Design, Synthesis and Optical Response of Pyridine-Cored V-Shaped Stilbenoid Dendrimers
作者:Debabrata Jana、Binay K. Ghorai
DOI:10.2174/157017810791112522
日期:2010.4.1
Design, synthesis and characterization of new series of first-generation V-shaped dendrimers bearing phenylenevinylene dendritic branches in periphery and pyridine as a core is described. A preliminary study of the optical properties of the resulting compounds was conducted by UV/vis and fluorescence spectroscopy.
Microwave-assisted synthesis of palladium nanoparticles supported on graphene: A highly active and recyclable catalyst for carbon–carbon cross-coupling reactions
作者:Ali R. Siamaki、Abd El Rahman S. Khder、Victor Abdelsayed、M. Samy El-Shall、B. Frank Gupton
DOI:10.1016/j.jcat.2010.12.003
日期:2011.4
Pd nanoparticles supported on graphene (Pd/G) by microwave-assisted chemical reduction of the corresponding aqueous mixture of a palladium salt and dispersed graphite oxide (GO) sheets. The Pd/G demonstrated excellent catalytic activity for the carbon–carbon cross-coupling reactions (Suzuki, and Heck) with a broad range of utility under ligand-free ambient conditions in an environmentally friendly
Highly efficient and magnetically recyclable graphene-supported Pd/Fe3O4 nanoparticle catalysts for Suzuki and Heck cross-coupling reactions
作者:Hany A. Elazab、Ali R. Siamaki、Sherif Moussa、B. Frank Gupton、M. Samy El-Shall
DOI:10.1016/j.apcata.2014.11.033
日期:2015.2
reaction conditions with an extremely high turnover number (TON) of 9250 and turn over frequency (TOF) of 111,000 h−1 at 80 °C. The magnetic properties imparted by the Fe3O4 component of the catalyst enables the catalyst to be easily isolated and recycled, thus greatly simplifying the ability to purify the reaction products and increasing the economic value of the catalyst. The utility of these magnetic
本文中,我们报告了一种简便高效的一步法合成负载在石墨烯纳米片上的高活性Pd / Fe 3 O 4纳米颗粒(Pd / Fe 3 O 4/ G)表现出对Suzuki和Heck偶联反应极好的催化活性,并且可以从反应混合物中磁性分离并多次循环使用,而不会损失催化活性。合成方法是基于微波(MW)在水合肼作为还原剂的氧化石墨烯(GO)纳米片存在下,钯和硝酸铁的还原。通过比较四种具有不同性能的不同催化剂的催化活性和可回收性,结果为系统变量提供了基本的了解。最具活性和可回收性的催化剂包含7.6 wt%的Pd纳米颗粒,其Pd(0)氧化态的直径为4-6 nm,并与30 wt%的Fe 3 O 4充分分散在高度还原的GO上具有12–16 nm直径的纳米粒子,其C / O比为8.1。在MW反应条件下,这些综合性质为Suzuki交叉偶联反应产生了显着的催化活性,在80°C下的极高周转率(TON)为9250,转换频率(TOF)为111
Luminescent rhenium(I) complexes of substituted imidazole[4,5-f]-1,10-phenanthroline derivatives
作者:R. Owen Bonello、Ian R. Morgan、Benjamin R. Yeo、Lucy E.J. Jones、Benson M. Kariuki、Ian A. Fallis、Simon J.A. Pope
DOI:10.1016/j.jorganchem.2013.08.031
日期:2014.1
Seven new chromophoric ligands (L1–L7), based upon the fused imidazo[4,5-f]-1,10-phenanthroline core, were dually functionalised with a variety of aryl substituents of varying character, and can be synthesised utilising a one-pot methodology. The resultant ligands are fluorescent (λem = 408–425 nm) and amenable to further reactivity with pentacarbonylbromorhenium to give coordination complexes of the
基于稠合的咪唑并[4,5 - f ] -1,10-菲咯啉核,七个新的发色配体(L1 - L7)被双官能化,并带有各种不同性质的芳基取代基,并且可以利用一个锅法。将所得的配位体是荧光(λ EM = 408-425纳米)和适于用pentacarbonylbromorhenium进一步反应,得到形式的配位络合物FAC - [ReBr(CO)3(NN)](其中NN = L1 - L7)。已使用多种光谱和分析技术对复合物进行了充分表征,并使用X射线衍射研究对三个实例进行了结构确认。这些新的rh络合物都是发光的,在充气溶液中显示出经典的3 MLCT发射。配合物表明,3 MLCT激发态对螯合的咪唑并[4,5 - f ] -1,10-菲咯啉配体的官能化性质中等敏感。
Photocatalysis by 3,6-Disubstituted-<i>s</i>-Tetrazine: Visible-Light Driven Metal-Free Green Synthesis of 2-Substituted Benzimidazole and Benzothiazole
作者:Suvendu Samanta、Sudipto Das、Papu Biswas
DOI:10.1021/jo401445j
日期:2013.11.15
s-Tetrazine based molecules were prepared for visible-light-driven organic transformations. The 3,6-di(pyridin-2-yl)-1,2,4,5-tetrazine (pytz) derivative shows visible light absorption and reversible one-electron reduction behavior. In the presence of pytz and aerial oxygen, aldehyde reacts with o-phenylenediamine or o-aminothiophenol under visible light irradiation at ambient temperature to produce corresponding 2-substituted benzimidazoles and benzothiazoles, respectively. Pytz catalyst demonstrates excellent catalytic activity for alkyl, aryl, organo-metallic substituted aldehydes and reducing sugar. The reaction yield is high for both the electron-donating and electron withdrawing substituents in aromatic aldehydes. The use of a metal-free catalyst and visible light energy, along with the mild reaction conditions, makes this reaction an environmentally benign and energy-saving chemical process.