[N′-(3-Meth­oxy-2-oxidobenzyl­idene)nicotinohydrazidato]dimethyl­tin(IV)

In the title complex, [Sn(CH3)2(C14H11N3O3)], the Sn atom is in a distorted trigonal-bipyramidal coordination, with Sn—O distances of 2.138 (2) and 2.176 (2) Å. The dihedral angles between the two chelated benzene rings and the O—Sn—N group are 71.73 (9) and 83.30 (9)°

Preparation of Mesoporous V2O5@TiO2 Composites with Enhanced Photoactivity for Gaseous Benzene Degradation

AbstractMesoporous V2O5@TiO2 composites were fabricated by an ultrasonic method with V2O5 sol as the guest precursor. The prepared materials were characterized by powder X-ray diffraction, field emission-scanning electron microscopy, transmission electron microscope, X-ray photoelectron spectroscopy, UV-Vis spectroscopy and nitrogen sorption analysis. The results indicated that V2O5 nanoparticles dispersed well on/into the porous structure of TiO2 matrix. The composites presented typical IUPAC IV isotherms with type H2 hysteresis loops, revealing the mesoporous structure. It was observed that V2O5 loading led to red shift of the absorption edge to 540nm and reduced the band gap < 3.0eV. The V2O5@TiO2 composites with V/Ti molar ratio of 0.1 exhibited outstanding degradation efficiency of gaseous benzene

An easy two-step microwave assisted synthesis of SnO2/CNT hybrids

Tin oxide (SnO2) - decorated carbon nanotube (CNT) heterostructures were synthesized by microwave assisted wet impregnation method. CNTs of three different aspect ratios were compared. The hybrid samples were characterized by powder X-ray diffraction, Raman spectroscopy, high resolution transmission electron microscopy, BET surface area analysis and DC conductivity measurement. The results showed that the microwave assisted synthesis is a very efficient method in producing CNTs that are heavily decorated by SnO2 nanoparticles in a very short time (total reaction time of 10 min.), irrespective of their length and diameter. The hybrids showed 100 times increase in electrical conductivity when compared to the unmodified CNTs

Side-by-Side In(OH)3 and In2O3 Nanotubes: Synthesis and Optical Properties

A simple and mild wet-chemical approach was developed for the synthesis of one-dimensional (1D) In(OH)3 nanostructures. By calcining the 1D In(OH)3 nanocrystals in air at 250 °C, 1D In2O3 nanocrystals with the same morphology were obtained. TEM results show that both 1D In(OH)3 and 1D In2O3 are composed of uniform nanotube bundles. SAED and XRD patterns indicate that 1D In(OH)3 and 1D In2O3 nanostructures are single crystalline and possess the same bcc crystalline structure as the bulk In(OH)3 and In2O3, respectively. TGA/DTA analyses of the precursor In(OH)3 and the final product In2O3 confirm the existence of CTAB molecules, and its content is about 6%. The optical absorption band edge of 1D In2O3 exhibits an evident blueshift with respect to that of the commercial In2O3 powders, which is caused by the increasing energy gap resulted from decreasing the grain size. A relatively strong and broad purple-blue emission band centered at 440 nm was observed in the room temperature PL spectrum of 1D In2O3 nanotube bundles, which was mainly attributed to the existence of the oxygen vacancies

Preparation of Ag@PDA@SiO2 electrospinning nanofibrous membranes for direct bacteria SERS detection and antimicrobial activities

