Guan-Hua Wang

Synthesis, characterization and assembly of BiOCl nanostructure and their photocatalytic properties

In this article, a two-dimensional (2D) nanoplate and a 3D hierarchical structure of BiOCl were synthesized through a simple sonochemical route. Compared with previous preparation methods, the 2D nanoplates can be prepared at a relatively short time (about 30 min) with low energy used. Additionally, these 2D nanoplates can easily assemble into a 3D hierarchical structure with the surfactant reagents. The obtained products were well crystallized and subsequently characterized by a range of methods, such as X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), high-resolution transmission microscopy (HRTEM), selected area electron diffraction (SAED) and Raman spectroscopy. A possible mechanical growth route was also proposed based on the experiments. The photocatalytic properties of the prepared samples were further investigated by photocatalytic decomposition of Methene Orange (MO) dye, which indicated that the 3D hierarchical structure can effectively improve photocatalytic activity.

Metal–organic frameworks based on the pyridine-2,3-dicarboxylate and a flexible bispyridyl ligand: syntheses, structures, and photoluminescence

Three new metal–organic coordination polymers, [Cu(2,3-pydc)(bpp)]·2.5H2O (1), [Zn(2,3-pydc)(bpp)]·2.5H2O (2) and [Cd(2,3-pydc)(bpp)(H2O)]·3H2O (3) (2,3-pydcH2 = pyridine-2,3-dicarboxylic acid, bpp = 1,3-bis(4-pyridyl)propane), have been synthesized at room temperature. All complexes have metal ions serving as 4-connected nodes but represent two quite different structural motifs. Complexes 1 and 2 are isomorphous, both of which feature 2D → 3D parallel interpenetration. Each two-dimensional (2D) layer with (4, 4) topology is interlocked by two nearest neighbours, one above and one below, thus leading to an unusual 3D motif. Complex 3 has a non-interpenetrating 3D CdSO4 framework with cavities occupied by uncoordinated water molecules. The compounds have been characterized by infrared spectroscopy, elemental analysis, thermogravimetric analysis and X-ray crystallography. The photoluminescent studies of 2 and 3 show that both complexes exhibit intense fluorescent emissions at room temperature.

Construction of coordination networks with high connectivity: a new 8-connected self-penetrating network based on tetranuclear metal clusters

Two highly connected cobalt(II) and zinc(II) coordination polymers with tetranuclear metal clusters as the nodes of network have been prepared, being the first example of an 8-connected self-penetrating net based on a cross-linked α-Po subnet.

Supramolecular isomerism in zinc hydroxide coordination polymers with pyridine-2,4-dicarboxylic acid: Two polymorphs with centrosymmetric two-dimensional and acentric three-dimensional coordination networks

Reactions of Zn(BF4)2 and pyridine-2,4-dicarboxylic acid (2,4-pydcH2) in the presence of 1,2-bis(4-pyridyl)ethylene or 1,3-bis(4-pyridyl)propane under hydro(solvo)thermal conditions yielded two polymorphic metal–organic coordination polymers formulated as Zn2(OH)2(2,4-pydc) (1 and 2). Polymorph 1 features a two-dimensional (2-D) layer-like structure that is constructed by 2,4-pydc ligands bridging between the Zn–OH–Zn double-chain units. Each single Zn–OH–Zn chain is composed of μ2-OH groups connecting trigonal bipyramidal and tetrahedral Zn centers. Polymorph 2 is a 3-D coordination polymer containing 2-D Zn–OH–Zn sheets that consist of μ2- and μ3-OH groups and trigonal bipyramidal Zn centers. The sheets are pillared by 2,4-pydc ligands to form an acentric structural architecture. 1 and 2 are rare examples that the two polymorphs exhibit a centrosymmetric 2-D coordination network and an acentric 3-D coordination network, respectively. The different structures lead to differences in photoluminescent properties and thermal stabilities for 1 and 2.

Constructing porous frameworks from one-dimensional cobalt-oxygen clusters and pyridinedicarboxylate ligands adopting two rare coordination modes

A porous material with cobalt–oxygen cluster framework has been synthesized hydrothermally, which possesses large and rigid channels and manifests strong antiferromagnetic interactions, and the pyridinedicarboxylate ligand exhibits two types of rare coordination modes.

catena-Poly[diammonium [diaqua­bis(pyridine-2,4-dicarboxyl­ato-κ2N,O2)cuprate(II)] [[diaqua­copper(II)]-μ-pyridine-2,4-dicarboxyl­ato-κ3N,O2:O2′-[tetra­aqua­cadmium(II)]-μ-pyridine-2,4-dicarboxyl­ato-κ3O2:N,O2′] hexa­hydrate]

