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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.
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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
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Irziqat B, Cebrat A, Baljozović M, Martin K, Parschau M, Avarvari N, Ernst KH. Stereospecific on-Surface Cyclodehydrogenation of Bishelicenes: Preservation of Handedness from Helical to Planar Chirality. Chemistry 2021; 27:13523-13526. [PMID: 34387926 PMCID: PMC8518606 DOI: 10.1002/chem.202102069] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Indexed: 11/24/2022]
Affiliation(s)
- Bahaaeddin Irziqat
- Molecular Surface Science and Coating Technology Laboratory, Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600, Dübendorf, Switzerland
| | - Aleksandra Cebrat
- Molecular Surface Science and Coating Technology Laboratory, Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600, Dübendorf, Switzerland
| | - Miloš Baljozović
- Molecular Surface Science and Coating Technology Laboratory, Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600, Dübendorf, Switzerland
| | - Kévin Martin
- MOLTECH-Anjou UMR 6200, CNRS, UNIV Angers, 2 bd Lavoisier, 49045, Angers Cedex, France
| | - Manfred Parschau
- Molecular Surface Science and Coating Technology Laboratory, Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600, Dübendorf, Switzerland
| | - Narcis Avarvari
- MOLTECH-Anjou UMR 6200, CNRS, UNIV Angers, 2 bd Lavoisier, 49045, Angers Cedex, France
| | - Karl-Heinz Ernst
- Molecular Surface Science and Coating Technology Laboratory, Empa, Swiss Federal Laboratories for Materials Science and Technology, Überlandstrasse 129, 8600, Dübendorf, Switzerland.,Nanosurf Laboratory, Institute of Physics, The Czech Academy of Sciences, Cukrovarnická 10, 162 00, Prague, Czech Republic.,Department of Chemistry, University of Zurich, Winterthurerstrasse 190, 8057, Zürich, Switzerland
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Possible Physical Basis of Mirror Symmetry Effect in Racemic Mixtures of Enantiomers: From Wallach’s Rule, Nonlinear Effects, B–Z DNA Transition, and Similar Phenomena to Mirror Symmetry Effects of Chiral Objects. Symmetry (Basel) 2020. [DOI: 10.3390/sym12060889] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Effects associated with mirror symmetry may be underlying for a number of phenomena in chemistry and physics. Increase in the density and melting point of the 50%L/50%D collection of enantiomers of a different sign (Wallach’s rule) is probably based on a physical effect of the mirror image. The catalytic activity of metal complexes with racemic ligands differs from the corresponding complexes with enantiomers as well (nonlinear effect). A similar difference in the physical properties of enantiomers and racemate underlies L/D inversion points of linear helical macromolecules, helical nanocrystals of magnetite and boron nitride etc., B–Z DNA transition and phenomenon of mirror neurons may have a similar nature. Here we propose an explanation of the Wallach effect along with some similar chemical, physical, and biological phenomena related to mirror image.
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Сhiral and Racemic Fields Concept for Understanding of the Homochirality Origin, Asymmetric Catalysis, Chiral Superstructure Formation from Achiral Molecules, and B-Z DNA Conformational Transition. Symmetry (Basel) 2019. [DOI: 10.3390/sym11050649] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The four most important and well-studied phenomena of mirror symmetry breaking of molecules were analyzed for the first time in terms of available common features and regularities. Mirror symmetry breaking of the primary origin of biological homochirality requires the involvement of an external chiral inductor (environmental chirality). All reviewed mirror symmetry breaking phenomena were considered from that standpoint. A concept of chiral and racemic fields was highly helpful in this analysis. A chiral gravitational field in combination with a static magnetic field (Earth’s environmental conditions) may be regarded as a hypothetical long-term chiral inductor. Experimental evidences suggest a possible effect of the environmental chiral inductor as a chiral trigger on the mirror symmetry breaking effect. Also, this effect explains a conformational transition of the right-handed double DNA helix to the left-handed double DNA helix (B-Z DNA transition) as possible DNA damage.
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