Enantiospecific Optical Sensing of Terpenes by an Aggregated Atropisomeric Platinum(II) Complex

Terpenes are unfunctionalized small volatile organic compounds (VOCs) that are naturally abundant, relevant to climate change, and impose potential health risks. Herein, we report a conceptually novel approach for the enantiospecific recognition of terpenes and other VOCs based on a square planar platinum(II) complex with an atropisomeric ligand. This molecular design results in chiral aggregated nanostructures caused by weak π-π- and metal-metal interactions with characteristic UV-vis absorption bands. Distinct UV-vis absorption changes are induced by weak intermolecular interactions with the enantiomers of diverse VOCs (2-butanol, 1-phenylethanol, α-pinene, and limonene) leading to perturbations of the chiral aggregates. This allows an enantiospecific, reversible detection of VOCs by UV-vis absorption spectroscopy in nonpolar solution. The study provides a new working principle for enantiospecific recognition with artificial optoelectronic noses, which are particularly promising for determining the enantiomers of unfunctionalized volatile organics.