Huadong Guo

An unusual 3D polycatenane motif generated by the 2D → 2D parallel → 3D parallel interpenetration of (4,4) sheets

A fascinating 3D polycatenane-like metal–organic framework with two kinds of helical chains was reported, in which the helical chains exhibit multiple interweaving modes based on the unusual 2D → 2D parallel → 3D parallel interpenetration.

Entangled metal–organic frameworks modulated by N-donor ligands of different conformations

Based on the aromatic dicarboxylic acid and N-donor ligands with different conformations, four Zn(II) metal–organic frameworks, namely [Zn(mfda)(L1)] (1), [Zn2(mfda)2(L2)]·DMF·H2O (2), [Zn2(mfda)2(L3)(H2O)]·DMF (3) and [Zn2(mfda)2(L4)] (4) have been synthesized (mfda = 9,9- dimethylfluorene-2,7-dicarboxylate anion, L1 = 1,10-phenanthroline, L2 = 4,4′-bipyridine, L3 = 2,5-bis(4-pyridyl)-1,3,4-ocadiazole and L4 = 1,4-bis(imidazol-1-ylmethyl)benzene). Single-crystal X-ray diffraction has revealed that all compounds exhibit entangled structures. Compound 1 is composed of 1D zigzag chains that are entangled through the π–π stacking interactions to generate a three-fold interpenetrating diamond-like networks. 2 exhibits a two-fold interpenetrating (α-Po) net, which leaves 1D channels with high free volume. In 3, parallel mutual polythreadings of 2D layers are connected by hydrogen bonds into a self-penetrating framework with (44·610·7)(4·5·6)(46·52·616·73·9) topology. For 4, the interpenetrating 2D layers are connected into a self-interpenetrating net with (49·66) topology. The potential of N-donor ligands to produce interesting metal–organic frameworks is investigated. Luminescent studies show that 1–4 exhibit strong blue fluorescent emissions.

Interweaving of single-helical and equal double-helical chains with the same helical axis in a 3D metal–organic framework

A novel metal–organic framework with unprecedented interweaving of coaxial single-helical and equal double-helical chains of opposite chirality, which features a super-connective helix simultaneously tangling with eight helices, was reported.

Five three/two-fold interpenetrating architectures from self-assembly of fluorene-2,7-dicarboxylic acid derivatives and d10 metals

Five new three/two-fold interpenetrated coordination polymers, namely, [Cd(mfda)(L1)] (1), [Cd(efda)(L1)] (2), [Zn2(mfda)2(L2)]·DMF·H2O (3), [Zn2(efda)2(L2)]·(DMF)0.25, (4) and [Cd2(mfda)2(L2)2]·DMF·H2O (5) (H2mfda = 9,9-dimethylfluorene-2,7-dicarboxylic acid, H2efda = 9,9-diethylfluorene-2,7-dicarboxylic acid, L1 = Methylene bis(3,5-dimethylpyrazole) and L2 = 1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene), have been synthesized under solvent-thermal conditions with mixed ligands. Compounds 1 and 2 are isostructural and possess two-dimensional (6, 3) layered structures containing two kinds of rings. Three equivalent (6, 3) net interpenetrate in a parallel fashion to form an unprecedented mat-like 2D sheet. Compounds 3 and 4 are almost identical in structure and display threefold interpenetrating α–Po net structures. Compound 5 displays a twofold interpenetrated 3D 6-connected net with α–Po topology. The luminescent properties of these compounds have been studied in the solid state at room temperature.

A three-dimensional metal–organic framework based on a triazine derivative: syntheses, structure analysis, and sorption studies

A novel metal–organic framework [Cu3(m-TATB)2Py(CH3OH)2] (1) constructed of a triazine-based trigonal-planar ligand, 3,3′,3″-s-triazine-2,4,6-triyltribenzoate (m-H3TATB), has been synthesized and structurally characterized. Compound 1 features three-dimensional (3D) channels and cavities together, and exhibits high carbon dioxide sorption at normal pressure.