Hydrogen storage properties of isocyanide-stabilized palladium nanoparticles

Monodispersed palladium nanoparticles protected with n-octyl isocyanide were prepared, and their hydrogen absorption behavior was evaluated. The formation of the nanoparticles has been confirmed by means of 1H NMR and elemental analysis. Fourier transform infrared (FT-IR) showed that three distinct bands (2156, 1964, and 1611 cm(-1)) assigned to mono-, double-, and triple-bridged isocyanide ligands on the palladium surface. The average diameter of the particles was estimated to be 2.1 +/- 0.7 nm from observation by transmission electron microscopy (TEM). X-ray photoelectron spectroscopy (XPS) analysis revealed that the particles contained Pd(0) with little amounts of Pd(II) or Pd(IV), in sharp contrast to the thiol- or phosphine-stabilized palladium nanoparticles. The absorption and desorption of hydrogen were reversible, and the reactions were much faster for the nanoparticles than for the bulk palladium metal, whereas the storage capacity was almost the same, 0.6 wt %.     

Strained polycycles by H5C5x free-radical cascades

[reaction: see text] An H(5)C(5x)-type free-radical chain reaction selectively generates up to three new bonds and three new stereocenters in one pot. This previously unexploited strategy provides a straightforward route to the tricyclic cyclopenta[c]indene skeleton, present in a wide range of pharmacologically active natural products, and can significantly simplify the synthesis of other strained polycyclic structures by sidestepping protection, deprotection, and functional group interconversion steps.     

Effects of particle volume fraction on distortion of particle-arrayed structure during immobilization of colloidal crystals formed by poly(methyl methacrylate)-grafted silica in acetonitrile

Changes of particle array structure with particle volume fraction during immobilization of colloidal crystals, formed by poly(methyl methacrylate)-grafted silica in acetonitrile, were investigated. Immobilization of colloidal crystals formed in acetonitrile was carried out by two-step photo-radical copolymerization of methyl methacrylate and ethylene dimethacrylate to make organogel, followed by solidification after exchanging the solvent with methyl methacrylate. Crystallite size in colloidal crystals formed in acetonitrile was mostly unchanged with particle volume fraction in the range of 0.11–0.18, while the size and number of single crystals decreased during gelation. Disordering in particle array in immobilized colloidal crystals in gel and poly(methyl methacrylate) matrix was observed to decrease with increasing particle volume fraction less than 0.18 due to strong electrostatic repulsion between particles.     

Luminescent Coordination Polymers Constructed from a Flexible,Tetradentate Diisopyrazole Ligand and Copper(I) Halides

One‐ and two‐dimensional coordination polymers composed of a structurally flexible, tetradentate diisopyrazole ligand and copper(I) halides were synthesized as crystalline solids. Complexation with copper(I) chloride or bromide resulted in the formation of infinite coordination chains through connecting each diisopyrazole ligand with two copper(I) ions in a trigonal planar coordination geometry. Contrarily, the combination of a diisopyrazole ligand and copper(I) iodide gave a two‐dimensional coordination network comprising Cu₄I₄ units with stair‐step type geometry and diisopyrazoles that acted as both tetradentate and bidentate bridging ligands. All the coordination polymers exhibited visible photo‐emission upon UV irradiation, and the Cu₄I₄ complex showed thermochromic behavior.     

Compact Hybrid Subsystem of 16 Channel Optical Demultiplexer, 2x2 Switches, Optical Power Monitors and Control Circuit

A compact hybrid subsystem of 16channel optical demultiplexer, 2x2 switches, optical power monitors and control circuit board is developed. The subsystem is able to add or drop arbitrary optical channels and monitor the optical power level by software commands. The size of the subsystem is 170x200x30(mm).     

Functional microporous materials of metal carboxylate: Gas-occlusion properties and catalytic activities

Copper(II) terephthalate is the first transition metal complex found capable of adsorbing gases. This complex has opened the new field of adsorbent complex chemistry. It is recognized as the lead complex in the construction of microporous complexes. This specific system has been expanded to a systematic series of derivatives of other isomorphous transition metals, molybdenum(II), ruthenium(II, III), and rhodium(II). These complexes with open frameworks are widely recognized as very useful materials for applications to catalysis, separation at molecular level, and gas storage.     

Crystal Structure of Metallo DNA Duplex Containing Consecutive Watson–Crick‐like T–HgII–T Base Pairs

The metallo DNA duplex containing mercury‐mediated T–T base pairs is an attractive biomacromolecular nanomaterial which can be applied to nanodevices such as ion sensors. Reported herein is the first crystal structure of a B‐form DNA duplex containing two consecutive T–Hg^II–T base pairs. The Hg^II ion occupies the center between two T residues. The N3‐Hg^II bond distance is 2.0 Å. The relatively short Hg^II‐Hg^II distance (3.3 Å) observed in consecutive T–Hg^II–T base pairs suggests that the metallophilic attraction could exist between them and may stabilize the B‐form double helix. To support this, the DNA duplex is largely distorted and adopts an unusual nonhelical conformation in the absence of Hg^II. The structure of the metallo DNA duplex itself and the Hg^II‐induced structural switching from the nonhelical form to the B‐form provide the basis for structure‐based design of metal‐conjugated nucleic acid nanomaterials.     

Intramolecular energy transfer in 3-amino-N-(7′-methoxy-4′-methylcoumaryl)phthalimide

The synthesis and fluorescence property of 3-amino-N-(7′-methoxy-4′-methylcoumaryl)phthalimide (AMMP) are described. The fluorescence of AMMP originated during the intramolecular energy transfer from the coumarin moiety to the phthalimde moiety in various solvents. The ab initio quantum chemical calculation of the AMMP revealed that the HOMO and LUMO of AMMP were localized in the coumarin and phthalimide moieties, respectively.