Toru Amaya

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Organization: Osaka University

Department: Department of Applied Chemistry, Graduate School of Engineering

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Polymer

Polyaniline Polyaniline

Organic Chemistry

Organocatalysis

Chemicals
References

Synthesis of phosphonic acid ring-substituted polyanilines via direct phosphonation to polymer main chains

Co-reporter:Toru Amaya;Izumi Kurata;Yuhi Inada;Tomohiro Hatai;Toshikazu Hirao

RSC Advances (2011-Present) 2017 vol. 7(Issue 62) pp:39306-39313

Publication Date(Web):2017/08/08

DOI:10.1039/C7RA04678B

Phosphonic acid ring-substituted polyanilines (PhosPANIs) were synthesized via reductive phosphonation of pernigraniline (a fully oxidized form of PANI) with P(OEt)3 and subsequent hydrolysis. The carbon–phosphorus bond formation was suggested from 31P NMR. This is the first example of direct phosphonation of PANI. The formal substitution ratio of the phosphonate to total number of phenyl rings in the polymer after the phosphonation reaction was up to 52%. The repetition of the phosphonation reaction procedure gave the diethyl PhosPANI (EtPhosPANI) with 73% substitution ratio. Hydrolysis of EtPhosPANIs afforded the desired PhosPANIs. The self-doping of the obtained PhosPANIs was clearly exhibited by ESR, XPS and UV-vis-NIR absorption spectroscopy. The drop-cast films of PhosPANIs showed electrical conductive properties with a level suitable for charge dissipation materials. The developed synthetic approach is considered to be valuable as a practical method for phosphonic acid self-doped conductive PANIs.

Quinonediimines as redox-active organocatalysts for oxidative coupling of aryl- and alkenylmagnesium compounds under molecular oxygen

Co-reporter:Toru Amaya, Riyo Suzuki and Toshikazu Hirao

Chemical Communications 2016 vol. 52(Issue 50) pp:7790-7793

Publication Date(Web):12 May 2016

DOI:10.1039/C6CC03053J

It is revealed that N,N′-diphenyl-p-benzoquinonediimine works as a redox-active organocatalyst for the oxidative homo-coupling of aryl- and alkenylmagnesium compounds under molecular oxygen. The catalytic cycle was formally monitored by 1H NMR experiments.

Self-doped polyaniline derived from poly(2-methoxyaniline-5-phosphonic acid) and didodecyldimethylammonium salt

Co-reporter:Toru Amaya, Ryosuke Sugihara, Dai Hata and Toshikazu Hirao

RSC Advances 2016 vol. 6(Issue 27) pp:22447-22452

Publication Date(Web):25 Feb 2016

DOI:10.1039/C5RA18468A

Salt formation of poly(2-methoxyaniline-5-phosphonic acid) (PMAP) with didodecyldimethylammonium bromide (DDDMABr) was performed to give the organic solvent soluble self-doped polyaniline, PMAP–DDDMA. The UV-vis-NIR absorption and ESR spectra clearly support the self-doping. This is in sharp contrast to the corresponding ammonium salt of poly(2-methoxyaniline-5-sulfonic acid), where dedoping was suggested. The drop-cast film of PMAP–DDDMA exhibited its conductivity.

Selective Intermolecular Oxidative Cross-Coupling of Enolates

Co-reporter:Toru Amaya; Yusuke Maegawa; Takaya Masuda; Yuma Osafune;Toshikazu Hirao

Journal of the American Chemical Society 2015 Volume 137(Issue 32) pp:10072-10075

Publication Date(Web):August 5, 2015

DOI:10.1021/jacs.5b05058

Selective intermolecular oxidative cross-coupling of enolates, which is a bond-forming reaction between carbanion equivalents, remains as an unsolved issue despite its potential utility for the direct synthesis of unsymmetrical 1,4-diones. The main difficulty derives from the unavoidable homo-coupling. Our strategy depends on the selective one-electron oxidation of one enolate to afford an electrophilic carbonyl α-radical species, followed by trapping with another enolate. The present study demonstrates the selective oxovanadium(V)-induced cross-coupling between boron and silyl enolates.

