Study on anion electrochemical recognition based on a novel ferrocenyl compound with multiple binding sites

A novel ferrocenyl anion receptor N, N, N, N-(dimethyl, ethyl, ferrocenecarboxylic amidodimethylene) ammonium fluoborate 2 with multiple binding sites was synthesized. Its anion recognition behaviors were investigated by CV, 1H NMR and UV-vis spectrum. It was found that the combination of two interactions enforced the anion binding ability and the binding selectivity of 2 to phosphate anion. The effects of scan rate on the CV curves of 2 with phosphate were also investigated. In different scan rate, the CV curves kept stable which indicated the strong binding between 2 and phosphate. According to relationships of peak potential, peak currents and scan rate of 2 binding with phosphate, the kinetic parameters of electrode process such as diffusion coefficient Dapp, surface transfer coefficient alphan alpha, and standard rate constant k0 were calculated.     

Towards the rational synthesis of norfullerenes. controlled deletion of one carbon atom from C60 and preparation of 2,5,9-trioxo-1-nor(C60-Ih)[5,6]fullerene C59(O)3 derivatives

Norfullerenes are fullerene-like compounds (fulleroids) resulting from partial deletion of fullerene skeleton carbons. The one carbon less norfullerene C59(O) 3 derivatives having three carbonyl groups on the rim of the orifice are prepared through peroxide-mediated reactions. A key step involves a novel PCl 5 initiated rearrangement of a hydroxyl amine adduct. Decarboxylation serves as the carbon removal step.     

Molecular wires based on thienylethynylene: synthesis, photophysical properties, and excited-state lifetime

A series of pi-conjugated molecular wires based on thienylethynylene units have been developed to understand the effect of the molecular structures on their photophysical properties. The investigation of their photophysical properties indicates that the formation of aggregates at the ground state is effectively suppressed by the incorporation of truxene units. The excited-state lifetimes are observed to be biexponential for these molecular wires.     

In-situ construction of Co(OH)2 nanoparticles decorated biochar for highly efficient degradation of tetracycline hydrochloride via peracetic acid activation

Peracetic acid(CH₃C(O)OOH, PAA)-based heterogeneous advanced oxidation process(AOP) has attacked intensive interests due to production of various reactive species. Herein, Co(OH)₂ nanoparticles decorated biochar(Co(OH)2_/BC) was fabricated by a simple and controllable method, which was used to degrade tetracycline hydrochloride(TTCH) in water through PAA activation. The results indicated that 100% TTCH(C0= 10 μmol/L) degradation efficiency was realized within 7 mi...     

Determination of total flavonoids in Scutellaria barbata D. Don by dynamic ultrasonic extraction coupled with on-line spectrophotometry

A dynamic ultrasonic extraction (DUE) coupled with on-line detection by spectrophotometry is proposed for the determination of total flavonoids (calculated against scutellarin) in Scutellaria barbata D. Don. The extraction was performed in a common self-made extraction vessel put in an ultrasonic bath and a peristaltic pump was used to deliver the extraction solvent. Several experimental parameters of DUE, including flow rate and concentration of extraction solvent, ultrasonic power and sample amount, were optimized. In this work an on-line method was provided with the advantages of minimum sample amount (5 mg), on-line monitoring the extraction process and time saving (12.5 min). Compared with off-line method, the proposed method would be more convenient for obtaining continuous measurements and rapid optimization of the extraction process.     

Qualitative and quantitative analysis of Swertia herbs by high performance liquid chromatography-diode array detector-mass spectrometry (HPLC-DAD-MS)

We evaluated the composition of Swertia herbs using high performance liquid chromatography-diode array detector-mass spectrometry (HPLC-DAD-MS). Eleven peaks of 6 species were unequivocally identified by comparing their retention times, UV spectra, on-line electrospray ionization mass (ESI-MS) spectra, and collision-induced dissociation mass spectrometry/mass spectrometry (CID-MS/MS) data with those of authentic compounds. We adopted wavelengths of 254 nm, 340 nm and 230 nm to simultaneously determine these 11 compounds. By comparing the overall DAD and total ion current (TIC) profiles of various samples, the 6 species were differentiated in terms of the occurrence and/or relative concentrations of the eleven compounds. Our novel validated HPLC-DAD-MS method not only facilitates quality control and identification of Swertia herbs, but is also applicable to systematic investigations of the distribution of secoiridoids, flavonoids, and xanthones in the genus Swertia.     

An excellent single-layered photoreceptor composed of oxotitanium phthalocyanine nanoparticles and an insulating resin

Photoconductive oxotitanium phthalocyanine (TiOPc) nanoparticles with an average diameter of 3.6 nm were successfully prepared. These nanoparticles could be well dispersed in organic solvents such as 1,2-dichloroethane to form a stable organic sol of solvent-stabilized TiOPc nanoparticles. An obvious size effect of TiOPc semiconductor was revealed by the UV-vis absorption spectroscopy measurements. Single-layered photoreceptors were prepared by coating colloidal solutions containing the C(2)H(4)Cl(2)-stabilized TiOPc nanoparticles and a polycarbonate (PC) resin onto aluminum plates. Optimum xerographic properties of the present photoreceptors were obtained on a photoreceptor containing 20 wt% of the TiOPc nanoparticles, which exhibited a photoconductive sensitivity (E(1/2)) of 0.54 microJ/cm(2) and could be positively charged to 596 V.     

Rational combination of two privileged chiral backbones: highly efficient organocatalysts for asymmetric direct aldol reactions between aromatic aldehydes and acylic ketones

A new class of organocatalysts has been designed by rational combination of proline with cinchona alkaloids. The chiral amine 3a, prepared from l-proline and cinchonidine, has been found to be an efficient catalyst for the direct aldol reactions of acetone or 2-butanone with a wide range of aldehydes (up to 98% ee). The cinchonidine backbone is essential to the reaction efficiency and enantioselectivity.     

Ring-opening reactions of difluoro(methylene)cyclopropanes with halogens and amines

The distal and proximal bond of difluoro(methylene)cyclopropanes (F2MCPs) could be cleaved, respectively, under different conditions to give the corresponding ring-opening products. The reaction mechanisms are discussed.     

Quaternary ammonium chitosan derivative dynamic coating for the separation of veterinary sulfonamide residues by CE with field-amplified sample injection

A quaternary ammonium chitosan, 2-hydroxypropyltrimethylammonium chloride chitosan (HACC), has been developed for the dynamic coating material in CE for the first time. It presented many advantages such as favorable water solubility, satisfactory coating efficiency, and EOF toward the anode at pH >7.0. Using the modified fused-silica capillary, sulfonamides (SAs), an important group of veterinary drugs, were separated and detected by CE combined with field-amplified sample injection (FASI). The LODs of sulfonamides with UV detection were less than 0.5 ng/mL. The proposed method has been applied to the determination of veterinary sulfonamide residues in samples such as chicken, beef, and honey with fast separation (15 sulfonamides within 20 min), low LODs (0.1-0.5 ng/mL), and good reliability compared to the criteria of China (GB/T 18932.17-2003).