Charge-Transfer Interactions of Aluminum Copper(I) Chloride with Polystyrene and Related Compounds

Interactions between polystyrene and aluminum copper(I) chloride (AlCuCl₄) were investigated by various spectroscopic measurements in order to elucidate the structure of polystyrene-AlCuCl₄ complex in solution and the mechanism of water resistance of the complex as a carbon monoxide absorbent. The chemical shift (101 ppm) and half line width (145 Hz) of AlCuCl₄ in benzene by ²⁷Al-NMR suggest a dimer structure bridged by two chlorine atoms, which is almost identical with that of aluminum chloride. The coordination of benzene or other aromatic compounds to AlCuCl₄ was confirmed by charge-transfer bands in UV and visible absorptions. The equilibrium constants (K) for complex formation of AlCuCl₄ with various aromatic compounds were determined by ¹³C-NMR spectroscopy. In the case of AlCuCl₄ and benzene in 1,2-dichloroethane, for example, K is 2.2 M ^?1 at 303 K. For the polymer complex solution and 1,3-diphenyl-propane solution, strong charge-transfer bands have been observed in the wavelength region at about 380 to 500 nm, where no band is observed in benzene derivatives. This strong charge-transfer band is considered to be due to the strong interaction of AlCuCl₄ with adjacent aromatic rings of polystyrene or 1,3-diphenylpropane of a chelate type, which, as a result, causes the water resistance of the present carbon monoxide absorbent system.     

Polymerized Micelle-Protected Platinum Clusters. Preparation and Application to Catalyst for Visible Light-Induced Hydrogen Generation

Platinum clusters protected by polymerized micelles were prepared by radical polymerization of unsaturated surfactants which were involved in micelle-protected platinum clusters. The micelle-protected platinum clusters were successfully prepared by photoreduction of hexachloroplatinic acid in water in the presence of unsaturated surfactants. The platinum clusters thus obtained were characterized by electron microscopy and IR and ¹H-NMR spectroscopies. The average diameter of the platinum particles was about 1 nm by electron microscopy, and the polymerization was confirmed by IR and ¹H-NMR spectra. The platinum clusters thus obtained proved to be highly active catalysts for visible light-induced hydrogen generation in the system of EDTA/Ru(bpy)₃ ²⁺/MV²⁺. The polymerized micelle-protected platinum clusters showed higher catalytic activity than the linear polymer-protected one. The catalytic activity was affected by the electric charge of the surfactants in the polymerized micelle-protected platinum clusters. Nonionic polymers were superior to those having anionic and cationic hydrophilic groups from the viewpoint of catalytic activity. The nonionic polymerized micelle forms rigid hydrophobic cores which help charge separation and the formation of a sequential potential field.     

Laser-enabled Auger decay in rare-gas atoms

In rare-gas atoms, Auger decay in which an inner-valence shell ns hole is filled is not energetically allowed. However, in the presence of a strong laser field, a new laser-enabled Auger decay channel can open up to increase the double-ionization yield. This process is efficient at high laser intensities, where an ns hole can be filled within a few femtoseconds of its creation. This novel laser-enabled Auger decay process is of fundamental importance for controlling electron dynamics in atoms, molecules, and materials.     

Preparation and characterization of Co–Pt bimetallic magnetic nanoparticles

CoPt₃ nanoparticles are synthesized by a two-stage route using NaBH₄ as a reductant. The nanoparticles are characterized by thermogravimetry (TG) and differential thermal analysis (DTA), Fourier transform infrared (FT-IR), transmission electron microscopy (TEM) and X-ray diffraction (XRD). Structural and spectroscopic studies show that the nanoparticles adopt a face-centered-cubic (FCC) crystalline structure with an average particle size of 2.6 nm. SQUID studies reveal that as-synthesized nanoparticles are superparamagnetic at room temperature and ferromagnetic at 1.85 K with coercivity of 980 Oe. Annealing of the samples at 500 °C causes an increase of particle size and a decrease of coercivity.     

Thermal transporting properties of electrically conductive polyaniline films as organic thermoelectric materials

Thermal transporting properties of electrically conductive polyaniline films were first investigated in wide range of temperatures above room temperature as organic thermoelectric materials. Thermal conductivities of various protonic acid-doped polyaniline films were measured by combination of a laser flash method and a differential scanning calorimeter in relation with electrical conductivity and a kind of dopant. The thermal conductivities thus measured are in the range of conventional organic polymers, indicating that the doped polyaniline films have extremely low thermal conductivities among electrically conductive materials, and have correlation with neither electrical conductivity, nor a kind of dopant. Consequently the polyaniline film, which shows very high electrical conductivity, has comparable thermoelectric figure-of-merit (ZT) with feasible inorganic thermoelectric materials such as iron silicide. This revised version was published online in August 2006 with corrections to the Cover Date.     

Electrogenerated chemiluminescence with solvated electrons in hexamethylphosphoroamide (HMPA)

The electrogenerated chemiluminescence of N-toluenesulfonyl carbazole, 9-chlorofluorene derivatives and N,N,N′,N′-tetramethyl-p-phenylenediamine (TMPD) with solvated electrons in HMPA are discussed. The fairly bright emissions occurred simultaneously when solvated electrons were generated electrochemically. In the case of N-toluenesulfonyl carbazole and 9-chlorofluorene derivatives, the respective carbanions formed by “dissociative electron transfer reactions” are the fluorescents. The singlet state of TMPD seems to be directly formed by the electron transfer reactions between radical cations of TMPD and solvated electrons.     

Photodegradation of lipopolysaccharides and the inhibition of macrophage activation by anthraquinone-boronic acid hybrids

Target-selective photodegradation of 3-deoxy-D-manno-2-octulopyranosonic acid (KDO) was achieved without additives and under neutral conditions using a designed anthraquinone-boronic acid hybrid and long wavelength UV light irradiation. The hybrid can photodegrade lipopolysaccharides (LPS) and inhibit macrophage activation induced by LPS.     

Degradation of Target Oligosaccharides by Anthraquinone–Lectin Hybrids with Light Switching

Anthraquinone–lectin hybrids were effectively synthesized using water‐soluble anthraquinone derivative 11 with concanavalin A (ConA) and hygrophorus russula lectin (HRL) to give anthraquinone–ConA ( 16 ) and anthraquinone–HRL ( 17 ) hybrids, respectively. These anthraquinone–lectin hybrids effectively and selectively degraded oligosaccharides containing a mannose residue as a non‐reducing terminal sugar, which has affinity for ConA and HRL, under photo‐irradiation with long‐wavelength UV light without additives and under neutral conditions. In addition, anthraquinone–HRL ( 17 ) selectively photo‐degraded only Man(α1,6)Man, which has a high affinity for HRL, among several mannosides by recognition of both the type and glycosidic linkage profile of the sugar in an oligosaccharide.