Polyaniline-Induced CH Arylation of Arenes with Arenediazonium Salts

Co-reporter:Dr. Toru Amaya;Dai Hata;Dr. Toshiyuki Moriuchi ;Dr. Toshikazu Hirao

Chemistry - A European Journal 2015 Volume 21( Issue 46) pp:16427-16433

Publication Date(Web):

DOI:10.1002/chem.201501969

Abstract

A reduced form of polyaniline has been shown to induce direct arylation of an arenediazonium salt with an arene (Gomberg–Bachmann reaction) to give the cross-coupling product in moderate to good yields under mild conditions. Various arenediazonium salts and arenes, including heteroarenes such as furans, thiophenes, and pyrroles, are employed for the reaction. The most favorable combination of substrates is an electron-poor arenediazonium salt with an electron-rich heteroarene. Investigation of the mechanism by reactions with radical scavengers and experiments on kinetic isotope effects indicated the occurrence of a radical chain reaction initiated by one-electron reduction of an arenediazonium salt by the polyaniline. Only 1 mol % (based on aniline tetramer) of the polyaniline is required for the cross-coupling reaction to occur. This reaction proceeds under metal-free conditions and with no need for photonic activation.

Regioselective functionalization of sumanene

Co-reporter:Toru Amaya, Takanori Ito, Shun Katoh, Toshikazu Hirao

Tetrahedron 2015 Volume 71(Issue 35) pp:5906-5909

Publication Date(Web):2 September 2015

DOI:10.1016/j.tet.2015.05.086

Doubly functionalized dioxosumanene was designed and synthesized to extend π conjugation bi-directionally. Friedel–Crafts double cycloalkylation to sumanene proceeded selectively to give the cycloalkylated compound. This compound was suggested to be the flattened structure as compared to sumanene, which induced the facile bowl-to-bowl inversion. Oxidation of the benzylic position was performed, and then a carbonyl group at the reverse side of the cycloalkylated arene was selectively protected with acetal to afford the doubly functionalized dioxosumanene.

Inside Back Cover: Polyaniline-Induced CH Arylation of Arenes with Arenediazonium Salts (Chem. Eur. J. 46/2015)

Co-reporter:Dr. Toru Amaya;Dai Hata;Dr. Toshiyuki Moriuchi ;Dr. Toshikazu Hirao

Chemistry - A European Journal 2015 Volume 21( Issue 46) pp:

Publication Date(Web):

DOI:10.1002/chem.201584603

Construction of a Hemifullerene Skeleton: A Regioselective Intramolecular Oxidative Cyclization

Co-reporter:Dr. Toru Amaya;Takanori Ito;Dr. Toshikazu Hirao

Angewandte Chemie International Edition 2015 Volume 54( Issue 18) pp:5483-5487

Publication Date(Web):

DOI:10.1002/anie.201500548

Abstract

A two-step synthesis of a strained π bowl, with hemifullerene skeleton from sumanene, was achieved in a high yield. The first step is a base-promoted condensation reaction with a benzophenone compound, bis(3,5-dimethylphenyl)methanone. The second step is the regioselective intramolecular oxidative cyclization, which is a key reaction for the hemifullerene skeleton synthesis. This regioselective cyclization is likely to be under thermodynamic control. This strategy will allow facile synthesis of various highly strained π bowls.

Construction of a Hemifullerene Skeleton: A Regioselective Intramolecular Oxidative Cyclization

Co-reporter:Dr. Toru Amaya;Takanori Ito;Dr. Toshikazu Hirao

Angewandte Chemie 2015 Volume 127( Issue 18) pp:5573-5577

Publication Date(Web):

DOI:10.1002/ange.201500548

Abstract

Synthesis of self-doped conducting polyaniline bearing phosphonic acid

Co-reporter:Toru Amaya, Yasushi Abe, Yuhi Inada, Toshikazu Hirao

Tetrahedron Letters 2014 Volume 55(Issue 29) pp:3976-3978

Publication Date(Web):16 July 2014

DOI:10.1016/j.tetlet.2014.04.115

As a self-doped conducting polyaniline bearing phosphonic acid, poly(2-methoxyaniline-5-phosphonic acid) (PMAP) was synthesized via oxidative polymerization of 2-methoxyaniline-5-phosphonic acid. The pyridinium salt of thus-obtained PMAP was water-soluble and its film exhibited conductivity.

