In this communication, we report the synthesis of small‐sized (<10 nm), water‐soluble, magnetic nanoparticles (MNPs) coated with polyhedral oligomeric silsesquioxanes (POSS), which contain either polyethylene glycol (PEG) or octa(tetramethylammonium) (OctaTMA) as functional groups. The POSS‐coated MNPs exhibit superparamagnetic behavior with saturation magnetic moments (51–53 emu g?1) comparable to silica‐coated MNPs. They also provide good colloidal stability at different pH and salt concentrations, and low cytotoxicity to MCF‐7 human breast epithelial cells. The relaxivity data and magnetic resonance (MR) phantom images demonstrate the potential application of these MNPs in bioimaging. 相似文献
We herein report the efficient syntheses of 4-(hetero)aryl-substituted 1-chlorophthalazines via heteroarylation of arenes/heteroarenes through AlCl(3)-induced C[bond]C formation reactions. A number of (hetero)arenes were reacted with 1,4-dichlorophthalazine to give aryl/heteroaryl-substituted phthalazines in good to excellent yields. Many of them were converted to the corresponding phthalazin-1(2H)-ones. 相似文献
Plasmonic noble metal nanostructures have been targeted due to their strong surface plasmon resonance at photoelectrochemical interfaces. Recently, it has been concluded that, the plasmonic noble metal nanostructures on photoexcitation permit the transfer of effective hot carriers (hot electron/hole pair) to nearby adsorbed molecules where, the transformed hot carriers can efficiently decrease the activation barrier of a reaction. In this review, our recent achievements in the plasmon-mediated chemical reactions of organic molecules such as para-aminothiophenol, substituted para-aminothiophenol and para-nitrothiophenol at nanostructures modified noble metal electrodes using surface enhanced Raman spectroscopy, electrochemical methods, and theoretical calculations will be discussed. 相似文献
The authors describe an electrochemical approach for the preparation of a glassy carbon electrode (GCE) modified with graphene oxide and silver nanodentrites (AgNDs). The coating was obtained by using an aqueous solution containing silver nitrate, phosphate and ammonia. The phosphate anions act as a scaffold for the improved deposition of AgNDs. The effects of deposition potential and time and concentration of electrolyte on the formation of the AgNDs were optimized. The modified GCE displays good electrocatalytic activity towards the oxidation of dissolved hydrazine. The electron transfer coefficient and diffusion coefficient are 0.60 and 4.64 × 10?5 cm2 s?1 respectively. The electrode exhibits a linear response over the 100 nM to 670 μM hydrazine concentration range and a detection limit (LOD) of 33 nM. The sensitivity of the modified electrode is 2077 μA mM?1 cm?2 at a typical working voltage of 0.1 V (vs Ag/AgCl). This LOD is much lower than that of the allowable concentration of hydrazine in drinking water as defined by the US EPA and the WHO.
Graphical abstract Schematic of the 2-step fabrication of a glassy carbon electrode (GCE) modified with graphene oxide (GO) and silver nanodendrites (AgND) for use in a hydrazine sensor. First, Ag3PO4 is formed by adding AgNO3 and phosphate. Secondly, the formed Ag3PO4 is converted to a colorless complex by adding ammonia and by electrolytic growth of AgND on the GO/GCE.
Enzyme from Daucus carota root catalyzed Henry reaction of substituted benzaldehydes and nitromethane in phosphate buffer of pH 7 at 28?°C to afford β-nitroalcohols in excellent yields (up to 94%). 相似文献
3,3'-Bipyrroles 3 could be synthesized using a double Michael addition reaction involving diaroyl acetylene 1 and the appropriate 1,3-dicarbonyls 2 using ammonium acetate as a nitrogen source. The axial chirality of bipyrrole was anticipated from the X-ray crystal structure and DFT calculations and confirmed by separating the racemates on a chiral column and subsequent CD spectra of the enantiomers. The absolute configuration of the enantiomers was achieved by theoretical CD spectra calculation using the ZINDO method. 相似文献
3-Acetyl-1,6,7,12b-tetrahydroindolo[2,3-a]quinolizin-2(12H)-one, C17H16N2O2, consists of two symmetry-independent molecules and each forms a layered structure stabilized by N—H⃛O and C—H⃛O hydrogen bonds. In 3-acetyl-6,7-dihydroindolo[2,3-a]quinolizin-4(12H)-one monohydrate, C17H14N2O2·H2O, the structure is stabilized by O—H⃛O, N—H⃛O and C—H⃛O hydrogen bonds, with the ordered water molecule playing a crucial role in the self-assembly. Contribution from the weak interactions to the strong hydrogen-bonded network is a common feature in both structures. 相似文献
(S)-Prolinol facilitated the coupling reaction of terminal alkynes with 3-iodoflavone under palladium-copper catalysis in aqueous DMF affording a mild and convenient method for the synthesis of 3-alkynyl substituted flavones of potential biological interest. 相似文献
Chemoselective reductions of alkenes, α,β-unsaturated carbonyl compounds, nitro and nitroso compounds, N,N-hydrogenolysis of azo and hydrazo functions as well as simultaneous reduction and hydrodehalogenation of substituted aryl halides, including bulkier substrates, were achieved by catalytic transfer hydrogenation (CTH) using mesoporous PdMCM-41 catalyst. The yields were practically unaffected upon recycling of the catalyst. Further, the CTH process is accomplished without affecting the reduction of any other reducible functional group. 相似文献