Stabilisation of gold nanoparticles by N-heterocyclic thiones
作者:Leonardo C. Moraes、Bertrand Lacroix、Rute C. Figueiredo、Patricia Lara、Javier Rojo、Salvador Conejero
DOI:10.1039/c7dt01856h
日期:——
Gold nanoparticles (Au-NPs) have been prepared using N-heterocyclic thiones (NHTs) as ligand stabilisers. These Au-NPs have been shown to be very stable, even in air, and have been characterized by a combination of several techniques (TEM, HR-TEM, STEM-HAADF, EDX, DLS, elemental analysis and 1H NMR). These nanoparticles are active in the catalytic reduction of nitroarenes to anilines.
金纳米颗粒(Au-NPs)已使用N-杂环硫酮(NHTs)作为配体稳定剂制备。这些Au-NP甚至在空气中也显示出非常稳定的特性,并且已通过多种技术(TEM,HR-TEM,STEM-HAADF,EDX,DLS,元素分析和1 H NMR)的组合进行了表征。这些纳米颗粒在将硝基芳烃催化还原成苯胺中具有活性。
Synthesis of Azobenzenes Using <i>N</i>-Chlorosuccinimide and 1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU)
作者:Alford Antoine John、Qing Lin
DOI:10.1021/acs.joc.7b01530
日期:2017.9.15
A convenient method for the synthesis of symmetrical azobenzenes is reported. This one-step procedure involves treatment of anilines with N-chlorosuccinimide (NCS) and organic base 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU). A wide range of commercially available substituted anilines readily participate in this reaction to produce the corresponding azobenzenes in moderate-to-excellent yields in minutes
Controlling the type of indium salt and hydrosilane enables a highly selective reduction of aromatic nitro compounds into three coupling compounds, azoxybenzenes, azobenzenes and diphenylhydrazines, and one reductive compound, anilines.
We demonstrated how a reduction step with a reducing system comprised of In(OTf)3 and Et3SiH and a subsequent oxidation that occurred under an ambient (oxygen) atmosphere allowed the highly selective and catalytic conversion of aromatic nitrocompounds into symmetrical or unsymmetrical azobenzene derivatives. This catalytic system displayed a tolerance for the functional groups on a benzene ring: an
The transformation of nitrobenzenes into azobenzenes by pyridine-derived super electron donor 2 is described. This method provides an efficient synthesis of azobenzenes because of not requiring the use of expensive transition-metals, toxic or flammable reagents, or harsh conditions. Moreover, when using 2-fluoronitrobenzenes as substrates, phenazines were found to be obtained. The process affords a