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Chirality is a fascinating phenomenon for recent electrochemistry and materials research, allowing for the preparation of detection platforms based on analyte enantiodiscrimination and the development of advanced chiroptical devices and chiral electrodes. In this Viewpoint, we highlight new directions in the field of chiral helical polyaromatic molecules (mainly helicenes) that are useful for the preparation of optically and redox-active polymers and/or self-assembled thin layers, nanostructures and functional electrode surfaces. Instead of the previously reported chiral materials prepared by molecular imprinting, a concept based on the preparation of inherently chiral helicene-based materials with (opto)electrochemical applicability is presented. A short overview of well-established electrochemical methods for the research of chiral molecules is also outlined.

The utilization of chiroplasmonic effects provides unique feasibility in the fields of enantioselective detection and recognition. In this work, the chiroplasmonic fiber probes were created through the coupling of a highly optically active dielectric medium with intrinsically non-chiral plasmon-active nanostructures. The specifically designed enantiomers of helicenes with a huge optical rotation were selectively immobilized to thin gold and silver layers deposited on an optical fiber core. The chirality transfer from helicene enantiomers to closed plasmon active noble metals films results in excitation of chiral plasmon waves with opposite rotation on gold or silver surfaces. The created chiroplasmon-active optical fiber probes were used for environmental chirality monitoring and found to be sensitive to the presence of left- or right-handed molecules (glucose enantiomers) or biomolecules conformation (β-Lactoglobulin) in surrounding solutions. Control experiments confirmed that observed chirality-related plasmon band shift can be attributed to the interaction of chiral plasmon waves with the external environment, but not to the immobilization of probing molecules on the fiber surface. Created structures allow us to simultaneously estimate the presence of optically active molecules, with both, point or conformation chirality, and provides the ability to studying chiral macromolecular structure of proteins.

This short paper describes the preparation of thin layers based on carbohelicenes, which are inherently chiral polyaromatics existing in the enantiomeric forms P and M. Specifically, [5]-, [6]- and [7]helicene were subjected to redox cycling between −1.5 and 1.5 V vs. ferrocene/ferrocenium at a scan rate of 10 V/s. This way, enantiopure layers exhibiting redox activity were formed on the surfaces of the glassy carbon and ITO electrodes under anoxic and non-aqueous conditions. The properties of the prepared polymer layers were investigated using electrochemistry with Fe/Ru redox probes, circular dischroism, AFM, impedance measurement and Raman spectroscopy. With [6]helicene, the suggested electropolymerization procedure thus represents a proof-of-concept for the preparation of chiral carbonaceous surfaces. Keywords: Carbohelicene, Hexahelicene, Voltammetry, Enantiopure, Redox active, Chiral carbon