Conductivity of poly(2-methoxyaniline-5-phosphonic acid)/amine complex and its charge dissipation property in electron beam lithography

Co-reporter:Toru Amaya, Yasushi Abe, Hiroki Yamamoto, Takahiro Kozawa, Toshikazu Hirao

Synthetic Metals 2014 Volume 198() pp:88-92

Publication Date(Web):December 2014

DOI:10.1016/j.synthmet.2014.09.027

•Conductivity for amine complexes of poly(2-methoxyaniline-5-phosphonic acid) (PMAP) (up to 10 S m−1).•Higher conductivity of PMAP compared to poly(2-methoxyaniline-5-phosphonic acid monoethyl ester) (PMAPE).•Efficient charge dissipation property of PMAP/pyridine (1:2) and PMAP/{CF3CH2NH2/NH3 (4:1)} (1:3) complexes in the electron beam lithography.The present study summarizes the conductivity of the drop-cast film for various amine complexes of the novel self-doped polyanilines bearing phosphonic acid, poly(2-methoxyaniline-5-phosphonic acid) (PMAP) and poly(2-methoxyaniline-5-phosphonic acid monoethyl ester) (PMAPE). The conductivity was revealed to depend on the kind and amount of the amine base. The tendency of PMAP and PMAPE complexes was similar, but the PMAP ones exhibited the higher conductivity than the PMAPE ones. In the case of the pyridine and CF3CH2NH2 complexes of PMAP, the conductivity more than 10 S m−1 was kept even in the presence of four equivalents of the amine based on the phosphonic acid moiety. The charge dissipation property of the PMAP/pyridine (1:2) complex was also investigated qualitatively by top-coating a resist on a quartz substrate in the electron beam lithography. The obtained pattern clearly showed the charge dissipation property. Use of PMAP/{CF3CH2NH2/NH3 (4:1)} (1:3) complex made it possible with the development using only water in place of an aqueous NMe4OH solution.

Characterization of self-doped conducting polyanilines bearing phosphonic acid and phosphonic acid monoester

Co-reporter:Yasushi Abe, Toru Amaya, Yuhi Inada, Toshikazu Hirao

Synthetic Metals 2014 Volume 197() pp:240-245

Publication Date(Web):November 2014

DOI:10.1016/j.synthmet.2014.09.020

•Characterization of poly(2-methoxyaniline-5-phosphonic acid) (PMAP) and poly(2-methoxyaniline-5-phosphonic acid monoethyl ester) (PMAPE).•Efficient self-doping for PMAP.•Spin-coating thin film (up to 90% transparency).•Delocalization of polaron.•Chemical oxidation and reduction of PMAP and PMAPE.Novel self-doped polyanilines bearing phosphonic acid, poly(2-methoxyaniline-5-phosphonic acid) (PMAP) and poly(2-methoxyaniline-5-phosphonic acid monoethyl ester) (PMAPE) were characterized in the following properties: (1) thermostability, (2) morphology in the solid state, (3) absorption and transparency in the spin-coating film, (4) delocalization of polaron, (5) doping efficiency, and (6) chemical oxidation and reduction. The UV–vis–NIR absorption spectra of the spin-coating films of PMAP/pyridine (1:2) and PMAPE/pyridine (1:1) show the polaron band and free carrier tail, which are characteristic to the conducting polymers. The highly transparent films of them (up to ∼90% transparency) were formed by spin-coating. Concerning the property of the polaron in the polymer, the ESR spectra suggest that polaron of PMAP/pyridine (1:2) is more delocalized than that of PMAPE/pyridine (1:1). The XPS experiments indicate that the doping efficiency of PMAP is much higher than that of PMAPE, which is likely to be due to diprotic acid units derived from phosphonic acid of PMAP. Oxidation and reduction of PMAP and PMAPE were demonstrated by treatment with the corresponding oxidant {(NH4)2S2O8} and reductant (N2H4·H2O), respectively.

