Enantioselective Synthesis of Intrinsically Chiral Nanocrystals

We have recently shown that it is possible to perform an enantioselective synthesis of inorganic nanostructures made of intrinsically chiral crystals, such as a-HgS, Te and Se. These crystals, belonging to the P3₁21 (or P3₂21) chiral space group, were grown as nanocrystals in the presence of thiolated chiral molecules, such as cysteine, penicillamine or glutathione. This led to a preference in the growth of the nanocrystals towards a certain handedness and consequent strong optical activity.

Furthermore, in the case of Te nanostructures particular synthesis conditions led to overall chiral shape of the elongated nanostructures, expressed as a twist on the scale of the size of the nanostructures of the order of 100 nm. Finally, the Te could be easily converted to other materials, such as gold or silver telluride, while preserving the chiral shape, opening the way to the formation of strongly optically active nanostructures made of various plasmonic or semiconductor materials.

We now demonstrate enantioselective synthesis of another class of materials: Lanthanide phosphate hydrate nanocrystals (also of chiral space group) in the presence of tartaric acid. The formed nanocrystals exhibit substantial degree of circularly polarized luminescence and their enantiomeric excess depends non-linearly on the enantiomeric excess of the tartaric acid ligands. We believe that this system may be useful for studying the mechanism of enantioselection of the formed nanocrystal seeds in the presence of the chiral molecules.