Renchun Zhang

Copper-Rich Framework Sulfides: A4Cu8Ge3S12 (A = K, Rb) with Cubic Perovskite Structure

Two copper-rich open-framework sulfides, K(4)Cu(8)Ge(3)S(12) (1) and Rb(4)Cu(8)Ge(3)S(12) (2), have been synthesized under solvothermal conditions. Compounds 1 and 2 are isostructural and contain icosahedral [Cu(8)S(12)](16-) clusters as basic building blocks. These clusters are primitive cubic packed and connect to one another by discrete Ge(4+) ions to generate 3D copper-rich Cu-Ge-S framework and form 3D channels along 100 directions where the alkali metal cations reside. These two open-framework sulfides crystallize in cubic perovskite structure.

3D porous metal-organic framework as an efficient electrocatalyst for nonenzymatic sensing application

Novel electroactive materials with high surface area and stability have great potential for electrochemical sensor. Herein, we demonstrate the exploitation of a porous Cu-based metal-organic framework (Cu-MOF) with large pore size as nonenzymatic sensors for the electrochemical determination of hydrogen peroxide (H2O2) and glucose. The Cu-MOF shows high stability even in NaOH solution. The as-prepared Cu-MOF modified carbon paste electrode (CPE) presents a well-behaved redox event from electroactive metal centers in the MOF at the physiological pH which can be utilized to catalyze the electroreduction of H2O2. It also exhibited excellent electrocatalytic activity towards the oxidation of glucose in alkaline solution. The results showed that the nonenzymatic sensors based on the Cu-MOF display excellent analytical performances, which make it a promising candidate in electrochemical sensor.

Syntheses and Characterization of a Series of Silver−Thioantimonates(III) and Thioarsenates(III) Containing Two Types of Silver−Sulfur Chains

Three framework silver-thioantimonates, K(3)Ag(9)Sb(4)S(12)(1), Rb(3)Ag(9)Sb(4)S(12)(2), and Cs(3)Ag(9)Sb(4)S(12)(3), and one layered silver-thioarsenate, CsAg(2)AsS(3)(4), have been synthesized solvothermally in the presence of thiophenol as a mineralizer. Compounds 1, 2, and 3 are isostructural and contain infinite silver-sulfur chains [Ag(9)S(12)](15-). These chains are connected to one another by the antimony atoms to generate wide channels along the [001] direction where the alkali metal cations reside. The structure of 4 consists of helical chains [Ag(2)S(3)](4-) linked by the arsenic atoms to form layers with potassium ions between the layers.

Quick synthesis of zeolitic imidazolate framework microflowers with enhanced supercapacitor and electrocatalytic performances

Novel zeolitic imidazolate framework-67 (ZIF-67) microflowers were synthesized by a quick and simple method without using any template or surfactant. Enhanced specific capacitance (188.7 F g−1 at 1 A g−1) and good cycle stability (remaining at 105% after 3000 cycles) of the ZIF-67 microflowers are observed in aqueous KOH electrolytes, which could be ascribed to the high chemical and thermal stabilities, large BET surface area, and small ion-transport (OH−) resistance of the hierarchical microflowers structure. In addition, the as-prepared ZIF-67 microflowers exhibited good electrocatalytic activity toward the reduction of H2O2. The obtained sensor also presented good reproducibility, high stability and a wide linear range. This work suggests that ZIF materials would be promising candidates for potential applications in supercapacitors and electroanalysis.

Glassy carbon electrode modified with 7,7,8,8-tetracyanoquinodimethane and graphene oxide triggered a synergistic effect: low-potential amperometric detection of reduced glutathione.

A sensitive electrochemical sensor based on the synergistic effect of 7,7,8,8-tetracyanoquinodimethane (TCNQ) and graphene oxide (GO) for low-potential amperometric detection of reduced glutathione (GSH) in pH 7.2 phosphate buffer solution (PBS) has been reported. This is the first time that the combination of GO and TCNQ have been successfully employed to construct an electrochemical sensor for the detection of glutathione. The surface of the glassy carbon electrode (GCE) was modified by a drop casting using TCNQ and GO. Cyclic voltammetric measurements showed that TCNQ and GO triggered a synergistic effect and exhibited an unexpected electrocatalytic activity towards GSH oxidation, compared to GCE modified with only GO, TCNQ or TCNQ/electrochemically reduced GO. Three oxidation waves for GSH were found at -0.05, 0.1 and 0.5V, respectively. Amperometric techniques were employed to detect GSH sensitively using a GCE modified with TCNQ/GO at -0.05V. The electrochemical sensor showed a wide linear range from 0.25 to 124.3μM and 124.3μM to 1.67mM with a limit of detection of 0.15μM. The electroanalytical sensor was successfully applied towards the detection of GSH in an eye drop solution.

Coordination-Induced Syntheses of Two Hybrid Framework Iodides: A Thermochromic Luminescent Thermometer

Two new 3D hybrid framework iodides, Hmta[(Hmta)Ag4I4] (1; Hmta = hexamethylenetetramine) and [(Hmta)2Ag8I6]I2 (2), have been synthesized under solvothermal conditions. Compound 1 consists of a neutral 3D framework built up from alternation of the tetrahedral Ag4I4 unit and Hmta with dia-b topology. Compound 2 features a 3D cationic framework with flu topology, constructed by cationic [Ag8I6](2+) units linked with Hmta. Tetrahedral Hmta plays crucial structure-directing roles in the formation of these 3D frameworks with high symmetry. The temperature-dependent photoluminescent measurement reveals luminescent thermochromism of the compounds, the emission maximum of which shows a gradual blue shift with increasing temperature. The results indicate that 1 is a promising wavelength- and intensity-dependent luminescent thermometer applicable in two different temperature ranges.

Solvothermal synthesis, crystal structure and photoluminescent property of a novel 3D [Ca 2 (HCOO) 2 (nds)(H 2 O) 2 ] n

A novel calcium(II) metal-organic framework [Ca2(HCOO)2(nds)(H2O)2]n(1) with mixed 1,5-naphthalene-disulfonate sodium salt(1,5-nds) and formate as organic ligands has been obtained under solvothermal conditions. It was found that the µ3- η2: η2 bridging mode of HCOO− in compound 1 is uncommon. Moreover, the formate, which was in situ formed from N,N′-dimethylformamide, played an important role in the formation of 3D structure. HCOO− ligands bridged Ca(II) ions into grid-like layers that were further pillared by the 1,5-nds ligand to form a 3D Ca-based framework. Compound 1 also exhibits a strong blue luminescence at room temperature.