A novel colorimetric and fluorescent sensor for fluoride detection based on a three-arm phenanthroline derivative

A novel highly sensitive colorimetric receptor trisphen for F^? ion based on three-arm phenthroline derevative trisphen had been successfully designed, synthesized, and characterized. Experiments showed that receptor trisphen could selectively recognize the F^? and AcO^? in DMSO and even in competitive hydrogen-bonding mixture solutions. The ability of recognition and the bond between trisphen and anions were determined using naked eye, UV–vis, and fluorescence analyses. Benesi–Hildebrand equation indicated that receptor trisphen associated with F^? and AcO^? in a 1:2 stoichiometry. Moreover, ¹H NMR experiments were carried out to explore the insight of interaction between trishen and anions. To the best of our knowledge, this is the first example of anion sensor based on three-arm phenanthroline derivative.     

咪唑基改性的水溶性PDI荧光材料的合成和表征及对Cu2+离子的荧光检测

以3,4,9,10-苝四甲酸二酐为原料合成了水溶性荧光材料-N,N'-二(1-氨丙基-3-丙基咪唑盐)-3,4,9,10-苝四羧酸二酰亚胺(PDI),引入的咪唑基团使PDI不仅溶于DMSO、DMF等有机溶剂,可溶于EtOH/H2O、Acetone/H2O、THF/H2O等的混合溶液,不仅提高了PDI在有机相和有机相/水相的溶解性,同时扩展了PDI的适用范围.对比不同的混合溶剂发现,PDI在EtOH/H2O中的荧光较强,UV-Vis最大吸收波长和荧光最大发射波长分别为526nm和540nm.进而在EtOH/H2O溶剂中,比较了PDI对各种离子的荧光识别作用,其中PDI作为Cu2+的荧光探针时,受干扰小,选择性较高.TG结果表明,PDI拥有高的热稳定性,温度达353℃时质量损失仅为5％.     

一种新型含三苯胺二苯乙烯衍生物的合成及性能研究

合成了一种新型的空穴传输材料三苯胺二苯乙烯衍生物DPAVBi,并通过一系列手段对其进行了表征。DPAVBi具有较好的无定形成膜性及较高的热稳定性。以DPAVBi为电荷传输层,TiOPc为光生层制备的双层光电导体,其光敏性在762nm处达到1.67cm2·μJ-1,是一种优良的空穴传输材料。     

Synthesis and gas sensing properties of novel SnO2 nanorods

We report the microstructures and gas sensing properties of two novel SnO₂ nanorods prepared by hydrothermal method with the utilizing of cetyltrimethylammonium bromide and polyethylene glycol. The structures and morphologies of the dense and porous nanorods were characterized by means of powder X-ray diffraction and scanning electron microscopy. The gas sensing performances towards ethanol of the two samples were investigated. The results show that the porous SnO₂ nanorods display excellent gas response to ethanol, indicating SnO₂ as a potential gas sensing material for broad applications.     

Synthesis of a novel water-soluble chitosan derivative for flocculated decolorization

To increase the water solubility and cationic charges at pH 7, cationic moieties were introduced onto both the C(6)-OH and C(2)-NH(2) groups in the chitosan (CTS) matrix by graft modification. The chemical structure of the obtained copolymer was demonstrated by characterizations of FT-IR, (13)C NMR, WXRD, SEM. Its excellent decolorization properties as a novel flocculant were evaluated with the C.I. Reactive Orange 5 (RO 5) and C.I. Reactive Blue 19 (RB 19) solutions using a jar test method. Both the nature of the anionic dyes and the pH of the initial dye solutions had effects on the decolorization properties. Charge neutralization played a dominant role for the color removal at pH 4, while polymer bridging contributed mainly to the color removal at pH 7. For the given flocculant/dye solutions, added salt was not in favor of the flocculated decolorization. At 25 °C, the flocculant needed for the highest color removal at pH 4 was 60 wt% of the dye (RO 5 or RB 19), but that at pH 7 were 100 wt% of RB 19 and 120 wt% of RO 5, respectively.     

Nano-structure of polyimide and poly(isobutyl methacrylate) monolayer films studied by interlayer electron transfer between porphyrin and pyromellitic diimide moieties

Hetero-multilayers composed of porphyrin-containing poly(isobutyl methacrylate) (PiBMA) and polyimide (PI) monolayers were prepared by using the Langmuir-Blodgett technique, and the interlayer electron transfer process from photo-excited porphyrins to pyromellitic diimide moieties in PI layers was observed by fluorescence spectroscopy. The efficiency of the electron transfer showed strong dependence on the number of PI layers, suggesting the presence of defects in the PI plane, which were filled with PI after the successive deposition of PI monolayers. The three-dimensional and two-dimensional active sphere models (Perrin model) well explained the interlayer electron transfer phenomena. We discussed the nano-structures of the multilayer films in terms of the thickness of each layer and the location of hydrophobic porphyrins in the PiBMA monolayer.     

