How to not build a cage: endohedral functionalization of polyoxometalate-based metal–organic polyhedra
Ji Feng Guo, Qing Chang, Zhiwei Liu, Yangming Wang, Chuanhong Liu, Mou Wang, Danmeng Huang, Guanying Chen, Hongmei Zhao, Wei Wang, Xikui Fang
Abstract
. Replacing the central sulfates of these hexavanadate clusters with more strongly coordinating phosphonate groups allows the installation of functionalities within the cage cavities. Organophosphonates with phenyl, biphenyl, and terphenyl tails were examined for internalization. Depending on the size/shape of the cavities, small phosphonates can fit into the molecular containers whereas larger ones inhibit or transform the framework architecture, whereby the first non-cage complex was isolated from a reaction that otherwise would lead to entropically favored regular polyhedra cages. The results highlight the complex and dynamic nature of the self-assembly process involving polyoxometalates and the scope of molecular variety accessible by the introduction of endo functional groups.