Steric Hindrance Effect as a Decisive Factor for the Self-Assembly of Metallocages

Abstract

In the past decades, many supramolecular cages with different sizes and shapes have been achieved through coordination-driven self-assembly. However, the strategy of topology adjustment by using a steric hindrance effect has not been fully developed. In this Article, we report the synthesis of ligand LA with rotatable arms, ligand LB with restricted arms, and their precisely controlled self-assembly to tetramer cage T1 and dimer cage D1, respectively, under the same conditions. By utilizing the steric hindrance of the ligands, the shapes and sizes of metallosupramolecular cages have been successfully adjusted. The metallocages were characterized by NMR spectroscopy ( 1 H, 13 C, COSY, NOESY, and DOSY), mass spectrometry (ESI-MS, TWIM-MS), transmission electron microscopy, and atomic force microscopy. This synthetic method would have the potential to be a general strategy for the design and self-assembly of diverse cages with tunable shape, size, and applicable properties.

Synthesis of a Triangle-Fused Six-Pointed Star and Its Electrocatalytic CO2 Reduction Activity

“…Transmission electron microscopy (TEM) and atomic force microscopy (AFM) were employed to further provide the shape and size information on R1 and T1 . Solutions of R1 and T1 at concentrations of about 10 –7 M (solvent acetonitrile) were deposited on superthin carbon film-coated grids (Cu, 400 mesh) for testing, respectively.…”