
Impact | academic impact only at this stage |
URL | https://risweb.st-andrews.ac.uk/portal/en/datasets/surface-confined-hydrogenation-of-graphene-nanori... |
Description | Collaboration with Professors Cathleen M Crudden and J Hugh Horton (Queen's University, Canada) |
Organisation | Queen's University |
Country | Canada |
Sector | Academic/University |
PI Contribution | My research team are responsible for characterising the surfaces of metals and metal oxides that have been exposed to N-heterocyclic carbenes via vapour deposition in ultrahigh vacuum. |
Collaborator Contribution | Our project partners provide the N-heterocyclic carbene compounds for us to investigate. In addition, they carry out complementary surface characterisation measurements on samples where NHCs have been deposited from solution. |
Impact | N-heterocyclic carbene self-assembled monolayers on copper and gold ChemPhysChem 2017 DOI: 10.1002/cphc.201701045 Simple direct formation of self-assembled N-heterocyclic carbene monolayers on gold and their application in biosensing Nature Communications 2016 DOI: 10.1038/ncomms12654 |
Start Year | 2015 |
Description | A worshop on UHV techniques at Queen's University - Kingstron - ON - Canada |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Professional Practitioners |
Results and Impact | A talk describing the use of ultra-high vacuum techniques at an international workshop. The audience was very varied, consisted of about 120 people including academic and industrial partners, and policy makers. The outcome was an increase collaboration with different partners. |
Year(s) Of Engagement Activity | 2022 |
Description | Departmental Seminar - Chemistry Dept. - Queen's University, Kingston, ON, Canada |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Postgraduate students |
Results and Impact | A presentation was given describing adsorption studies of corrosion inhibitors from model to real substrates. The audience contained researchers covering all areas of Chemistry, especially organic and physical. Valuable insight was provided by discussions with experts in organic and physical chemistry and material science. This insight has been fed back into the development of the project, in particualr regarding the investigation of n-heterocyclic carbene based corrosion inhibitors. |
Year(s) Of Engagement Activity | 2019 |
Description | Departmental Seminar, University of Sussex |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | Local |
Primary Audience | Postgraduate students |
Results and Impact | Departmental Seminar |
Year(s) Of Engagement Activity | 2021 |
Description | RSC Solid Surfaces Group Symposium, Burlington House - RSC, London, UK, |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Undergraduate students |
Results and Impact | A poster was presented describing adsorption studies of corrosion inhibitors on model substrates. The audience contained researchers covering all areas of Surface Chemistry. Valuable insight was provided by discussions with experts in surface chemistry and material scientists. This insight has been fed back into the development of the project, in particualr regarding the use of new corrosion inhibitors and realistic/real substrates. |
Year(s) Of Engagement Activity | 2020 |
Description | Special Seminar - Chemical Engineering Dept. - Columbia University, New York, NY, USA |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Postgraduate students |
Results and Impact | A presentation was given describing adsorption studies of corrosion inhibitors from model to real substrates. The audience contained researchers covering all areas of Chemistry, especially compuational. Valuable insight was provided by discussions with experts in computational chemistry and material scientists. This insight has been fed back into the development of the project, in particualr regarding the investigation of Cu/Au bimetallic systems. |
Year(s) Of Engagement Activity | 2019 |
Description | Talk by Eloise Angove at 35th European Conference on Surface Science |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Postgraduate students |
Results and Impact | Conference talk presented by Eloise Angove entitled "Highly ordered N-heterocyclic carbene monolayers on Cu(111)" |
Year(s) Of Engagement Activity | 2022 |
Description | talk at ECOSS35 conference - University of Luxembourg |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Professional Practitioners |
Results and Impact | A talk describing recent progress on adsorption of corrosion inhibitors on model and realistic substrates. About 25 people in the audience, which was very engaged with discussions afterwards. |
Year(s) Of Engagement Activity | 2022 |