Paper-based vapor detection of hydrogen peroxide: colorimetric sensing with tunable interface

Vapor detection of hydrogen peroxide still remains challenging for conventional sensing techniques, though such vapor detection implies important applications in various practical areas, including locating IEDs. We report herein a new colorimetric sensor system that can detect hydrogen peroxide vapor down to parts per billion level. The sensory materials are based on the cellulose microfibril network of paper towels, which provide a tunable interface for modification with Ti(IV) oxo complexes for binding and reacting with H(2)O(2). The Ti(IV)-peroxide bond thus formed turns the complex from colorless to bright yellow with an absorption maximum around 400 nm. Such complexation-induced color change is exclusively selective for hydrogen peroxide, with no color change observed in the presence of water, oxygen, common organic reagents or other chelating reagents. This paper-based sensor material is disposable and one-time use, representing a cheap, simple approach to detect peroxide vapors. The reported sensor system also proves the technical feasibility of developing enhanced colorimetric sensing using nanofibril materials that will provide plenty of room to enlarge the surface area (by shrinking the fiber size), so as to enhance the surface interaction with gas phase.     

一种具有光学特性的新型哌嗪衍生物晶体的合成与表征

以哌嗪（PQ）和马来酸酐（MAH）为原料,在较温和的条件下制备了一种新型哌嗪衍生物-4,4’-（1,4-哌嗪基）-2-（4-羰基-2-丁烯酸）,简称为PBBA。采用倒置相差显微镜、傅里叶红外吸收光谱（FT-IR）、高效液相色谱质谱联用仪（HPLC-EMS）、高精度原子力扫描电镜（AFM-IPC）等对其性能和结构进行了表征。结果表明PBBA晶体具有特异的光学性能和对称的分子结构。     

Synthesis,characterization, electrical and sensing properties of ZnO nanoparticles

The present study investigates the electrical and sensing properties of mechanically compacted pellets of nanosized zinc oxide powders synthesized by chemical method at room temperature in alcohol base using Triethanolamine (TEA) as capping agent. Synthesized ZnO particles has been characterized for its optical, structural, morphological properties using UV–VIS spectrophotometer, X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). The ZnO particles have hexagonal wurtzite structure and the particles are of 20–30 nm in size. The electrical properties of the prepared material have been investigated with Impedance Spectroscopy at different temperatures and frequencies and other laboratory setup. Resistivity, I–V curves, AC impedance of ZnO nanoparticles pellets with temperature was investigated and response was compared with commercial ZnO. Piezoelectric and oxygen sensing property of ZnO were also examined. Dynamic hysteresis of sintered ZnO pellet using axis ACCT TF analyzer 2000HS did not show polarization retention by sample. Oxygen sensing of ZnO pellet has been investigated for different concentrations of oxygen for the temperature range of 200–350 °C. The decrease of the current flow through the ZnO pellet with increasing oxygen concentration indicates the application of ZnO in oxygen sensing. The prepared ZnO particles were also used for preparing nanofluids of different concentrations and were characterized by measuring thermal conductivity using hot wire method which shows sigmoidal behavior over a temperature range of 10–50 °C.     

Synthesis, characterization and gas sensing property of hydroxyapatite ceramic

Hydroxyapatite (HAp) biomaterial ceramic was synthesized by three different processing routes viz. wet chemical process, microwave irradiation process, and hydrothermal technique. The synthesized ceramic powders were characterized by SEM, XRD, FTIR and XPS techniques. The dielectric measurements were carried out as a function of frequency at room temperature and the preliminary study on CO gas sensing property of hydroxyapatite was investigated. The XRD pattern of the hydroxyapatite biomaterial revealed that hydroxyapatite ceramic has hexagonal structure. The average crystallite size was found to be in the range 31–54 nm. Absorption bands corresponding to phosphate and hydroxyl functional groups, which are characteristic of hydroxyapatite, were confirmed by FTIR. The dielectric constant was found to vary in the range 9–13 at room temperature. Hydroxyapatite can be used as CO gas sensor at an optimum temperature near 125°C. X-ray photoelectron spectroscopic studies showed the Ca/P ratio of 1.63 for the HAp sample prepared by chemical process. The microwave irradiation technique yielded calcium rich HAp whereas calcium deficient HAp was obtained by hydrothermal method.     

