Supramolecular organogel formation behaviors of beads-on-string shaped poly(azomethine)s dependent on POSS structures in the main chains

Organogel formation was observed for isobutyl-substituted cage octasilsesquioxane (T₈) in the main-chain type polyazomethines, while precipitates instead of gel formation were observed for phenyl-substituted double-decker-shaped silsesquioxanes (DDSQ)-poly(azomethine)s.

2-Arylbenzo[b]arsoles: an experimental and computational study on the relationship between structural and photophysical properties

Benzo[b]arsole derivatives, being arsenic analogues of indole, were synthesized by utilizing a safely prepared arsenic precursor. The structural and photophysical properties of the obtained 2-arylbenzo[b]arsoles were experimentally and computationally studied in comparison with those of 1,2,5-triarylarsoles and 9-phenylarsafluorene. It was found that the emission color and/or quantum yield were significantly affected by substituents on the luminescent center and metal-coordination to the arsenic atom. This is the first study on the structure-property relationship of benzo[b]arsole derivatives.

Systematic Study on the Catalytic Arsa-Wittig Reaction

Efficient catalytic arsa-Wittig reactions have been developed by using 1-phenylarsolane as a catalyst. A wide array of aldehydes was converted to the corresponding olefins in high yields with moderate to excellent E stereoselectivity in the presence of a catalytic amount of 1-phenylarsolane. Moreover, density functional theory calculations were carried out to afford insight into the E/Z selectivity.

Surface Segregation of a Star-Shaped Polyhedral Oligomeric Silsesquioxane in a Polymer Matrix

A simple way to control only the surface properties of polymer materials, without changing the bulk properties, has long been desired. The segregation behavior when a component with a tiny amount fed into the matrix is thermodynamically enriched at the surface is one of the candidate methods. This capability was examined herein by focusing on a star-shaped polyhedral oligomeric silsesquioxane (s-POSS), where the central POSS unit is tethered to eight isobutyl-substituted POSS cages as a surface modifier. X-ray photoelectron spectroscopy revealed that the surface of a film of poly(methyl methacrylate) (PMMA) was almost completely covered with POSS units by adding just 5 wt % s-POSS to it. The segregated POSS dramatically altered the physical properties such as molecular motion and the mechanical and dielectric responses at the surface of the PMMA film. These findings make it clear that s-POSS is an excellent surface modifier for glassy polymers.

Fundamental Study on Arsenic(III) Halides (AsX3; X = Br, I) toward the Construction of C3-Symmetrical Monodentate Arsenic Ligands

Arsenic ligands have attracted considerable attention in coordination chemistry. Arsenic(III) halides are the most important starting materials in the preparation of monodentate arsenic ligands. In this work, we optimized the synthetic methodologies of arsenic(III) halides (AsX₃; X = Br, I) and examined the difference of their physical properties such as solubility to organic solvent and reactivity to nucleophiles. In addition, a wide variety of monodentate arsenic ligands were prepared with the obtained AsX₃. Finally, the obtained monodentate arsenic ligands were utilized for copper-free Sonogashira cross-coupling reaction in the reaction system with porphyrin. The results showed that monodentate arsenic ligands have higher catalytic activity compared with triphenylphosphine because of the difference of the electronic features of lone pairs between arsenic and phosphorus atoms.

Dipyridinoarsole: a new class of stable and modifiable heteroatom-bridged bipyridines

Herein, we report our experimental and computational investigations on a stable and modifiable As-bridged dipyridinoheterole, dipyridinoarsole. Oxidation of the arsenic atom changes the frontier orbital energies and quaternization of nitrogen atoms produces electrochromic materials. Dipyridinoarsole is suitable for practical applications due to its superior stability compared to its phosphole analogues.