Synthesis of self-doped conducting polyaniline bearing phosphonic acid monoester

Co-reporter:Toru Amaya, Yasushi Abe, Yuhi Inada, Toshikazu Hirao

Synthetic Metals 2014 Volume 195() pp:137-140

Publication Date(Web):September 2014

DOI:10.1016/j.synthmet.2014.05.021

•Synthesis of poly(2-methoxyaniline-5-phosphonic acid monoethyl ester) (PMAPE).•First example of the conducting self-doped polymers with phosphonic acid monoester.•High water-solubility of the pyridinium salt of the thus-obtained PMAPE.•Conductivity (1.3 S/m).•High transparency of the spin-coating film.Poly(2-methoxyaniline-5-phosphonic acid monoethyl ester) (PMAPE) was synthesized via oxidative polymerization of 2-methoxyaniline-5-phosphonic acid monoethyl ester. This is the first example of the conducting self-doped polymers with phosphonic acid monoester. Self-doping of the polymer was shown by UV–vis–NIR and ESR measurements. The pyridinium salt of the thus-obtained PMAPE was water-soluble and its film exhibited conductivity.Poly(2-methoxyaniline-5-phosphonic acid monoethyl ester) (PMAPE) was synthesized via oxidative polymerization of 2-methoxyaniline-5-phosphonic acid monoethyl ester. Self-doping of the polymer was shown by UV–vis–NIR and ESR measurements. The pyridinium salt of the thus-obtained PMAPE was water-soluble and its film exhibited conductivity (1.3 S/m).

Deprotonation-Induced Efficient Delocalization of Polaron in Self-Doped Poly(anilinephosphonic acid)

Co-reporter:Toru Amaya, Yasushi Abe, and Toshikazu Hirao

Macromolecules 2014 Volume 47(Issue 22) pp:8115-8118

Publication Date(Web):November 10, 2014

DOI:10.1021/ma5016209

Quinonediimine-Induced Oxidative Coupling of Organomagnesium Reagents

Co-reporter:Dr. Toru Amaya;Riyo Suzuki ;Dr. Toshikazu Hirao

Chemistry - A European Journal 2014 Volume 20( Issue 3) pp:653-656

Publication Date(Web):

DOI:10.1002/chem.201301993

Abstract

N,N′-Diphenyl-p-benzoquinonediimine, a redox-active unit of polyaniline, efficiently induced the oxidative homocoupling of various aryl- and vinylmagnesium reagents in suppressing the side reactions, such as 1,2- or 1,4-addition reaction.

Quinonediimines as redox-active organocatalysts for oxidative coupling of aryl- and alkenylmagnesium compounds under molecular oxygen

Co-reporter:Toru Amaya, Riyo Suzuki and Toshikazu Hirao

Chemical Communications 2016 - vol. 52(Issue 50) pp:NaN7793-7793

Publication Date(Web):2016/05/12

DOI:10.1039/C6CC03053J

Synthesis of oxindoles via reductive CO2 fixation

Co-reporter:Toru Amaya, Izumi Kurata and Toshikazu Hirao

Inorganic Chemistry Frontiers 2016 - vol. 3(Issue 8) pp:NaN933-933

Publication Date(Web):2016/06/29

DOI:10.1039/C6QO00107F

The synthesis of 3-aryl-3-hydroxy-2-oxindoles, which are a structural motif found in various natural products and pharmaceutically active compounds, was conducted via reductive coupling of (2-aminophenyl)(aryl)methanone derivatives and CO2 as a key step. The conditions employing Mg with chlorotrimethylsilane in DMA are the best for the reductive coupling, where the aryl halide moiety is intact. This reaction proceeds well without the protection of the amino group. The reductive coupling and acid-catalyzed lactam formation can be performed in a one-pot reaction to give the oxindoles.