Fast trigonal/tetragonal interconversion followed by slow chelate-ring closure in the complexation of boronic acids

Yoshiaki Yamamoto, Takeshi Matsumura, Norihiro Takao, Hiroaki Yamagishi, Masato Takahashi, Satoshi Iwatsuki, Koji Ishihara

    研究成果: Article

    28 引用 (Scopus)

    抄録

    Which of the step is rate determining in the complexation of boronic acid with bidentate ligands, the first trigonal/tetragonal interconversion step or the following chelate-ring closure step ? No one could have ever answered this simple question clearly. In this study, we for the first time gave an explicit answer to this question. Reaction systems were devised for kinetic measurements to answer this simple question. At first, pKa values of 15 boronic acids were determined spectrophotometrically at I = 1.0 M and 25 °C: pK a = 6.40 ± 0.06 for 3,5-Cl2PhB(OH)2, 6.62 ± 0.03 for 3,5-(CF3)2PhB(OH)2, 6.95 ± 0.09 for 3,5-Br2PhB(OH)2, 7.04 ± 0.03 for 3-NO2PhB(OH)2, 7.08 ± 0.03 for 3,5-F 2PhB(OH)2, 7.12 ± 0.02 for 2,4-F 2PhB(OH)2, 7.39 ± 0.02 for 4-CF3PhB(OH) 2, 7.50 ± 0.02 for 3-FPhB(OH)2, 7.83 ± 0.02 for 2-FPhB(OH)2, 7.87 ± 0.01 for 3-CF3PhB(OH) 2, 8.11 ± 0.01 for 2-ClPhB(OH)2, 8.14 ± 0.03 for 3-(COOH)PhB(OH)2, 8.15 ± 0.03 for 3-(CH 3CO)Ph(OH)2, 8.20 ± 0.01 for 3-ClPhB(OH) 2, and 8.66 ± 0.05 for 4-FPhB(OH)2. The kinetic results for the reactions of some of these boronic acids with 4-isopropyltropolone clearly show that the rate-determining step is not the interconversion step but the chelate-ring closure step.

    元の言語English
    ページ(範囲)3355-3361
    ページ数7
    ジャーナルInorganica Chimica Acta
    358
    発行部数12
    DOI
    出版物ステータスPublished - 2005 8 1

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    Boronic Acids
    Complexation
    chelates
    closures
    acids
    Acids
    rings
    Kinetics
    Ligands
    kinetics
    methylidyne
    ligands

    ASJC Scopus subject areas

    • Biochemistry
    • Inorganic Chemistry
    • Physical and Theoretical Chemistry
    • Materials Chemistry

    これを引用

    Fast trigonal/tetragonal interconversion followed by slow chelate-ring closure in the complexation of boronic acids. / Yamamoto, Yoshiaki; Matsumura, Takeshi; Takao, Norihiro; Yamagishi, Hiroaki; Takahashi, Masato; Iwatsuki, Satoshi; Ishihara, Koji.

    :: Inorganica Chimica Acta, 巻 358, 番号 12, 01.08.2005, p. 3355-3361.

