纳米SiO_2负载Preyssler杂多酸催化剂对水杨酸与苄醇或脂肪醇酯化反应的催化性能(英文)

An efficient and environmentally benign procedure for the catalytic esterification of salicylic acid with aliphatic alcohols, CnH2n+1OH(n=1-5)and benzylic alcohols,RC6H4CH2OH(R=H,NO2,OCH3,Br,Cl,Me)was developed using nano-SiO2-supported Preyssler heteropolyacid both under thermal conditions and microwave irradiation.Silica nanostructures were obtained through a sol-gel method and were characterized by transmission electron microscopy and powder X-ray diffraction.The effects of various parameters such as solvent type,molar ratio of substrates,Preyssler heteropolyacid loading on silica,catalyst amount,temperature,and reaction time were studied and the optimum conditions were obtained.It has been found that the catalyst with 30 wt%loading is highly active and shows high yields in esterification reactions.The use of nano-SiO2-supported Preyssler heteropolyacid coupled with microwave irradiation allows a solvent-free,rapid(3 min),and high-yielding reaction.This catalyst can be easily recovered and reused for many times without a significant loss in its activity.

A Novel Three-dimensional Inorganic Open-framework Constructed from [Mo_4O_(16)]_n ^(8n-) Chains Linked through Ag^+

A novel 3-D inorganic bimetallic compound Ag2Mo2O7 has been hydrothermally synthesized and structurally characterized by X-ray diffraction. The compound crystallizes in monoclinic, space group P21/c with a = 6.1274（3）, b = 13.1836（6）, c = 7.8780（3）A, β= 110.673（3）°, V = 595.42（5）A3, Z= 4, Mr= 519.62, Dc = 5.797g/cm^3, F（000） = 936,μ（MoKα） = 10.579 mm^-1, F（000） = 936, the final R = 0.0204 and wR = 0.0477 for 1268 observed reflections with I〉 2σ（I）. In the title compound, the [Mo4O16]n^8n-chains are linked through O-Ag-O bridging bonds to form a 3D network. It represents an unprecedented linking mode between the isopolyoxomolybdate chain and the transition metal oxide cluster. IR, TGA and fluorescence properties of the title compound are also studied.

Crystal formation and growth mechanism of inorganic nanomaterials in sonochemical syntheses

A clear understanding of the nucleation, growth, coarsening, the preparation of highly controlled nanostructures. Among and aggregation processes of nanomaterials is necessary to enable wet chemical synthetic methods, ultrasound-assisted preparation has become an important tool in material science. The formation and crystal growth mechanism under ultrasound is special compared with other wet chemical synthetic routes. In this review, we discussed the chemical and physical effect of ultrasound and summarized the ultrasonic effect on crystallization. The sonolysis of water and the cavitation-induced microjet impact and shockwave are the two key factors in the sonochemieal formation of inorganic nanomaterials. The ultrasonic-assisted Ostwald ripening and oriented attachment processes have been reviewed for the possible crystal growth mechanisms in the fabrication of inorganic nanostructures.

Synthesis and Characterization of [Cp2Ln（μ-η1：η2-OC（SR）=CPh2）]2 （R=Bn, Ph and Ln=Yb, Er, Y）

[Cp2Ln（μ-SR）]2 was reacted with Ph2C=C=O to yield ketene mono-insertion products [Cp2Ln（μ-η1：η2-OC（SR）=CPh2）]2 [R=Bn, Ln=Yb （1）, Er （2）, Y （3） and R--Ph, Ln=Yb （4）], indicating that the reactions of organolanthanide thiolates with ketenes are independent of the nature of the thiolate ligand and the ketene as well as the reaction condition. These reactions could provide an efficient method for the synthesis of organolanthanide complexes with the a-thiolate-substituted enolate ligand. All these complexes were characterized by elemental analysis and spectroscopic properties and the structure of complex 1 was determined through X-ray single crystal diffraction analysis.

An Effective Synthesis of Indazolo[2,1-a]indazole-6,12-diones by Regioselective Copper-Catalyzed Cascade Acylation/Coupling Cyclization Process

A new and efficient cascade synthesis of indazolo[2,1-a]indazole-6,12-diones has been developed. This protocol includes an intermolecular N-acylation followed by a copper-catalyzed intramolecular C--N coupling reaction. The methodology is applied to a wide range of 2-bromo and 2-chloro benzoyl chlorides to yield the indazolo- [2,1-a]indazole-6,l 2-diones in good to excellent yields with high regioselectivities.