Abstract
Low-symmetry metal-organic cages (MOCs) can better mimic the structure of biological enzymes compared to high-symmetry MOCs, due to their unique internal cavities that resemble the specialized and irregular active sites of enzymes. In this study, two low-symmetry heteroleptic MOCs with six Pd(ii) centers, Pd(6)L(A) (6)L(B) (6) and Pd(6)L(B) (6)L(C) (6), were successfully constructed by combining two strategies: asymmetric ligand assembly and multi-ligand co-assembly. Crystallographic characterization and analysis revealed that Pd(6)L(A) (6)L(B) (6) is a mixture of potentially 16 isomers. Introducing a methyl group at the ortho position of the coordination site of ligand L(C) induced steric hindrance, driving Pd(6)L(B) (6)L(C) (6) to undergo a structural transformation and selectively assemble into a single dominant configuration from 13 potential isomers. This work not only demonstrates the immense potential of integrating asymmetric ligand assembly with multi-ligand co-assembly strategies but also highlights the critical role of steric effects in guiding assembly pathways and achieving precise configurational control in low-symmetry MOCs.