Synergizing Steric Hindrance and Stacking Interactions To Facilitate the Controlled Assembly of Multiple 4<sub>1</sub> Metalla‐Knots and <i>Pseudo</i>‐Solomon Links
Yan Zou, Shu‐Jin Bao, Haitong Tang, Hai‐Ning Zhang, Guo‐Xin Jin
Abstract
Abstract In this work, a noncoplanar terphenyl served as a building block to synthesize a novel 3,3′‐substituted bipyridyl ligand ( L1 ) which further reacted with binuclear half‐sandwich units A/B , giving rise to two aesthetic 4 1 metalla‐knots in high yields via a coordination‐driven self‐assembly strategy. Furthermore, given the inherent compactness of the 4 1 metalla‐knots, it creates favorable conditions for the emergence of steric repulsion. We focused on progressively introducing nitrogen atoms featuring a lone pair of electrons (LPEs) into ligand L1 to manipulate the balance of H⋅⋅⋅H/LPEs⋅⋅⋅LPEs steric repulsion during the assembly process, ultimately achieving controlled assembly from 4 1 metalla‐knots to the pseudo ‐Solomon link and then to molecular tweezer‐like assembly facilitated by stacking interactions. All the assemblies were well characterized by solution‐state NMR techniques, ESI‐TOF/MS, and single‐crystal X‐ray diffraction. The evolutionary process of the topological architectures is equivalent to visualizing the synergistic effect of steric hindrance and stacking interactions on structural assembly, providing a new avenue for achieving the controlled synthesis of different topologies.