Efficient oxidation of benzylic alcohols with [hydroxy(tosyloxy)iodo]benzene under microwave irradiation

An efficient method for the oxidation of benzylic alcohols with [hydroxy(tosyloxy)iodo]benzene under solvent-free microwave irradiation conditions is described.     

Fabrication of solid thin film electrolyte and LiCoO2 by aerosol flame pyrolysis deposition

Aerosol flame pyrolysis deposition method was applied to deposit the oxide glass electrolyte film and LiCoO₂ cathode for thin film type Li-ion secondary battery. The thicknesses of as-deposited porous LiCoO₂ and Li₂O–B₂O₃–P₂O₅ electrolyte film were about 6 μm and 15 μm, respectively. The deposited LiCoO₂ was sintered for 2 min at 700 °C to make partially densified cathode layer, and the deposited Li₂O–P₂O₅–B₂O₃ glass film completely densified by the sintering at 700 °C for 1 h. After solid state sintering process the thicknesses were reduced to approximately 4 μm and 6 μm, respectively. The cathode and electrolyte layers were deposited by continuous deposition process and integrated into a layer by co-sintering. It was demonstrated that Aerosol flame deposition is one of the good candidates for the fabrication of thin film battery.     

Carbohydrate chips for studying high-throughput carbohydrate-protein interactions

Carbohydrate-protein interactions play important biological roles in living organisms. For the most part, biophysical and biochemical methods have been used for studying these biomolecular interactions. Less attention has been given to the development of high-throughput methods to elucidate recognition events between carbohydrates and proteins. In the current effort to develop a novel high-throughput tool for monitoring carbohydrate-protein interactions, we prepared carbohydrate microarrays by immobilizing maleimide-linked carbohydrates on thiol-derivatized glass slides and carried out lectin binding experiments by using these microarrays. The results showed that carbohydrates with different structural features selectively bound to the corresponding lectins with relative binding affinities that correlated with those obtained from solution-based assays. In addition, binding affinities of lectins to carbohydrates were also quantitatively analyzed by determining IC(50) values of soluble carbohydrates with the carbohydrate microarrays. To fabricate carbohydrate chips that contained more diverse carbohydrate probes, solution-phase parallel and enzymatic glycosylations were performed. Three model disaccharides were in parallel synthesized in solution-phase and used as carbohydrate probes for the fabrication of carbohydrate chips. Three enzymatic glycosylations on glass slides were consecutively performed to generate carbohydrate microarrays that contained the complex oligosaccharide, sialyl Le(x). Overall, these works demonstrated that carbohydrate chips could be efficiently prepared by covalent immobilization of maleimide-linked carbohydrates on the thiol-coated glass slides and applied for the high-throughput analyses of carbohydrate-protein interactions.     

Phase separation behavior of epoxy resin modified with crosslinked rubber

Low molecular weight liquid rubber (ATBN = amine terminated butadiene acrylonitrile copolymer or CTBN = carboxyl terminated butadiene acrylonitrile copolymer)–DGEBA (diglycidyl ether of bisphenol A) blends indicated upper critical solution temperature (UCST) behavior. The phase separation behavior of the neat and crosslinked rubber (ATBN, CTBN)–epoxy blends was analyzed by a laser light scattering experiment. Lauryl peroxide (LPO) was employed to crosslink the rubber during the initial annealing stage. The onset point of the phase separation in the crosslinked ATBN–epoxy system occurred later than in the case of the neat ATBN–epoxy system. However, the onset point of the phase separation process started earlier in the case of the crosslinked CTBN–epoxy system. The domain correlation length of the crosslinked rubber-added system was smaller than that of the neat rubber-added system.     

Interpretation of structure formation during the sol-gel transition of a resorcinol-formaldehyde solution by population balance

Growth of colloidal particles formed during the sol-gel transition of a resorcinol-formaldehyde (RF) solution was simulated based on the population balance equation by using the discrete-sectional model (DSM). During the early stage of the sol-gel transition, the transient change of sizes of colloidal particles estimated by this method agreed well with the previous experimental observation by dynamic light scattering (DLS), which confirmed the influence of the catalyst concentration of a starting RF solution on the growth rate of the particles. From the size distribution of colloidal particles predicted at the gelation time, the surface area of a RF hydrogel after the completion of the sol-gel transition was estimated, which coincided with the BET surface area of a RF aerogel because the porous structure of a hydrogel was maintained and few micropores were formed during supercritical drying.     

