Structure determination and characterization of two rare-earth molybdenum borate compounds: LnMoBO(6) (Ln = La, Ce)

The structural, optical, and electronic properties of two rare-earth molybdenum borate compounds, LnMoBO(6) (Ln = La, Ce), have been investigated by means of single-crystal X-ray diffraction, elemental analyses, and spectral measurements, as well as calculations of energy band structures, density of states, and optical response functions by the density functional method. The title compounds, which crystallize in monoclinic space group P2(1)/c, possess a similar network of interconnected [Ce(2)(MoO(4))(2)](2+) chains and [BO(2)](-) wavy chains. Novel 1D molybdenum oxide chains are contained in their three-dimensional (3D) networks. The calculated results of crystal energy band structure by the density functional theory (DFT) method show that the solid-state compound LaMoBO(6) is a semiconductor with indirect band gaps.     

Determination of trace chlorine dioxide based on the plasmon resonance scattering of silver nanoparticles

A plasmon resonance scattering (PRS) method for chlorine dioxide is reported based on the oxidization of silver nanoparticles (NPs) by it, in pH 9.1 ammonia-ammonium nitrate buffer solutions. Silver NPs exhibit strong PRS signals at 470nm, and can be oxidized by ClO(2), which results in PRS quenching at 470nm. It was found that the PRS quenching intensity is proportional to the concentration of chlorine dioxide over the range of 0.0011-0.185microg/mL, with a detection limit (3sigma) of 0.00050microg/mL and the correlation coefficient of 0.9995. The method is simple, rapid and cost effective. It was applied to the determination of chlorine dioxide in drinking water, with satisfactory results.     

Electrochemical pesticide sensitivity test using acetylcholinesterase biosensor based on colloidal gold nanoparticle modified sol-gel interface

Based on the change in electrochemical behavior of enzymatic activity induced by pesticide, a novel electrochemical method for investigation of pesticide sensitivity using acetylcholinesterase (AChE) biosensor was developed. The sol-gel-derived silicate network assembling gold nanoparticles (AuNPs-SiSG) provided a biocompatible microenvironment around the enzyme molecule to stabilize its biological activity and prevented them from leaking out of the interface. The composite was characterized using atomic force microscopy and proved to be chemically clean, porous and homogeneous. AuNPs promoted a conductive pathway for electron transfer and improved electrochemical reactions at a lower potential. Typical pesticides such as monocrotophos, methyl parathion and carbaryl were selected for pesticide sensitivity tests. Due to the inhibitions of pesticides, the electrochemical responses of substrate on AChE-sensors decreased greatly. The inhibition curves showed good correspondence with the results by UV spectrophotometry assay. The proposed electrochemical pesticide sensitivity test exhibited high sensitivity, desirable accuracy, low cost and simplified procedures. This method could be developed as a conventional method to select efficient enzyme inhibitors and investigate toxic compounds against to enzyme.     

Synthesis of soluble oligo- and polymeric pentacene-based materials

Functionalization of pentacene at the 6- and 13-positions affords versatile building blocks for oligomer and polymer formation. Di- and trimeric materials are synthesized using unsymmetrical building block 18, while symmetrical diol monomer 17 allows for the synthesis of polymers. The materials reported herein are soluble in common organic solvents and air-stable. UV-vis and fluorescence spectroscopic properties have been investigated. Solid-state X-ray crystallography of building blocks 17 and 19 shows that these derivatives can π-stack with significant acene face-to-face interactions with spacing of less than 3.5 Å.     

Phenol Inhibition and Restoration of the Bioactivity of Anaerobic Granular Sludge

Inhibition and restoration of different concentrations of phenol on the bioactivity of anaerobic granular sludge were investigated with laboratory-scale equipment. It indicated that phenol concentration lower than 50 mg/l show no inhibitory effect on bioactivities of granular sludge. However, methane productivity, extracellular polymeric substances (EPS) content, and coenzyme F(420) activity were decreased by varying degrees when phenol concentration adopted for inhibition ranged between 50 and 400 mg/l. Noticeably, methane productivity could be fully or partly restored in case the phenol was removed after 24 h of phenol inhibition.     

An analytic solution of capillary rise restrained by gravity

We derive an analytic solution for the capillary rise of liquids in a cylindrical tube or a porous medium in terms of height h as a function of time t. The implicit t(h) solution by Washburn is the basis for these calculations and the Lambert W function is used for its mathematical rearrangement. The original equation is derived out of the 1D momentum conservation equation and features viscous and gravity terms. Thus our h(t) solution, as it includes the gravity term (hydrostatic pressure), enables the calculation of the liquid rise behavior for longer times than the classical Lucas-Washburn equation. Based on the new equation several parameters like the steady state time and the validity of the Lucas-Washburn equation are examined. The results are also discussed in dimensionless form.     

Synthetic studies on Et-743. Assembly of the pentacyclic core and a formal total synthesis

A formal total synthesis of the potent anticancer agent Et-743 is described. The tetrahydroisoquinoline core is stereoselectively constructed using a novel radical cyclization of a glyoxalimine. Further elaboration of this core rapidly accessed the pentacyclic core of Et-743, but a mixture of regiosisomers was obtained in the key Pictet-Spengler ring closure. A known advanced intermediate in the synthesis of Et-743 was intercepted, constituting a formal synthesis of the molecule.     

Synthesis and electrochemical properties of peripheral carbazole functional Ter(9,9-spirobifluorene)s

A facile approach for synthesis of spirobifluorene trimers with peripheral carbazole functional groups by utilizing Suzuki coupling as the key reaction has been developed. These novel compounds exhibit blue emission with high quantum yields in solution and thin films, and excellent spectral stability upon photoirradiation and annealing in air. By the introduction of carbazole groups, the oxidation potentials of spirobifluorene trimers S TCPC-6 and STCPC-4 were significantly lower than that of model compound STHPH without peripheral carbazole groups, which reflect that the title compounds process higher HOMO energy level and better hole-injection ability. Highly luminescent films were obtained by electrochemical coupling between carbazole units. Pure blue-emission single-layer LEDs based on electrochemical deposition films as light emitting layers were achieved.     

Preparation and application of novel polymer nanoparticles in the detection of copper ion and cysteineEI北大核心CSCD

A novel amphiphilic copolymer,dipropenoxystyrene anthracene and acrylic acid copolymer（BASA-AA） was designed and synthesized based on divinyl anthracene. The polymer self-assembled rapidly in water to create polymer nanoparticles（BASA-AA NPs）with a uniform size of 45 nm,no dye leakage,and great brightness（Φ= 36%）. Because of the enormous number of carboxyl groups on the surface of the particles,it can disperse extremely well in water,and can be used for the rapid detection of copper ion and cysteine（Cys）in pure water, with the limit of detection of 45 nmol/L. The fluorescent intensity of the nanoparticles will be greatly reduced after the introduction of copper ion,realizing the detection of copper ion with high selectivity and sensitivity. A composite probe made of BASA-AA NPs and copper ion can detect Cys in the range of 0.1-10 µμmol/L,with the detection limit of 84 nmol/L,due to the high binding capacity of the sulfhydryl group and copper ion. The method is simple and rapid in material synthesis and preparation,and shows high selectivity and sensitivity in pure water. © 2023, Youke Publishing Co.,Ltd. All rights reserved.