Asymmetric Surfactants for the Synthesis of Chiral Gold Nanorods

Colloidal synthesis of chiral gold nanostructures is largely based on the use of chiral molecules that can induce asymmetric patterning to growing nanocrystals either by specifically binding to their surface [1] or by promoting the formation of helically structured micellar semi-hard templates [2]. Generally, chiral agents formed by molecules with local specific asymmetric centers are used (like amino acids with one or two asymmetric carbons) or compounds with conformational (or axial) chirality like binole or binamine. We report here synthesis of chiral gold nanorods exploiting molecules with a complex extensive chirality. Extensive chirality allows these molecules to direct the synthesis to asymmetric particles having different morpholgies, ranging from a pasteur like facial chirality, to chiral spyky gold nanorods depending on the conditions used. Along with different morphologies different chiroptical responses are obtained. The hybrid inorganic-organic systems are investigated using small-angle x-ray scattering (SAXS), UV-vis absorption and circular dichroism (CD). The obtained inorganic nanoparticles are structurally characterized by transmission electron microscopy 2D imaging and tomography. Optical properties of the inorganic nanoparticles are investigated by circular dichroism measurements. references: [1] B. Ni et al., Adv. Mater. 2023, 35, 2208299. [2] González-Rubio et al., Science 368,1472 (2020)