Narcissistic, Integrative, and Kinetic Self-Sorting within a System of Coordination Cages

Many useful principles of self-assembly have been elucidated through studies of systems where multiple components combine to create a single structure. More complex systems, where multiple product structures self-assemble in parallel from a shared set of precursors, are also of great interest, as biological systems exhibit this behavior. The greater complexity of such systems leads to an increased likelihood that discrete species will not be formed, however. Here we show how the kinetics of self-assembly govern the formation of multiple metal–organic architectures from a mixture of five building blocks, preventing the formation of a discrete structure of intermediate size. By varying ligand symmetry, denticity, and orientation, we explore how five distinct polyhedraa tetrahedron, an octahedron, a cube, a cuboctahedron, and a triangular prismassemble in concert around CoII template ions. The underlying rules dictating the organization of assemblies into specific shapes are deciphered, explaining the formation of only three discrete entities when five could form in principle.

通过对多组分结合形成单一结构的体系开展研究，诸多自组装（self-assembly）的实用原理已被阐明。而由共享前驱体（precursors）并行自组装出多种产物结构的更为复杂的体系，同样极具研究价值，因为生物系统正展现出此类行为。然而，这类体系的更高复杂度会提升无法形成离散物种的概率。本文中，我们揭示了自组装动力学如何调控五种构筑单元（building blocks）的混合物生成多种金属有机组装体的过程，并阻止了中等尺寸离散结构的形成。通过改变配体（ligand）的对称性、齿度（denticity）与取向，我们探究了五种不同的多面体——四面体（tetrahedron）、八面体（octahedron）、立方体（cube）、立方八面体（cuboctahedron）以及三角棱柱（triangular prism）——如何在二价钴（CoII）模板离子周围协同组装。本研究解析了指导组装体形成特定形貌的内在规律，阐明了为何理论上可形成的五种结构，最终仅生成三种离散实体。