The title mixed-metal complex, {(NH4)2[Cu(C7H3NO4)2(H2O)2][CdCu(C7H3NO4)2(H2O)6]·6H2O}n, contains one octahedrally coordinated CdII center and two octahedrally coordinated CuII centers, each lying on an inversion center. The two CuII atoms are each coordinated by two O atoms and two N atoms from two 2,4-pydc (2,4-H2pydc = pyridine-2,4-dicarboxylic acid) ligands in the equatorial plane and two water molecules at the axial sites, thus producing two crystallographically independent [Cu(2,4-pydc)2(H2O)2]2− metalloligands. One metalloligand exists as a discrete anion and the other connects the Cd(H2O)4 units, forming a neutral chain. O—H⋯O and N—H⋯O hydrogen bonds connects the polymeric chains, complex anions, ammonium cations and uncoordinated water molecules into a three-dimensional supramolecular network.

Cubic spinel In4SnS8: electrical transport properties and electrochemical hydrogen storage properties

In this work, electrical transport properties and electrochemical hydrogen storage properties of a cubic spinel In(4)SnS(8) hierarchical nanostructure were investigated. A simple single layer device exhibits non-linear current-voltage (I-V) characteristics. The detailed electrical transport properties of the sample indicated that the conduction mechanism varied in different external voltage regions. Derived from the typical spinel system of the A[B(2)]X(4) (A: Zn, Cu, Sn, B: In, Ga, X: S, Se) ternary chalcogenides, this thiospinel compound also shows high electrochemical hydrogen storage of 127 mAh g(-1) and its mechanism is discussed.

Comparative Determination of the Volatile Components of Prunella vulgaris L. from Different Geographical Origins by Headspace Solid-Phase Microextraction and Gas Chromatography-Mass Spectrometry

The volatile components of Prunella vulgaris L. were determined by headspace solid-phase microextraction (HS-SPME) combined with gas chromatography-mass spectrometry (GC-MS). The optimal conditions for HS-SPME were 1.5 g of sample, extraction using a polydimethylsiloxane-divinylbenzene fiber for 50 min at 90°C, and a desorption time of 5 min. The volatile compounds of Prunella vulgaris L. from different parts of the herb (cultivated in Jiangsu) and from different geographical regions (Jiangsu, Fujian, Guangxi, Hunan, and Zhejiang) were comparatively analyzed. There were 26, 28, 28, 28, and 34 compounds identified in Prunella vulgaris L. from Jiangsu, Fujian, Guangxi, Hunan, and Zhejiang, respectively. Among them, the following 12 were found in all origins: 1-nonanol, dodecane, tridecane, α-bourbonene, tetradecane, geranyl acetone, pentadecane, caryophyllene oxide, hexadecane, tetradecanal, isobutyl phthalate, and n-butyl hexadecanoate. In addition, Prunella vulgaris L. cultivated in Guangxi and Zhejiang had a high similarity in volatile components as did Prunella vulgaris L. cultivated in Fujian and Hunan. The results provided valuable information for the application of Prunella vulgaris L. and suggested that the HS-SPME method was suitable for differentiating and determining the volatile components of Prunella vulgaris L.

A smart copper(II)-responsive binuclear gadolinium(III) complex-based magnetic resonance imaging contrast agent

A novel Gd-DO3A-type bismacrocyclic complex, [Gd2(DO3A)2BMPNA], with a Cu2+-selective binding unit was synthesized as a potential “smart” copper(II)-responsive magnetic resonance imaging (MRI) contrast agent. The relaxivity of the complex was modulated by the presence or absence of Cu2+; in the absence of Cu2+, the complex exhibited a relatively low relaxivity value (6.40 mM−1 s−1), while the addition of Cu2+ triggered an approximately 76% enhancement in relaxivity (11.28 mM−1 s−1). Moreover, this Cu2+-responsive contrast agent was highly selective in its response to Cu2+ over other biologically-relevant metal ions. The influence of some common biological anions on the Cu2+-responsive contrast agent and the luminescence lifetime of the complex were also studied. The results of the luminescence lifetime measurements indicated that the enhancement in relaxivity was mainly ascribed to the increased number of inner-sphere water molecules binding to the paramagnetic Gd3+ core upon the addition of Cu2+. In addition, the visual change associated with the significantly enhanced relaxivity due to the addition of Cu2+ was observed from T1-weighted phantom images.

Tetra­aqua­(1,10-phenanthroline-κ2N,N′)cobalt(II) dinitrate: a hydrogen-bonded supra­molecular network

The structure of the title compound, [Co(C12H8N2)(H2O)(4)]-(NO3)(2), consists of tetraaqua(1,10- phenanthroline)cobalt(II) cations and nitrate anions. The Co atom is located on a twofold rotation axis and is coordinated by the two N atoms of a 1,10-phenanthroline ligand and four O atoms of water molecules. The cations and anions are linked by hydrogen-bond interactions into a three-dimensional supramolecular network.