|
1
|
Ernst KH. Helicenes on Surfaces: Stereospecific On-Surface Chemistry, Single Enantiomorphism, and Electron Spin Selectivity. Chirality 2024; 36:e23706. [PMID: 39077832 DOI: 10.1002/chir.23706] [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: 06/06/2024] [Revised: 07/07/2024] [Accepted: 07/09/2024] [Indexed: 07/31/2024]
Abstract
Helicenes represent an important class of chiral organic material with promising optoelectronic properties. Hence, functionalization of surfaces with helicenes is a key step towards new organic material devices. This review presents different aspects of adsorption and modification of metal surfaces with different helicene species. Topics addressed are chiral crystallization, that is, 2D conglomerate versus racemate crystallization, breaking of mirror-symmetry in racemates, chirality-induced spin selectivity, and stereoselective on-surface chemistry.
Collapse
Affiliation(s)
- Karl-Heinz Ernst
- Molecular Surface Science, Empa, Swiss Federal Laboratories for Materials Science and Technology, Dübendorf, Switzerland
- Nanosurf Lab, Institute of Physics of the Czech Academy of Sciences, Prague 6, Czech Republic
- Department of Chemistry, University of Zurich, Zürich, Switzerland
| |
Collapse
|
|
2
|
Wade J, Salerno F, Kilbride RC, Kim DK, Schmidt JA, Smith JA, LeBlanc LM, Wolpert EH, Adeleke AA, Johnson ER, Nelson J, Mori T, Jelfs KE, Heutz S, Fuchter MJ. Controlling anisotropic properties by manipulating the orientation of chiral small molecules. Nat Chem 2022; 14:1383-1389. [PMID: 36302869 DOI: 10.1038/s41557-022-01044-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 08/22/2022] [Indexed: 01/04/2023]
Abstract
Chiral π-conjugated molecules bring new functionality to technological applications and represent an exciting, rapidly expanding area of research. Their functional properties, such as the absorption and emission of circularly polarized light or the transport of spin-polarized electrons, are highly anisotropic. As a result, the orientation of chiral molecules critically determines the functionality and efficiency of chiral devices. Here we present a strategy to control the orientation of a small chiral molecule (2,2'-dicyano[6]helicene) by the use of organic and inorganic templating layers. Such templating layers can either force 2,2'-dicyano[6]helicene to adopt a face-on orientation and self-assemble into upright supramolecular columns oriented with their helical axis perpendicular to the substrate, or an edge-on orientation with parallel-lying supramolecular columns. Through such control, we show that low- and high-energy chiroptical responses can be independently 'turned on' or 'turned off'. The templating methodologies described here provide a simple way to engineer orientational control and, by association, anisotropic functional properties of chiral molecular systems for a range of emerging technologies.
Collapse
Affiliation(s)
- Jessica Wade
- Department of Materials and London Centre for Nanotechnology, Imperial College London, London, UK.
- Centre for Processable Electronics, Imperial College London, London, UK.
| | - Francesco Salerno
- Centre for Processable Electronics, Imperial College London, London, UK
- Department of Chemistry and Molecular Sciences Research Hub, Imperial College London, London, UK
| | - Rachel C Kilbride
- Department of Physics and Astronomy, The University of Sheffield, Sheffield, UK
| | - Dong Kuk Kim
- Department of Materials and London Centre for Nanotechnology, Imperial College London, London, UK
- Centre for Processable Electronics, Imperial College London, London, UK
| | - Julia A Schmidt
- Department of Chemistry and Molecular Sciences Research Hub, Imperial College London, London, UK
| | - Joel A Smith
- Department of Physics, Clarendon Laboratory, University of Oxford, Oxford, UK
| | - Luc M LeBlanc
- Department of Chemistry, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Emma H Wolpert
- Department of Chemistry and Molecular Sciences Research Hub, Imperial College London, London, UK
| | - Adebayo A Adeleke
- Department of Chemistry, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Erin R Johnson
- Department of Chemistry, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Jenny Nelson
- Centre for Processable Electronics, Imperial College London, London, UK
- Department of Physics, Imperial College London, London, UK
| | - Tadashi Mori
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, Suita, Japan
| | - Kim E Jelfs
- Centre for Processable Electronics, Imperial College London, London, UK
- Department of Chemistry and Molecular Sciences Research Hub, Imperial College London, London, UK
| | - Sandrine Heutz
- Department of Materials and London Centre for Nanotechnology, Imperial College London, London, UK
- Centre for Processable Electronics, Imperial College London, London, UK
| | - Matthew J Fuchter
- Centre for Processable Electronics, Imperial College London, London, UK.
- Department of Chemistry and Molecular Sciences Research Hub, Imperial College London, London, UK.
| |
Collapse
|