In this paper, a convenient method to fabricate flexible and free-standing surface-enhanced Raman scatting (SERS) substrates for direct bacteria detection without aptamer bonding is presented. SiO _2 nanofibers were prepared via electrospinning and calcination by using tetraethyl orthosilicate as the precursor. Subsequently, it was coated with polydopamine (PDA) by self-polymerization. Finally, Ag@PDA@SiO _2 nanofibrous membranes were obtained through in situ growth of Ag nanoparticles in Tollens’ reagents. The as-prepared Ag@PDA@SiO _2 composite nanofibrous membranes were characterized by techniques of scanning electron microscopy, transmission electron microscopy, X-ray powder diffraction, energy-dispersive x-ray spectroscopy and thermo gravimetric analysis. The flexibility of the as-prepared nanofibrous membranes were verified simply through manual folding. Small molecule probes of 4-mercaptophenol (4-MPh) and 4-mercaptobenzoic acid (4-MBA) were chosen to investigate the SERS sensitivity of the as-prepared Ag@PDA@SiO _2 as free-standing substrates. Furthermore, Escherichia coli ( E. coli ) and Staphylococcus aureus ( S. aureus ), as typical strains of Gram-negative and Gram-positive bacteria, were performed to directly SERS detection by dropping bacteria suspension onto the fibrous membranes without any previous treatment, such as aptamer combination. In addition, the antimicrobial properties of the as-prepared Ag@PDA@SiO _2 electrospinning nanofibrous membranes were tested by inhibition zone and turbidity methods. The results show that Ag nanoparticles with an average diameter of 50 nm are uniformly deposited on the surface of electrospinning nanofibers, and the as-prepared Ag@PDA@SiO _2 nanofibrous membranes are flexible. As SERS substrates, it shows a rather high detection limitation of 10 ^−11 mol l ^−1 for 4-MPh and 4-MBA. More importantly, this substrate can be applied for bacteria label-free SERS detection, i.e., complicated procedures are avoided. Meanwihile, the as-prepared Ag@PDA@SiO _2 nanofibrous membranes exhibit excellent antibacterial properties. Thus, it has application prospects in trace bacteria detection and water purification

Interference effects in the sum frequency generation spectra of thin organic films. I. Theoretical modeling and simulation

A general theoretical calculation is described for predicting the interference effect in the sum frequency generation (SFG) spectra from a model thin-film system as a function of film thickness. The calculations were carried out for a three-layer thin film consisting of an organic monolayer, a dielectric thin film of variable thickness, and a gold substrate. This system comprises two sources of SFG, namely, a resonant contribution from the monolayer/dielectric film interface and a nonresonant contribution from the dielectric film/gold interface. The calculation shows that both the spectral intensity and the shape of the SFG spectra vary significantly with the thickness of the dielectric layer due to interference effects in the thin film. The intensity changes at a particular frequency were explained in terms of the changes in the local field factors (L factors) as a function of the dielectric film thickness. The L factor for each beam changes periodically with the thickness of the dielectric film. However, the combined L factor for the three beams shows complicated thickness dependent features and no clear periodicity was found. On the other hand, if the susceptibilities of both the resonant and nonresonant terms are fixed, changes in the spectral shape will be mainly due to changes in the phase differences between the two terms with the film thickness. The interference behavior also depends strongly on the polarization combinations of the sum frequency, visible, and infrared beams. A general method is provided for predicting changes in the spectral shapes at different film thicknesses by taking into account the relative intensities and phases of the SFG signals from the two interfaces. The model calculation provides important insights for understanding the nonlinear optical responses from any thin-film system and is an essential tool for quantitatively revealing the nonlinear susceptibilities, which are directly related to the actual structure of the interfacial molecules from the observed SFG spectra after quantitative removal of the L factors

Mussel-Inspired Fabrication of PDA@PAN Electrospun Nanofibrous Membrane for Oil-in-Water Emulsion Separation

Emulsified oily wastewater threatens human health seriously, and traditional technologies are unable to separate emulsion containing small sized oil droplets. Currently, oil–water emulsions are usually separated by special wettability membranes, and researchers are devoted to developing membranes with excellent antifouling performance and high permeability. Herein, a novel, simple and low-cost method has been proposed for the separation of emulsion containing surfactants. Polyacrylonitrile (PAN) nanofibers were prepared via electrospinning and then coated by polydopamine (PDA) by using self-polymerization reactions in aqueous solutions. The morphology, structure and oil-in-water emulsion separation properties of the as-prepared PDA@PAN nanofibrous membrane were tested. The results show that PDA@PAN nanofibrous membrane has superhydrophilicity and almost no adhesion to crude oil in water, which exhibits excellent oil–water separation ability. The permeability and separation efficiency of n-hexane/water emulsion are up to 1570 Lm−2 h−1 bar−1 and 96.1%, respectively. Furthermore, after 10 cycles of separation, the permeability and separation efficiency values do not decrease significantly, indicating its good recycling performance. This research develops a new method for preparing oil–water separation membrane, which can be used for efficient oil-in-water emulsion separation