1, 5-Bis (2-hydroxyacetophenone)thiocarbohydrazone: A novel colorimetric and fluorescent dual-mode chemosensor for the recognition of fluoride

1,5-Bis (2-hydroxyacetophenone)thiocarbohydrazone (H₄L) has been synthesized and characterized by means of spectroscopic and single crystal X-ray diffraction methods. Interactions of the H₄L with a variety of anions were investigated using a combination of UV–visible and fluorescence spectroscopic methods in a biological competing solvent DMSO. The H₄L has a high degree of selectivity for fluoride over other anions. ¹H NMR titration experiments indicate that a deprotonation process is involved in the chemo sensing process.     

一种l，5-萘二胺衍生物的合成及性能研究

合成了一种纯度较高的l，5-萘二胺衍生物NPN，制备了NPN薄膜。利用紫外/可见吸收光谱和荧光发射光谱研究了NPN的发光行为，并结合电化学循环伏安法研究了其电子能级结构。差热扫描法（DSC）测定其玻璃化温度（Tg）高达129.7℃，熔点达245.7℃。结果表明，NPN薄膜在365nm紫外光的激发下，产生发光峰在448.6nm附近、谱线带宽为72.6nm的蓝光发射，发光亮度高，色纯度高。NPN的HOMO能级为-5.74eV，光学禁带约为2.79eV。NPN具有良好的热稳定性和给电子性，有望成为优良的空穴传输材料，也期望通过设计合理的器件结构实现电致蓝光发射。     

Synthesis and properties of a novel methoxy poly(ethylene glycol)-modified galactosylated chitosan derivative

Chitosan and its derivatives are attractive non-viral vectors. To produce target-cell specificity and improve the solubility of chitosan, a novel chitosan derivative, modified with galactose and methoxy poly(ethylene glycol) (mPEG) was synthesized, and structure changes of chitosan and its derivatives were characterized. Compared to chitosan, the solution viscosity of the novel chitosan derivative drastically decreased. And, the degree of substitution (DS) of chitosan by galactose and mPEG were calculated as 0.09 and 0.30. The average diameter and zeta potential of mPEGylated galactosylated chitosan (GaC) nanoparticle containing VRMFat plasmid were 178 nm and +2.93 mV, suggesting suitable properties for gene delivery system. The gel electrophoresis confirmed that the plasmid DNA was remained completely by the mPEGylated GaC nanoparticle. And, the cytotoxic effect of mPEGylated GaC nanoparticles on human embryonic kidney (HEK 293) cells was negligible in comparison with that of control chitosans. Therefore, it is expected that the mPEGylated GaC will have the potential as a targeting gene delivery system for a further application. Tao Zhang and Dong Li equally contributed to this research.     

A novel method for sensing rotational speed, linear displacement and current using superconducting BPSCCO magnetic sensor

For many decades, magnetic sensors have been of great assistance to mankind in variety of functions that include simple compass based navigational systems to devices that monitor the invisible biological activities. In industries magnetic sensors are in great demand for control and measurement of linear and rotary position sensing etc, because of its non destructive and contact less way of detection. Consequently, newer, smarter and cheaper materials are continuously being explored to suit the varied needs of technological requirements. In the present communication, the characteristics of a magnetic sensor, based on the non linear electromagnetic response of the weak links present in the polycrystalline BPSCCO superconductor are reported. The second harmonic response of sintered superconducting BPSCCO pellet in an alternating magnetic field at 40 kHz and 77 K being a strong linear function of low d.c. magnetic field has been utilized for the development of highly sensitive magnetic field sensors. The noise limited resolution of the sensor is found to be 3.16 ×10^-9 T/√Hz for H_a.c = 16 Oe and frequency 40 kHz. We further demonstrate that such HTSC based magnetic sensors are capable of sensing the rotational speed, small displacement and direct current with good resolution. The experimental methods and results obtained are discussed.     

