Direct observation of p,p′‐dimercaptoazobenzene produced from p‐aminothiophenol and p‐nitrothiophenol on Cu2O nanoparticles by surface‐enhanced Raman spectroscopy

Surface‐enhanced Raman scattering of p‐aminothiophenol and p‐nitrothiophenol were obtained on the surface of Cu₂O nanoparticles, showing novel spectral changes with morphology‐dependent and time‐dependent characteristics. The measured Raman signals were believed to partly originate from the newly produced surface species p,p′‐dimercaptoazobenzene. The nature of surface chemisorption status during Raman measurement was investigated experimentally and theoretically via combined surface‐enhanced Raman scattering and density functional theory study, indicating that surface catalytic reaction of p‐aminothiophenol and p‐nitrothiophenol could take place on the surface of oxide nanostructures as well as coinage metal material. Copyright © 2013 John Wiley & Sons, Ltd.     

Aggregation and supramolecular membrane interactions that influence anion transport in tryptophan-containing synthetic peptides

Self-assembly is a desired property in supramolecular chemistry, but extensive aggregation may be counterproductive. Rigid systems typically have better organization, but are inherently less dynamic. This work shows that ion transport by amphiphilic heptapeptides (synthetic anion transporters or SATs) is affected by aggregation of the monomers in the bulk aqueous phase to which they are added and within the bilayer. Ion transport was assessed for all compounds by assay of Cl(-) release from liposomes. The mechanism of ion transport was confirmed by planar bilayer conductance studies for two compounds at opposite ends of the efficacy scale. Dynamic light scattering, the Langmuir trough, transmission electron microscopy, ion release from liposomes, and planar bilayer conductance studies were used to assess the importance of self-assembly versus aggregation in ion transport. Generally, greater aggregation was has an adverse effect on the transport, although at least dimerization is required for amphiphilic heptapeptides to readily transport Cl(-). Anion transport in these systems was found to be sensitive to changes in the C-terminal portion of the (Gly)(3)Pro(Gly)(3) sequence. Moreover, a significant difference in transport efficacy was apparent when L-Trp was replaced by D-Trp in the same position.     

Intramolecular alkene electrophilic bromination initiated ipso-bromocyclization for the synthesis of functionalized azaspirocyclohexadienones

Intramolecular alkene electrophilic bromination initiated dearomative cyclization has been realized in the presence of DBDMH to provide functionalized azaspirocyclohexadienones in excellent yields under mild conditions.     

A novel sensitive turn-on fluorescent Zn2+ chemosensor based on an easy to prepare C3-symmetric Schiff-base derivative in 100% aqueous solution

A C(3)-symmetric Schiff-base example of the new simple, low cost, highly water soluble, and sensitive turn-on fluorescent Zn(2+) chemosensor is described. The sensor was successfully applied to the detection of intracellular Zn(2+). Moreover, the sensor could also serve as a potential recyclable component in sensing materials. Notably, the color change is so obvious that all of the recycling process can be seen clearly by the naked eye.     

Organocatalyzed enantioselective formal [4 + 2] cycloaddition of 2,3-disubstituted indole and methyl vinyl ketone

A formal [4 + 2] cycloaddition of 2,3-disubstituted indoles with vinyl methyl ketone was realized in the presence of a catalytic amount of quinine-derived primary amine and pentafluorobenzoic acid. This method provides bridged-ring indoline scaffolds containing two quaternary carbon centers with excellent yields and enantioselectivity (up to 98% yield and 98% ee).     

The synthesis, self-assembly and electrocatalytic property of a novel disulphide derivatised cobalt(II) deuteroporphyrin

A novel disulphide derivatised deuteroporphyrin 2,7,12,18-tetramethyl-13,17-(propionylaminoethyldithioethyl amino-formy-lethyl) -29,34-bis-(methoxyformyl)porphyrin(PDTEP,3) and its cobalt(Ⅱ) complex(Co(II)PDTEP,4) were conveniently synthesized. The disulphide functional group of 4 allowed its stable immobilization on gold electrodes.The modified electrode was characterized by IR and confirmed electrochemically and showed good stability and catalytic activity toward the electro-catalyzed reduction of hydrogen peroxide.