Li-Wei Han

From 2D → 3D inclined polycatenation to 2D → 3D parallel polycatenation: a central metal cationic induce strategy

Two interesting entangled architectures, based on 44-sql subunits, showing interesting structure variation from 2D → 3D inclined polycatenation to 2D → 3D parallel polycatenation, are reported. The coordination geometries of the central metal cations are found very important in directing assemblies of the polycatenated networks.

Pore-size tuning in double-pillared metal–organic frameworks containing cadmium clusters

Based on a double pillared strategy, four non-interpenetrated cadmium metal–organic frameworks, showing interesting luminescence properties, have been reported. It is interesting that the pore sizes can be continuously tuned and with the elongation of the pillars, the frameworks turn from nbo net to mot net for different layer stacking fashions.

In Situ Growth of Metal–Organic Framework Thin Films with Gas Sensing and Molecule Storage Properties

New porous metal-organic framework (MOF) films based on the flexible ligand 1,3,5-tris[4-(carboxyphenyl)oxamethyl]-2,4,6-trimethylbenzene (H3TBTC) were fabricated on α-Al2O3 substrates under solvent thermal conditions. The factors affecting the fabrication of films, such as the temperature of pre-activation and the dosage of the reagents, were investigated. Tuning the subtle factors on film fabrications, a series of MOF thin films with different morphologies and grain sizes were prepared. The morphology and grain size of the films are monitored by scanning electron microscopy (SEM). X-ray diffraction (XRD) and attenuated total reflection infrared (ATR-IR) were also used to characterize the MOF films. The results indicate that the temperature of pre-activation and the dosage of the reagents are the key parameters during the process of film formation. The properties of the films, especially the sensing and sorption behavior, have been studied by an optical digital cameral and ultraviolet-visible (UV-vis) spectra. The evidence shows that the films are sensitive to small organic molecules, such as methanol and pyridine. Meanwhile, the films can adsorb small dye molecules. Thus, the films may have potential applications in either organic vapor sensing or storage of small dye molecules.

New types of hybrid solids of tetravanadate polyanions and cucurbituril

Three inorganic-organic hybrid solids based on tetravanadate polyanions, {V(4)O(12)}(4-) and cucurbituril, Me(10)Q[5] and Q[5], namely (NH(4))(4)[(V(4)O(12))·(Me(10)Q[5]@0.5H(2)O)(2)]·∼13H(2)O (1), Li(4)(H(2)O)(5)[(V(4)O(12))·(Me(10)Q[5]@H(2)O)(2)]·∼20H(2)O (2), and Na(4)(H(2)O)(2)[(V(4)O(12))·(Q[5])(2)]·∼15H(2)O (3), have been synthesized under hydrothermal conditions. In the structure of compound 1, two {Me(10)Q[5]@0.5H(2)O} moieties connect to one {V(4)O(12)}(4-) cluster through an NH(4)(+) counter-cation to form a trimer unit, which further forms a three-dimensional (3D) supramolecular architecture via extensive hydrogen bonds (H-bonds). Compound 2 contains a one-dimensional (1D) covalently bonded chain structure built by alternate {Me(10)Q[5]@H(2)O} moieties and {Li(2)O(4)(H(2)O)(3)}(2+) dimer units. The anionic {V(4)O(12)}(4-) units bond to every another {Li(2)O(4)(H(2)O)(3)}(2+) dimer unit sitting on the chain through multi-uncoordinated water molecules via H-bonds. Compound 3 is built from {V(4)O(12)}(4-) clusters, Q[5], and sodium cations into a two-dimensional (2D) covalent wavy structure, showing interesting connection between the building units, which is packed into 2D through plentiful H-bonds. It has been found that the cations dramatically affect the coordination of the tetravanadate polyanion and cucurbituril.

Absolute helicity induction: chiral information transfer from metal centre to the framework

Pseudo-achiral metal-centre driven spontaneous resolution occurred simultaneously in the formation of two Δ- and Λ-isomers of [CdBa(OBA)2(DMF)(CH3OH)(H2O)]·H2O (H2OBA = 4,4′-oxybis(benzoic acid)), which illustrated a clear relationship between chirality and helicity: the absolute sense of a double-helix made of achiral components is induced by metal centres in the two enantiomeric forms.

Cobalt-cluster-based coordination polymers with size-matching mixed ligands

A series of mixed ligand cobalt coordination polymers built by V-shaped O-donor ligand and linear N-donor ligand, namely [Co(BPE)(L)] (1), [Co3(BPE)2(HL)2(L)2] (2), and [Co5(BPE)2(OH)2(L)4]·4DMA (3) (H2L = 4,4′-(hexafluoroisopropylidene)-bis(benzoic acid), BPE = 1,2-di(4-pyridyl)ethane, DMA = dimethylacetamide), was synthesized under hydrothermal/solvothermal conditions. Compound 1 displays a two-dimensional (2-D) double layer structure of {Co2} clusters bridged by BPE and L2− ligands. Compounds 2 and 3 exhibit three-dimensional (3-D) networks built by {Co3} (2) and {Co5} (3) clusters, respectively, interconnected by BPE and L2− ligands. Topological analysis indicates compound 2 has a doubly interpenetrated (412·63)-pcu (α-Po, 6-connected) network, whereas compound 3 possesses an 8-connected (36·418·53·6)-hex network. It has been found that the reaction media and reaction conditions play key roles for the formation of cobalt clusters in the self-assemblies of compounds 1–3.

Control of Assembly of Dihydropyridyl and Pyridyl Molecules via Directed Hydrogen Bonding.

The crystallization of two dihydropyridyl molecules, 1,4-bis(4-(3,5-dicyano-2,6-dipyridyl)dihydropyridyl)benzene ([C40H24N10]·2DMF, 1·2DMF; DMF = dimethylformamide) and 1,4-bis(4-(3,5-dicyano-2,6-dipyridyl)dihydropyridyl)phenylbenzene ([C46H28N10]·2DMF, 3·2DMF), and their respective oxidized pyridyl analogues, 1,4-bis(4-(3,5-dicyano-2,6-dipyridyl)pyridyl)benzene ([C40H20N10], 2) and 1,4-bis(4-(3,5-dicyano-2,6-dipyridyl)pyridyl)phenylbenzene ([C46H24N10]·DMF, 4·DMF), has been achieved under solvothermal conditions. The dihydropyridyl molecules are converted to their pyridyl products via in situ oxidative dehydrogenation in solution. The structures of the four molecules have been fully characterized by single crystal and powder X-ray diffraction. The oxidized pyridyl products, 2 and 4, are more elongated due to aromatization of the dihydropyridyl rings at each end of their parent molecules 1 and 3, respectively. The solid-state supramolecular structures of the pyridyl molecules are distinct from the dihydropyridyl molecules in terms of their hierarchical assembly via hydrogen bonding due to the loss of primary N–H hydrogen bond donors in the two electron oxidized tectons. Overall, the geometrically shorter molecules 1 and 3 display close-packed structures, whereas the more extended 2 and 4 assemble into more open supramolecular systems.

CCDC 862545: Experimental Crystal Structure Determination

Related Article: Zu-Jin Lin, Li-Wei Han, Dong-Shuang Wu, Yuan-Biao Huang, Rong Cao|2013|Cryst.Growth Des.|13|255|doi:10.1021/cg301405r