桥位芳香性给电子基团取代的苝二酰亚胺的合成及其光伏性能

采用Suzuki反应合成出了系列桥位芳香性给电子基团（三苯胺与N-苯基咔唑基团）取代的苝二酰亚胺衍生物2a～2d,并对其光学及电化学性能进行了表征。结果发现桥位经过芳香性给电子基团取代后,苝二酰亚胺的吸收范围拓宽,吸收峰发生红移;同时,其前线轨道能级上升,具有给电子能力。由此,制备了以2a～2d为电子给体的有机太阳能电池,电池具有明显的光伏响应。     

A novel heterogeneous colorimetric and spectrophotometric chemosensor for detection and adsorption of Hg0 and Hg2+

Functionalized mesoporous silica with an immobilized azobenzene-coupled receptor 1 (FMS-1) as heterogeneous "naked-eye" colorimetric and spectrophotometric chemosensor was prepared by sol-gel reaction. The optical sensing ability of FMS-1 was studied by addition of metal ions such as K+, Ca2+, Sr2+, Co2+, Cd2+, Pb2+, Zn2+, Fe3+, Cu2+ and Hg2+ in aqueous solution. Interestingly, upon the addition of Hg2+ in aqueous suspension, FMS-1 resulted in a color change from maroon to red within 10 s. On the other hand, no significant color changes were observed with the other metal ions. These findings confirm that FMS-1 can be useful as a chemosensor for selective detection of Hg2+ over a range of metal ions. Furthermore, the adsorption ability of the FMS-1 was also estimated by measuring the amount of Hg2+ and Hg0 adsorbed on the FMS-1, resulting in 95% for Hg2+ and 75% for Hg0, respectively, suggesting that the FMS-1 is potentially useful as the adsorbent for separation of Hg0 and Hg2+ in chromatography.     

Synthesis, characterization, and application of fluorescence sensing lipobeads for intracellular pH measurements

This paper describes the synthesis and characterization of micrometric phospholipid-coated polystyrene particles, named lipobeads, with pH-sensing capability and their application for intracellular pH measurements in murine macrophages. The phospholipids used to coat the particles are labeled with fluorescein (a pH-sensitive dye) and tetramethylrhodamine (a pH-insensitive dye), which serves as a referencing fluorophore for increased accuracy of the pH measurements. The synthesis of the pH-sensing lipobeads is realized by the covalent attachment of the fluorescent phospholipids to the surface of carboxylated polystyrene particles. The pH dynamic range of the sensing particles is between 5.5 and 7.0 with a sensitivity of 0.1 pH unit. The excitation light intensity is reduced to minimize photobleaching of the fluorescein-phospholipid conjugates. The fluorescent lipobeads are used to measure the pH in single macrophages. The lipobeads are ingested by the macrophages and directed to lysosomes, which are the cellular organelles involved in the phagocytosis process. Despite the high lysosomal levels of digestive enzymes and acidity, the absorbed particles remain stable for over 6 h in the cells when they are stored in a phosphate-buffered saline solution at pH 7.4.     

A mesoporous silica functionalized by a covalently bound pyridine derivative for selective optical sensing of thymidine

Fluorescent receptor 1 immobilized mesoporous silica (FMS) possessing the diaminopyridine moiety as a fluorescent receptor was fabricated by sol-gel reaction. The binding ability of FMS with nuclobases was evaluated by fluorophotometry. Interestingly, among nucleobases, addition of thymidine to a suspension of FMS in water resulted in the largest decrease in fluorescence intensity of diaminopyridine in FMS. These results indicate that FMS recognizes selectively thymidine in nucleobase.     

Synthesis, characterization and humidity sensing properties of Cu-Sr-Al mixed metal oxide composites

Copper-strontium-aluminum mixed metal oxide composites prepared by sol-gel technique was investigated for humidity sensing properties. X-ray diffraction, scanning electron microscopy (SEM), FT-IR spectroscopy and nitrogen adsorption/desorption isotherm at 77 K was employed, respectively, to identify the structural phases, surface morphology, vibrational stretching frequencies and BET surface area of the composites. The composites were prepared with the mole ratios of Cu:Sr as (0.0:1.0, 0.2:0.8, 0.4:06, 0.6:0.4, 0.8:0.2 and 1.0:0.0) keeping the aluminium mole ratio as constant and were labeled as CuSA1, CuSA2, CuSA3, CuSA4, CuSA5 and CuSA6, respectively. The samples sintered at 900 °C for 5 h, were subjected to dc resistance measurements as a function of relative humidity (RH) in the range 5-98% and the results revealed that the sensitivity factor of CuSA5 possessed the highest humidity sensitivity of 42,000 while the pure composite copper aluminate (CuSA1) and strontium aluminate (CuSA6) possessed comparatively low sensitivities 10,000 and 20,000, respectively. The response and recovery characteristics of the composites CuSA1, CuSA5 and CuSA6 were studied.