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Highly efficient particulate matter (PM) filter membranes with good resistance to wetting are highly desirable given the negative environmental impact of increasing PM pollution. In this study, a self-cleaning and PM-filtering fibrous membrane (F-SAPAN) was prepared by attaching silica nanoparticles (SiNPs) on the surface of modified polyacrylonitrile using a sol–gel approach and then adding a low surface energy 1H,1H,2H,2H-perfluorodecyltrichlorosilane (FOTS) coating. The SiNPs were generated by the hydrolysis of tetraethyl orthosilicate and could be readily loaded on the surface of the fiber, thanks to hydrogen bonding. In this way, fibrous membranes with a uniform covering of SiNPs could be prepared in large quantities in a short time. The modification of SiNPs by FOTS endows the fibrous membrane with excellent water and oil resistance (a water contact angle of up to 156° and an oil contact angle of up to 144°), and the free-rolling of water droplets can be achieved on a slope of only 6°. The membrane is only 0.03 mm thick and displays excellent filtration efficiency (>99.9%) and pressure drop (366.4 Pa) for PM1. The membranes also display good flexibility, mechanical properties, corrosion resistance, and antiash properties and prove to be a reliable material for PM filtration in complex environments. [ABSTRACT FROM AUTHOR]

The preparation and characterization of Pt nanoelectrodes in the range of 1 to 3 nm in radii are reported. APt microwire is sealed into a bilayer quartz capillary and pulled into an ultrasharp Pt nanowire sealed in a silica tip using a laser-assisted pulling process. The ultrasharp tip is then sealed into a piece of glass tubing, which is manually polished to expose the Pt. Transmission electron microscopy and steady-state voltammetry are utilized to characterize the nanoelectrodes. The results show that the minimum size of the Pt nanoelectrode is determined by the size of the Pt microwire and parameters used in the pulling process. The heterogeneous electron transfer rate constant for the oxidation of ferrocene, ferrocenemethanol, and potassium hexachloroiridate (III) are determined from steady-state voltammetry using the method of Mirkin and Bard and are found to be [k.sup.o] = 7.6 [+ or -] 3.4 cm/s and = 0.85 [+ or -] 0.06 for ferrocene, [k.sup.o] = 7.4 [+ or -] 6.9 cm/s and = 0.78 [+ or -] 0.16 for ferrocenemethanol, and [k.sup.o] = 6.0 [+ or -] 4.2 cm/s and [alpha] = 0.72 [+ or -] 0.15 for Ir[[Cl.sub.6.sup.3-].

This paper reports the size-exclusion properties of nanoporous films derived from polystyrene--poly(methylmethacrylate) diblock copolymers (PS-b-PMMA) for biomacromolecules. These properties were assessed by measuring cyclic voltammetry of ferritin (12 nm in diameter) adsorbed onto recessed nanodisk-array gold electrodes (RNEs) fabricated from the nanoporous films having different effective pore diameters and surface functionalities. RNEs having 20-nm-diameter nanopores modified with a poly(ethylene glycol) (PEG) layer showed the redox currents of ferritin after their immersion in a ferritin solution (5 mg/mL) for longer than 2 h. The currents originated from the direct electron transfer reaction of ferritin molecules immobilized on the underlying gold surface as a result of their penetration through the 20nm-diameter nanopores. The PEG modification of the nanopore surface was required for the penetration of ferritin, probably because it reduced the nonspecific adsorption of ferritin to the nanopore surface. In contrast, no redox current of ferritin was observed for RNEs having PEG-modified 15-nm-diameter nanopores after their immersion in the ferritin solution for 12 h, indicating the size-exclusion of ferritin from the 15-nm nanopores. The distinct size-exclusion properties of the PS-b-PMMA-derived nanoporous films reflect their uniform diameters and shapes and will provide a means for fabricating separation membranes for biomolecules with high size-based selectivity.

With the development of modern infrared detection systems, military targets are more easily exposed, leading to the increasing risk of high-value targets being detected. Thus, stealth materials are highly desired to protect these targets. Additionally, stealth materials should expand their application scenarios to meet the growing performance requirements of military equipment. In this work, a polyacrylonitrile (PAN)/Al–ZnO/Ag nanofiber composite (PAN/ZAO/Ag) with three functions including infrared protection, antibacterial property, and self-cleaning was prepared by electrospinning, solvothermal, and electroless plating processes. The Schottky junction was formed due to the direct contact between ZAO nanosheets and Ag nanoparticles, leading the materials to possess the characteristic of plasmon resonance absorption of near-infrared light. In the thermal infrared imaging band of 8–14 μm, the infrared emissivity of the fiber was as low as 0.39, effectively blocking the target's thermal radiation. The composite membranes also achieved self-cleaning effect and synergistic antibacterial effect, with the maximum contact angle of 131.5° for water and 100% of antibacterial rate. In summary, this study provided a possibility for multifunctional infrared protective clothing materials to deal with the complex battlefield environment. [ABSTRACT FROM AUTHOR]

Research has been conducted on chiral auziliary (+/-)-N,N-dimethyl-1-(2,5-di,ethylphenyl)ethylamine complex. The authors describe the design and synthesis of the complex carried out from 1-acetyl-2,5-dimethylbenzene.

In the presence of a catalytic amount of heavier tetrylene dichlorides, an allenic diborene 1 undergoes a 1,3-hydrogen shift to afford a terminal diborene 2, which can be deemed a boron analogue of vinylidene dication stabilized by Lewis bases. X-ray diffraction analysis and computational studies revealed that 2 involves a conjugative interaction between the C= C and B=B π-orbitals. The reaction of 2 with ZnBr[sub 2]afforded the corresponding isolable complex 3, in which two boon centers coordinate to the Zn atom asymmetrically. [ABSTRACT FROM AUTHOR]

1-Phenyl-2-vinyl-3,4-dimethylphosphole(4) was prepared from the corresponding 2-carboxaldehydevia a Wittig reaction. The reaction of its P-W(CO)5complex 5with [PhP-W(CO)5] selectively takes place atthe vinyl double bond and gives the corresponding phosphirane 6as a mixture of two diastereomers. The reaction of 4with N-phenylmaleimide involves the phospholedienic system and gives the [4 + 2] 7-phosphanorbornene cycloadduct 7. The reaction of 5with dimethyl acetylenedicarboxylateeither takes place at the phosphole dienic system and leads to thevinyl phthalate 10with loss of the phosphorus bridgeor involves the double bonds of the vinyl and one phosphole groupto give the [4 + 2] cycloadduct 9, which is oxidizedin situ to give 11with two epoxides and one ketone functionality.The products 6, 7, 9, and 11were characterized by X-ray crystal structure analysis. [ABSTRACT FROM AUTHOR]

Thereaction of 1-phenyl-2-lithio-3,4-dimethylphosphole with W(CO)6at −90 °C followed by methyl triflate at roomtemperature gives the complex [(phosphol-2-yl)methoxycarbene]pentacarbonyltungsten(1). This complex reacts with sulfur to give the correspondingcomplex [methyl (phosphol-2-yl)thiocarboxylate]pentacarbonyltungsten(2), in which tungsten has migrated from the carbeneto phosphorus. The reaction of 3with alkynes at 90 °Cgives the corresponding phospholene-annelated cyclopentenones 5without the need for a nickel catalyst. In one case, anintermediate vinylketene rearranges by an intramolecular Diels–Alderreaction to give the tricyclic compound 6. All of theproducts have been characterized by X-ray crystal structure analysis. [ABSTRACT FROM AUTHOR]