Porphyrin Network Polymers Prepared via a Click Reaction and Facilitated Oxygen Permeation Through Their Membranes

Network polymers of cobaltporphyrin derivatives are prepared by a facile click reaction via the Michael addition of acetoacetate‐substituted tetraphenyl cobaltporphyrin and tri‐ or tetra‐acrylates. The conversion is saturated for 1 h in the presence of a catalyst, which almost reaches the same gelation point of the formed network polymers. Deeply and homogeneously red‐colored membranes with a sub‐micrometer thickness are yielded on a porous supporting membrane. They are still tough even with a very high content of the rigid porphyrin residue. The oxygen permeability is high, at 10–100 Barrer, and the oxygen/nitrogen permselectivity (P_O2/P_N2) is significantly enhanced with the porphyrin content reaching 30, for the membranes with ca. 70 wt% porphyrin content.

     

New Synthesis of Poly(Phenylenesulfide)S Through an Electron Transfer

Poly(p-phenylenesulfide) (PPS) is efficiently and conveniently produced by a cationic and oxidative polymerization. Diphenyldisulfide is polymerized to PPS through one electron transfer at room temperature. The polymer is isolated as a white powder whose 1,4-structure is confirmed by IR. Phenylbis(phenylthio)sulfonium ion acts as an active species which is formed by oxidation of the S-S bond of diphenyldisulfide, and electrophilically substitutes on the phenyl ring. This polymerization is applicable to the polymerization of alkyl-substituted diphenyldisulfides to give PPSs, such as poly(2-methylphenylenesulfide) and poly(3,5-dimethylphenylene-sulfide).     

Magnetic Properties of Conjugated Phenoxy Polyradicals

Formation and magnetic properties of π-conjugated phenoxy radicals bearing a porphyrin macrocycle or a polyacetylenic backbone are described. Tetrakis(3,5-di-t-butyl-4-hydroxyphenyl)porphinato-metals (7-M) [M = Zn(II), VO(II), and Cu(II)] were oxidized to give the corresponding stable monoradical and biradical. Magnetic properties of the radical species depend on the magnetic orbital of the central metal ion. ESR hfs structure reveals that the biradical for 7-Zn and—VO are in the triplet (S = 1) and quartet state (S = 3/2), respectively. Poly(3,5-di-t-butyl-4-hydroxyphenylacetylene) (8) and poly(p-ethynylphenylhydrogalvinoxyl) (9) with molecular weights of ～ /10⁴ are characterized. ESR spectra with hyperfine structure for 8 indicate that the phenoxy radicals are conjugated with the polyacetylenic main chain over ～7 monomer units as a “neutral soliton.” Formed polyradicals for 8 and 9 are surprisingly stable, even in the solid state, due to resonance stabilization and/or steric effect of the conjugated main chain. An antiferromagnetic interaction is observed for oxidized 8 with a spin concentration above 10 mol%.     

Complexation of Terbium Ion with the Copolymer of Acrylic Acid and Acrylamide Grafted onto Polyethylene

Acrylic acid (AA) and acrylamide (AAm) were graft copolymerized onto polyethylene powder by the preirradiation method. The PE powder grafted with both AA and AAm (PE-g-(AA-co-AAm)) rapidly adsorbed Tb ion with an efficiency higher than did PE powder grafted with AA (PE-g-AA). The complex formation constant of Tb ion with PE-g-(AA-co-AAm) was larger than that with PE-g-AA because the introduction of the acrylamide part decreased the steric hindrance for complexation between Tb and the carboxyl group of the graft chains. Tb ion was efficiently separated from transition metal ions, such as Co, upon passage of a solution through a column packed with PE-g-(AA-co-AAm).     

Synthesis of Polyphenylene Thioethers Through Cationic Oxidative Polymerization

Polyaromatic sulfides are efficiently and conveniently prepared by cationic oxidative polymerization. Diphenyl disulfides are quantitatively polymerized to yield poly(p-phenylene sulfide)s as white powders whose structure predominately contains 1,4-phenylene sul-fide bonds. The disulfides are oxidized to phenylbis(phenylthio) sulfonium cations as active species of the polymerization. Repeating the oxidation and electrophilic reaction of the cation to the p-position of disulfides yields the polymer.     

Facile regio- and stereoselective hydrometalation of alkynes with a combination of carboxylic acids and group 10 transition metal complexes: selective hydrogenation of alkynes with formic acid

A facile, highly stereo- and regioselective hydrometalation of alkynes generating alkenylmetal complex is disclosed for the first time from a reaction of alkyne, carboxylic acid, and a zerovalent group 10 transition metal complex M(PEt(3))(4) (M = Ni, Pd, Pt). A mechanistic study showed that the hydrometalation does not proceed via the reaction of alkyne with a hydridometal generated by the protonation of a carboxylic acid with Pt(PEt(3))(4), but proceeds via a reaction of an alkyne coordinate metal complex with the acid. This finding clarifies the long proposed reaction mechanism that operates via the generation of an alkenylpalladium intermediate and subsequent transformation of this complex in a variety of reactions catalyzed by a combination of Br?nsted acid and Pd(0) complex. This finding also leads to the disclosure of an unprecedented reduction of alkynes with formic acid that can selectively produce cis-, trans-alkenes and alkanes by slightly tuning the conditions.     

Aqueous electrochemistry of poly(vinylanthraquinone) for anode-active materials in high-density and rechargeable polymer/air batteries

A layer of poly(2-vinylanthraquinone) on current collectors underwent reversible electrode reaction at -0.82 V vs Ag/AgCl in an aqueous electrolyte. A repeatable charging/discharging cycles with a redox capacity comparable to the formula weight-based theoretical density at the negative potential suggested that all of the anthraquinone pendants in the layer was redox-active, that electroneutralization by an electrolyte cation was accomplished throughout the polymer layer, and that the layer stayed on the current collector without exfoliation or dissolution into the electrolyte during the electrolysis. The charging/discharging behavior of the polymer layer in the aqueous electrolyte revealed the capability of undergoing electrochemistry even in the nonsolvent of the pendant group, which offered insight into the nature of the anthraquinone pendants populated on the aliphatic chain. Charging/discharging capability of air batteries was accomplished by using the polymer layer as an organic anode-active material. A test cell fabricated using the conventional MnO(2)/C cathode catalyst exhibited a discharging voltage at 0.63 V corresponding to their potential gap and a charging/discharging cycle of more than 500 cycles without loss of the capacity.     

On perfect one-factorization of the complete graphK 2p

Anderson [1, 2] and Nakamura [4] have constructed perfect 1-factorizations ofK _2p independently, wherep is an odd prime. In this paper, we show that these two 1-factorizations are isomorphic.