Naoto Matsuyama

Nickel-Catalyzed Direct Alkynylation of Azoles with Alkynyl Bromides

The direct C-H alkynylation of azoles with alkynyl bromides proceeds efficiently in the presence of a nickel-based catalyst system. The reaction enables the introduction of various alkynyl groups bearing aryl, alkenyl, alkyl, and silyl substituents to the azole cores. In some cases, addition of a catalytic amount of CuI is observed to accelerate the direct coupling dramatically.

Nickel- and Copper-Catalyzed Direct Alkynylation of Azoles and Polyfluoroarenes with Terminal Alkynes under O2 or Atmospheric Conditions

The direct C-H alkynylation of azoles with terminal alkynes proceeds efficiently under a nickel/O(2) catalytic system. On the other hand, a copper/air catalyst enables the coupling of polyfluoroarenes with terminal alkynes. These catalyses provide new accesses to arylacetylenes through the formal direct Sonogashira coupling.

Room temperature direct alkynylation of 1,3,4-oxadiazoles with alkynyl bromides under copper catalysis.

The direct alkynylation reaction of 1,3,4-oxadiazoles with alkynyl bromides efficiently proceeds in the presence of a copper catalyst at room temperature to create the corresponding heteroaryl-alkynyl linkage in good yields. This direct coupling provides a rapid and convergent access to oxadiazole core pi-conjugated systems.

Total oxidation of toluene on Pt/CeO2–ZrO2–Bi2O3/γ-Al2O3 catalysts prepared in the presence of polyvinyl pyrrolidone

Pt/CeO(2)-ZrO(2)-Bi(2)O(3)/gamma-Al(2)O(3) (Pt/CZB/Al(2)O(3)) catalysts for the catalytic combustion of toluene, which is one of the volatile organic compounds (VOCs), were prepared by the wet impregnation method in the presence of polyvinyl pyrrolidone (PVP). X-ray powder diffraction, transmission electron microscopy, and BET specific surface area measurement using N(2) adsorption have been used to characterize the catalysts. The catalytic test was conducted from room temperature in a flow of 900 ppm of toluene in air and gas hourly space velocity (GHSV) of 8000 h(-1). The catalytic activity was evaluated in terms of C(7)H(8) conversion and the gas composition after the reaction was analyzed using two gas chromatographs with a flame ionization detector (FID) and a thermal conductivity detector (TCD). The Pt/CZB/Al(2)O(3) catalysts are specific for the total toluene oxidation and CO and any toluene-derivative compounds were not detected as by-products. The specific surface area of the catalysts was increased by the addition of PVP in the preparation process. By the optimization of the amount of platinum, complete oxidation of toluene was realized at a temperature as low as 120 degrees C on a 7 wt%Pt/16 wt%Ce(0.64)Zr(0.15)Bi(0.21)O(1.895)/gamma-Al(2)O(3) catalyst.

Synthesis and physical properties of a ball-like three-dimensional π-conjugated molecule

Curved π-conjugated molecules with closed and three-dimensional (3D) structures, such as fullerenes and carbon nanotubes, have been the subject of intensive research due to their potential applications in molecular electronics. However, basic molecular skeletons of 3D molecules are limited because of the lack of a rational and selective synthetic method by organic synthesis. Here we report the synthesis of a 3D π-conjugated molecule based on the platinum-mediated assembly of four molecules of a stannylated trisubstituted benzene derivative forming a hexanuclear platinum complex with an octahedral shape, from which reductive elimination of platinum gave the target molecule. As many supramolecular transition metal-ligand complexes with 3D cages and polyhedral structures have been synthesized by self-assembly of ligands and metals, the current assembly/reductive elimination strategy could provide a variety of new 3D π-conjugated molecules with different structures and topologies, which are challenging to obtain using conventional synthetic methods.

Nickel- and rhodium-catalyzed addition of terminal silylacetylenes to propargyl amines: catalyst-dependent complementary regioselectivity.

The cross-addition of terminal silylacetylenes to gamma-arylated propargyl amines occurs efficiently via C-H cleavage by using either a nickel or rhodium catalyst. Taking advantage of the catalyst-controlled switching of regioselectivity in the reaction, both the 2- and 3-alkynylallylamines are readily accessible from the same starting materials.

Pressure Modulation of Backbone Conformation and Intermolecular Distance of Conjugated Polymers Toward Understanding the Dynamism of π-Figuration of their Conjugated System.

Continuous tuning of the backbone conformation and interchain distance of a π-conjugated polymer is an essential prerequisite to unveil the inherent electrical and optical features of organic electronics. To this end, applying pressure in a hydrostatic medium or diamond anvil cell is a facile approach without the need for side-chain synthetic engineering. We report the development of high-pressure, time-resolved microwave conductivity (HP-TRMC) and evaluation of transient photoconductivity in the regioregular poly(3-hexylthiophene) (P3HT) film and its bulk heterojunction blend with methanofullerene (PCBM). X-ray diffraction experiments under high pressure were performed to detail the pressure dependence of π-stacking and interlamellar distances in P3HT crystallites and PCBM aggregates. The HP-TRMC results were further correlated with high-pressure Raman spectroscopy and density functional theory calculation. The increased HP-TRMC conductivity of P3HT under pressure was found to be relevant to the planarity of the backbone conformation and intramolecular hole mobility. The effects of pressure on the backbone planarity are estimated to be ∼0.3 kJ mol(-1) based on the compressibility derived from the X-ray diffraction under high pressure, suggesting the high enough energy to cause modulation of the planarity in terms of the Landau-de Gennes free energy of isolated P3HT chains as 0.23 kJ mol(-1). In contrast, the P3HT:PCBM blend showed a simple decrease in photoconductivity irrespective of the identical compressive behavior of P3HT. A mechanistic insight into the interplay of intra- and intermolecular mobilities is a key to tailoring the dynamic π-figuration associated with electrical properties, which may lead to the use of HP-TRMC for exploring divergent π-conjugated materials at the desired molecular arrangement and conformation.

Disilanyl Double-Pillared Bisternaphthyl (SiDPBT): Synthesis and Interfused Packing Structures with Herringbone and π-Stack Motifs

A silacyclophane molecule with two disilanyl pillars and two oligoarylene units was synthesized. The molecule was packed in a single crystal with a new motif interfusing π-stack and herringbone packing structures. The hole transporting ability of the solid was revealed by using the flash-photolysis time-resolved microwave conductivity method. The molecular structure, albeit a singly-bonded arylene macrocycle, was rigidified by the unique packing array, which favorably contributed to the hole transporting ability of the solid via the small reorganization energy through the charge transport.