The participation of the anion and alkyl substituent of diaryliodonium salts in photo‐initiated cationic polymerization reactions

The photo‐initiated cationic polymerization (PCP) of epoxides using diaryliodonium salt photoacid generators (PAGs) bearing alkyl groups and anions was investigated. The properties and reactivities of a series of iodonium salts containing various cations and anions were compared in the context of a PCP reaction. The products from the decomposition of the cations of these salts were analyzed using gas chromatography‐mass spectrometry (GC‐MS) spectra. The relationship between the molecular structure of the salts and their reaction mechanism in the PCP reaction was investigated. Based on the results of the investigation, it was concluded that the structures of the cations and anions of theiodonium salts affect the PCP reaction rate, which was controlled by the products from the diaryliodonium salts. As part of an additional investigation, the diaryliodonium salts‐epoxide materials were applied to 254 nm‐photo‐patterning. Copyright © 2006 John Wiley & Sons, Ltd.     

Irreversible and Reversible Deactivation of Bilirubin Oxidase by Urate

Oxygen is electroreduced to water on a carbon cathode coated with wired bilirubin oxidase in a pH 7.4 0.15 M NaCl phosphate buffer solution at 37 °C at much lesser polarization than it is on a pure platinum cathode in 0.5 M H₂SO₄. While the wired bilirubin oxidase cathode operates for over a week in the aerated or oxygenated buffer solution, it is degraded rapidly when in serum. We reported earlier that in the presence of O₂ an intermediate product of the electrooxidation of urate, which is a normal serum component, irreversibly damages the wired bilirubin oxidase and also reported that the electrocatalyst is irreversibly damaged, in the absence of urate, when it is brought, by disconnecting the electrode, to the O₂/H₂O half cell potential at pH 7.4. Here we report that a) dissolved bilirubin oxidase is irreversibly and rapidly damaged by urate in the presence of O₂; and b) that the immobilized wired bilirubin oxidase electrocatalyst is not only irreversibly deactivated by urate in the presence of O₂ in a few hours, but is initially reversibly deactivated, in 1 min or less, by the urate in the presence of O₂.     

Studies on the Complexes of N,N′-Bis[o-(diphenylphosphino)benzylidene]ethylenediamine with Transition Metal Ions

The thermodynamic parameters for the interaction of Cu²⁺, Ni²⁺, Co²⁺, Cd²⁺, andAg⁺ with the new title ligand have been determined by titration calorimetry in 50% THF–methanol (V/V) at 25 °C.Ag⁺ exhibited remarkably higher complexation selectivity.Ag⁺ and several transition metal ions have been transportedusing this ligand as carrier in a bulk liquid membrane. CompetitiveAg⁺–M²⁺ transport studies have also beencarried out for the same system. In this membrane transport study, high transport of Ag⁺ was observed in both single and competitiveAg⁺–M²⁺ transport studies. The complexformation of N,N-bis[o-(diphenylphosphino)benzylidene]ethylenediamine (P₂N₂) with silver,[Ag(P₂N₂)] (NO₃), (1) is reported. Complex 1 has been characterized by X-ray crystallography. 1 ismonoclinic, space group P2_1/n (No. 14), with cell dimensionsa = 13.398(4) , b=12.577(5) , c = 21.521(4) , =100.14(2) , V = 3570(2) ³ and Z = 4.     

Cyclic vinylogous triflate hemiacetals as new surrogates for alkynyl aldehydes

Cyclic vinylogous triflate hemiacetals can serve as ‘synthetic equivalents’ for alkynyl aldehydes: treatment of a vinylogous triflate hemiacetal with excess amounts of Grignard reagents produces acyclic alkynyl alcohols in good to high yields. This transformation likely involves the Grob-type C-C bond cleaving fragmentation to form the alkynyl aldehyde in situ. Subsequent nucleophilic attack of the Grignard reagent furnishes secondary alkynols. Vinylogous triflate hemiacetals are easily prepared by DIBALH reduction of vinylogous acyl triflates, which are derived from cyclic 1,3-diketones.     

Selective Recognition of Calcium Ion through Liquid Membrane

The mole transport rate of alkaline earth metal ions through a bulk liquid membrane and a supported liquid membrane using a series of proton diionizable acyclic polyethers was measured. Among alkaline earth metal ions, the calcium ion was observed to be selectively transported in both single and competitive transport experiments. Potentiometric titration and solution calorimetric titration also gave calcium selectivity over other alkaline earth metal ions. Acyclic polyether bearing a diethylene glycol unit andn-tetradecyl lipophilic chain at the α position of carboxylic acid affords the best selectivity for the calcium ion in bulk and supported liquid membranes.