Chiral metal-organic cages/containers (MOCs): From structural and stereochemical design to applications

During the past few decades, great efforts have been devoted to the design and self-assembly of discrete metal-organic cages/containers (MOCs) with increasing complexity and functionality. Among which, the incorporation of chirality into the construction of MOCs endows these supramolecular containers with unique potentials in stereochemical, nonlinear optical, biomedical and enzyme mimical fields. In this review, we give a brief survey of recent works focusing on the assembly and applications of chiral metal-organic convex polyhedra with well-defined three-dimensional (3D) outer shapes and inner cavities, including a few examples of chiral MOCs in other configurations. In general, the stereochemical origin of a chiral MOC can be generated through geometrical symmetry control pathways by removing the inherent inversion and/or mirror symmetries, in which the vertice-, edge-, and face-directed assembling approaches represent the most successful strategies to introduce stereogenic centers into and achieve absolute chiral environments in MOCs. Stereochemical memory, transfer and communication can be realized among different components of chiral MOCs in a supramolecular sense, resulting in cooperative and synergetic effects of chiral complex systems, which can be further explored for enantio-recognition, separation and asymmetric catalysis applications. (C) 2017 Elsevier B.V. All rights reserved.