Crystalline capsules: metal-organic frameworks locked by size-matching ligand bolts.

Metal-organic frameworks (MOFs) are shown to be good examples of a new class of crystalline porous materials for guest encapsulation. Since the encapsulation/release of guest molecules in MOF hosts is a reversible process in nature, how to prevent the leaching of guests from the open pores with minimal and nondestructive modifications of the structure is a critical issue. To address this issue, we herein propose a novel strategy of encapsulating guests by introducing size-matching organic ligands as bolts to lock the pores of the MOFs through deliberately anchoring onto the open metal sites in the pores.

A flexible zwitterion ligand based lanthanide metal-organic framework for luminescence sensing of metal ions and small molecules.

A new lanthanide metal-organic framework was constructed using a tripodal flexible zwitterion ligand (H3LBr3) which takes a chair-shaped configuration. The luminescence of the compound displays highly selective sensing of the Fe(3+) ion and nitrobenzene.

In vitro controlled release of theophylline from metal-drug complexes.

Two new metal-drug complexes constructed from non-toxic zinc and theophylline (TPL), an anti-asthmatic active drug, have been introduced into a release system based on matrices of hydroxypropylmethylcellulose (HPMC) and microcrystalline cellulose (MC). The release rate of TPL from the metal-drug complexes could be controlled by the amount of MC added, and the release mechanism changed from anomalous transport to Fickian diffusion.

Chiral uranyl-organic compounds assembled with achiral furandicarboxylic acid by spontaneous resolution.

Influenced by different cations in the self-assembly of chiral units, achiral (UOC-NH4, UOC-Ca) and chiral (UOC-Na) uranyl-organic compounds were obtained from achiral reactants. The photocatalytic activity of UOC-Na was also investigated.