Substrate-directed chiral selectivity of molecular self-assembled and covalent structures

Controlling the synthesis of low-dimensional chiral nanostructures on solid surfaces has attracted tremendous interest in recent years. Herein, we report a study showing substrate-directed chiral selectivity of molecular self-assemblies and polymers. Depositing prochiral 2,6-dibromo-anthracene (DBA) on Ag(111) and Ag(100) held at 120 K leads to the formation of a homochiral self-assembled structure and racemic self-assembly, respectively. Thermal annealing induces the stepwise formation of organometallic and covalent structures on the two surfaces. Similar to the low-temperature case, high chiral selectivity is achieved on Ag(111), where organometallic chains and covalent polymers are composed of homochiral DBA molecules, while poor chiral selectivity is found on Ag (100). This difference is presumably attributed to the lattice symmetry and substrate reactivity, as supported by the contrast experiments carried out on Au(111) and Cu(111). This work provides guidance for the construction of chiral low-dimensional nanomaterials on surfaces.

Automated summary

Controlling the synthesis of low-dimensional chiral nanostructures on solid surfaces has attracted significant interest. This study demonstrates the substrate-directed chiral selectivity of self-assemblies and polymers. Thermo-annealing results in the stepwise formation of organometallic and covalent structures on different surfaces, with high chiral selectivity achieved on Ag(111).