Charge-switchable Metal-organic Framework for Size/Charge-selective Molecular Inclusions

Highly size/charge-selective molecular inclusions by a charge-switchable zinc-based metal-organic framework (Zn-MOF) have been achieved, which comprises of two kinds of paddle-wheel building units and four kinds of nanocages. Featuring counter anions floating in the pore and accessible coordination sites on the skeleton, Zn-MOF represents exceptional versatility in taking up anionic dyes by ion-exchange, cationic dyes by charge switch of skeleton, and neutral organic dyes by host-guest interactions. Both size and charge selectivities in the molecular inclusion by the charged nanocages in Zn-MOF provide an efficient way in designing superior porous materials with an enhanced level of compatibility and recognition.