Synthesis,Crystal Structure,Fluorescence Properties and Geometrical Calculation of 4,8,10-Trimethyl-2-(3,5-dimethylpyrazol)-pyrido-[2',3':3,4]-pyrazol[1,5-a]-pyrimidin

A novel compound 4,8,10-trimethyl-2-（3,5-dimethylpyrazol）-pyrido-[2＇,3＇：3,4]-py-razol-[1,5-5-a]-pyrimidine（C17H18N6） has been synthesized from 2,6-dichloro-4-methylnico-tino-nitrile,hydrazine and acetylacetone by substitution and cyclolization.The structure was charac-terized by elemental analysis,1H NMR and IR,and single-crystal structure was determined by X-ray diffraction analysis.The compound crystallizes in the monoclinic system,space group P21/c with a = 8.0338（9）,b = 28.618（3）,c = 7.2688（8）,β = 111.051（2）o,V = 1559.6（3） 3,Z = 4,Dc = 1.305 g/cm3,μ = 0.083 mm-1,Mr = 306.37,F（000） = 648,S = 0.971,the final R = 0.0795 and wR = 0.1746 for 1457 observed reflections（Ⅰ 〉 2σ（Ⅰ））.The results demonstrate that the pyridine,pyrazole and pyrimidine rings are nearly coplanar,which is evident from the dihedral angles among the four rings in the range of 0.13～4.15o.The face-to-face π-π stacking interactions among pyridine,pyrazol and pyrimidine rings result in a supramolecular crystal,in which they seem to be effective in stabilizing the structure.Meanwhile,the fluorescence properties of the title compound were discussed,which showed very strong fluorescence.The calculated results（selected bond lengths,bond angles and torsion angles） are all typical and agree well with the experimental results,which demonstrates that B3LYP/6-31＋G＊ is suitable for the title compound.

Preparation of Nanosized AlOOH and Its Application in Polymer-inorganic Nanocomposites

With industrial grade Al（OH）3 as raw materials, the self dispersion nanosized AlOOH crystal powder were prepared by the sol-hydrothermal method. The results of XRD and TEM show that the nanosized AlOOH could automatically disperse to a single-dispersing state in water without surface modification, dispersant, additive and accessional conditions （ultrasonic wave dispersing, ball-mill dispersing）. The application results of the product indicate that the nanosized AlOOH can be composed into a toughened nanocomposites without surface modification. Accordingly, the self dispersion characteristic and mechanism of hydrothermal crystallization and charging composite dispersion of nanosized AIOOH are found, and a new technique of preparing polymer/inorganic nanocomposites is proposed, which is called blending compositing new techniques of sol even dispersing at auasi-homogeneous phase.

Investigation of in situ Growth of SrMoO_4 Nanoplates by Microcalorimetry

SrMoO4 nanoplates were synthesized by a facile reverse microemulsion method at room temperature.Energy evolution of this in situ growth process was monitored by means of a microcalorimeter.A sharp exothermic peak for the initial reaction and two discontinuous relatively weak exothermic peaks for the subsequent crystal growth emerged on the microcalorimetric heat flow curve.Based on the in situ thermokinetic data,the rate constants of the nucleation process and crystallization process at 298.15 K were calculated to be 4.078×10-3 and 5.033×10-4 s-1,respectively.The growth mechanism and energy evolution were investigated.

Fe_3O_4 Magnetic Nanoparticles Modified Electrode as a Sensor for Determination of Nimesulide

A novel type of Fe3O4 nanoparticles modified glass carbon electrode（Fe3O4/GCE） was constructed and the electrochemical properties of N-（4-nitro-2-phenoxyphenyl）methanesulfonamide（nimesulide） were studied on the Fe3O4/GCE.In 0.4mol/L HAc-NaAc buffer solution（pH=5.0）,the electrode process of nimesulide was irreversible at bare GCE and Fe3O4/GCE.The Fe3O4/GCE exhibited a remarkable catalytic and enhancement effect on the reduction of nimesulide.The reduction peak potential of nimesulide shifted positively from-0.683 V at bare GCE to-0.625 V at Fe3O4/GCE,and the sensitivity was increased by ca.3 times.Some experimental conditions were optimized.The linear range between the peak current and the concentration of nimesulide was 2.6×10-6 ＂1.0×10-4mol/L（R=0.993） with a detection limit of 1.3×10-7mol/L.This method has been used to determine the content of nimesulide in medical tablets.The recovery was determined to be 96.9% ＂101.9% by means of standard addition method.The method is comparable to UV-Vis spectrometry.

Amperometric Hydrogen Peroxide Biosensor Based on Multiwall Carbon Nanotubes and Cadmium Sulfide Quantum Dots

A novel third-generation hydrogen peroxide（H2O2） biosensor（Hb/CdS/MWNTs/GCE） was fabricated through hemoglobin（Hb） adsorbed onto the mercaptoacetic acid modified CdS QDs/carboxyl multiwall carbon nanotubes＇（MWNTs） films. Cyclic voltammogram of Hb/CdS/MWNTs/GCE showed a pair of well-defined and quasi-reversible redox peaks with a formal potential（E^0） of-0.230 V（vs. Ag/AgCl） in 0.1 mol/L pH=8.0 phosphate buffer solution（PBS）, which was the characteristic of the Hb heme Fe（Ⅲ）/Fe（Ⅱ） redox couple. The biosensor shows an excellent electrocatalytic activity to the reduction of H2O2. The response time of the designed biosensor to H202 at a potential of-0.30 V was less than 2 s and linear relationships were obtained in the concentration ranges of 2.0×10^-6-2.7×10^-3 mol/L and 2.7×10^-3-7.7×10^-3 mol/L with a detection limit of 3.0×10^-7 mol/L（S/N=3）. The apparent Michaelis-Menten constant Km was estimated to be 1.324 mmol/L that illustrated the excellent biological activity of the fixed Hb.

Highly Stereoselective Synthesis of 1,2-Diorganothio-l-alkenes via Hydrothiolation of Alkynyl Sulfides Catalyzed by Cesium Hydroxide

In the presence of catalytic amount of cesium hydroxide, the hydrothiolation of alkynyl sulfides occurred at room temperature in DMF under nitrogen atmosphere to afford exclusive （Z）-1,2-diorganothio-1-alkene in excellent yields. It could provide a new and expedient way for the preparation of symmetrical and unsymmetrical （Z）-1,2-diorganolthiol-1-alkenes.