Formation of perfluorinated polyphenylenes by multiple pentafluorophenylation using C6F5Si(CH3)3

Pentafluorophenylation of perfluoroarenes with C₆F₅Si(CH₃)₃ was investigated by using NMR and MALDI-TOF-MS techniques. Successive multiple pentafluorophenylation easily occurred not only on the para-position but also on the ortho-positions to provide perfluorinated p-phenylene and m-phenylene compounds. The perfluoroarenes having electron-withdrawing substituents provided oligo- to poly-(phenylene)s depending on the added amounts of C₆F₅Si(CH₃)₃, while the perfluoroarenes having electron-donor substituents gave H(C₆F₄)_nF polymers produced from C₆F₅H, which was the decomposed product of C₆F₅Si(CH₃)₃.     

3,3,3-Trifluoro-2,2-dihydroxypropanesulfonamides as building blocks for trifluoromethyl-containing pyrazoles and benzimidazoles

1-Alkyl-3-trifluoromethylpyrazole-4-sulfonamides 10 , (2-trifluoromethyl-2,3-dihydrobenzimidazol-2-yl)methanesulfonamides 12 , and (2-benzimidazolyl)metbanesulfonamides 13 were prepared starting from 3,3,3-trifluoro-2,2-dihydroxypropanesulfonamides 1 .     

Synthesis of dithia- and tetrathiacyclophanes incorporating isoxazole units

The reaction of 5-bromomethyl-3-(p-bromomethylphenyl)isoxazole with o-, m-, and p-bis(mercap-tomethyl)benzenes gave the corresponding dithia- and/or tetrathiaisoxazolophanes, whose relative yields strongly depended upon the nature of the mercaptomethyl compound. The above isoxazole dibromide reacted with the bis(mercaptomethyl)isoxazole to afford a mixture of two isomeric dithiaisoxazolophanes.     

Preparation of immobilized tannins for protein adsorption

Preparation and adsorption specificity of tannins immobilized by covalent binding on water-insoluble matrices were investigated. Immobilized tannins were prepared by condensing cyanogen bromide activated tannins with aminohexyl derivatives of several kinds of matrices. The most suitable matrix for the immobilization of tannin was alkali-treated cellulose powder. The concentration of sodium hydroxide solution for alkali treatment influenced the adsorption capacity of immobilized tannin for a protein, but temperature and time for alkali treatment did not. Immobilized tannins having spacers of long chain length exhibited high adsorption capacity for a protein. Chinese gallotannin was the most favorable ligand for protein adsorption. The immobilization of tannin on aminohexyl matrices was also possible by using epichlorohydrin instead of cyanogen bromide. The maximum adsorption capacity of the immobilized tannin for a protein was about 50 mg/ml of the absorbent. Immobilized tannin adsorbed proteins specifically but did not absorb low molecular weight compounds.     

Space-time aspects of superconductivity

A set of electromagnetic responses of superconductivity, [A] the zero-resistivity and [B] the perfect diamagnetism, has been reconsidered both electrodynamically and quantum mechanically. We point out an equivalence between the London gauge with the boundary condition or his “rigidity” of wave function and the phase locking in the BCS-type macroscopic wave function Φ_macro or the Ginzburg- Landau order parameter at T= 0 K. By reexamining the macroscopic wave function of condensed pairs Φ_macro at the ground state with the Josephson concept of coherent phase locking and the energy spectrum of quasi-particle excitation, we realize that the electric response [A] and magnetic response [B] can be decoupled and separable as independent with each other in the limits of an electrostatic field and of a uniform magnetic field rather than in an electrodynami-cal consideration. They are equally substantial in the physics of superconductivity. We recognize first a proper view to simultaneously account for [A] the zero-resistivity and [B] the perfect diamagnetism in the space-time aspects. By supplementing these space-time aspects with a concept of the gauge field theory, we can reach a further consistent and finally complete understanding of the theory of superconductivity.     

Hitting Matrix and Domino Tiling with Diagonal Impurities

As a continuation to our previous work (Nakano and Sadahiro in Fundam. Inform. 117:249–264, 2012; Nakano and Sadahiro in J. Stat. Phys. 139(4):565–597, 2010), we consider the domino tiling problem with impurities. (1) If we have more than two impurities on the boundary, we can compute the number of corresponding perfect matchings by using the hitting matrix method (Fomin in Trans. Am. Math. Soc. 353(9):3563–3583, 2001). (2) We have an alternative proof of the main result in Nakano and Sadahiro (Fundam. Inform. 117:249–264, 2012) and result in (1) above using the formula by Kenyon and Wilson (Trans. Am. Math. Soc. 363(3):1325–1364, 2011; Electron. J. Comb. 16(1):112, 2009) of counting the number of groves on circular planar graphs. (3) We study the behavior of the probability of finding the impurity at a given site when the size of the graph tends to infinity, as well as the scaling limit of those.     

Relations between the Jones andQ polynomials for 2-bridge and 3-braid links

Dedicated to Professor Hirosi Toda on his 60th birthday     

Isolation of keto-s-phenylthioxime of [23]cyclophane-1,2-dione. Re-visited contraction of 1,2,5-thiadiazole ring incorporated in a [23]cyclophane bridge by phenylmagnesium bromide

[2³]Paracyclophane derivative 3 of keto-S-phenylthioxime which is the hydrolyzed product of the hypothetical intermediate in the reaction of 1,2,5-thiadiazole with organometallic reagents, was obtained, together with diketone 1 , in the reaction of 1,2,5-thiadiazolo[2³]paracyclophane 2 with two equivalents of phenylmagnesium bromide. Contrary, [2³]metacyclophane 7 gave only diketone 12 in the reaction with phenylmagnesium bromide under the same conditions.     

Carbon Nanosheets by Morphology‐Retained Carbonization of Two‐Dimensional Assembled Anisotropic Carbon Nanorings

Two‐dimensional (2D) carbon nanomaterials possessing promising physical and chemical properties find applications in high‐performance energy storage devices and catalysts. However, large‐scale fabrication of 2D carbon nanostructures is based on a few specific carbon templates or precursors and poses a formidable challenge. Now a new bottom‐up method for carbon nanosheet fabrication using a newly designed anisotropic carbon nanoring molecule, CPPhen, is presented. CPPhen was self‐assembled at a dynamic air–water interface with a vortex motion to afford molecular nanosheets, which were then carbonized under inert gas flow. Their nanosheet morphologies were retained after carbonization, which has never been seen for low‐molecular weight compounds. Furthermore, adding pyridine as a nitrogen dopant in the self‐assembly step successfully afforded nitrogen‐doped carbon nanosheets containing mainly pyridinic nitrogen species.