    研究成果: Article

    Yamamoto, Yoshiaki ; Matsumura, Takeshi ; Takao, Norihiro ; Yamagishi, Hiroaki ; Takahashi, Masato ; Iwatsuki, Satoshi ; Ishihara, Koji. / Fast trigonal/tetragonal interconversion followed by slow chelate-ring closure in the complexation of boronic acids. :: Inorganica Chimica Acta. 2005 ; 巻 358, 番号 12. pp. 3355-3361.
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    abstract = "Which of the step is rate determining in the complexation of boronic acid with bidentate ligands, the first trigonal/tetragonal interconversion step or the following chelate-ring closure step ? No one could have ever answered this simple question clearly. In this study, we for the first time gave an explicit answer to this question. Reaction systems were devised for kinetic measurements to answer this simple question. At first, pKa values of 15 boronic acids were determined spectrophotometrically at I = 1.0 M and 25 °C: pK a = 6.40 ± 0.06 for 3,5-Cl2PhB(OH)2, 6.62 ± 0.03 for 3,5-(CF3)2PhB(OH)2, 6.95 ± 0.09 for 3,5-Br2PhB(OH)2, 7.04 ± 0.03 for 3-NO2PhB(OH)2, 7.08 ± 0.03 for 3,5-F 2PhB(OH)2, 7.12 ± 0.02 for 2,4-F 2PhB(OH)2, 7.39 ± 0.02 for 4-CF3PhB(OH) 2, 7.50 ± 0.02 for 3-FPhB(OH)2, 7.83 ± 0.02 for 2-FPhB(OH)2, 7.87 ± 0.01 for 3-CF3PhB(OH) 2, 8.11 ± 0.01 for 2-ClPhB(OH)2, 8.14 ± 0.03 for 3-(COOH)PhB(OH)2, 8.15 ± 0.03 for 3-(CH 3CO)Ph(OH)2, 8.20 ± 0.01 for 3-ClPhB(OH) 2, and 8.66 ± 0.05 for 4-FPhB(OH)2. The kinetic results for the reactions of some of these boronic acids with 4-isopropyltropolone clearly show that the rate-determining step is not the interconversion step but the chelate-ring closure step.",
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    T1 - Fast trigonal/tetragonal interconversion followed by slow chelate-ring closure in the complexation of boronic acids

    AU - Yamamoto, Yoshiaki

    AU - Matsumura, Takeshi

    AU - Takao, Norihiro

    AU - Yamagishi, Hiroaki

    AU - Takahashi, Masato

    AU - Iwatsuki, Satoshi

    AU - Ishihara, Koji

    PY - 2005/8/1

    Y1 - 2005/8/1

    N2 - Which of the step is rate determining in the complexation of boronic acid with bidentate ligands, the first trigonal/tetragonal interconversion step or the following chelate-ring closure step ? No one could have ever answered this simple question clearly. In this study, we for the first time gave an explicit answer to this question. Reaction systems were devised for kinetic measurements to answer this simple question. At first, pKa values of 15 boronic acids were determined spectrophotometrically at I = 1.0 M and 25 °C: pK a = 6.40 ± 0.06 for 3,5-Cl2PhB(OH)2, 6.62 ± 0.03 for 3,5-(CF3)2PhB(OH)2, 6.95 ± 0.09 for 3,5-Br2PhB(OH)2, 7.04 ± 0.03 for 3-NO2PhB(OH)2, 7.08 ± 0.03 for 3,5-F 2PhB(OH)2, 7.12 ± 0.02 for 2,4-F 2PhB(OH)2, 7.39 ± 0.02 for 4-CF3PhB(OH) 2, 7.50 ± 0.02 for 3-FPhB(OH)2, 7.83 ± 0.02 for 2-FPhB(OH)2, 7.87 ± 0.01 for 3-CF3PhB(OH) 2, 8.11 ± 0.01 for 2-ClPhB(OH)2, 8.14 ± 0.03 for 3-(COOH)PhB(OH)2, 8.15 ± 0.03 for 3-(CH 3CO)Ph(OH)2, 8.20 ± 0.01 for 3-ClPhB(OH) 2, and 8.66 ± 0.05 for 4-FPhB(OH)2. The kinetic results for the reactions of some of these boronic acids with 4-isopropyltropolone clearly show that the rate-determining step is not the interconversion step but the chelate-ring closure step.

    AB - Which of the step is rate determining in the complexation of boronic acid with bidentate ligands, the first trigonal/tetragonal interconversion step or the following chelate-ring closure step ? No one could have ever answered this simple question clearly. In this study, we for the first time gave an explicit answer to this question. Reaction systems were devised for kinetic measurements to answer this simple question. At first, pKa values of 15 boronic acids were determined spectrophotometrically at I = 1.0 M and 25 °C: pK a = 6.40 ± 0.06 for 3,5-Cl2PhB(OH)2, 6.62 ± 0.03 for 3,5-(CF3)2PhB(OH)2, 6.95 ± 0.09 for 3,5-Br2PhB(OH)2, 7.04 ± 0.03 for 3-NO2PhB(OH)2, 7.08 ± 0.03 for 3,5-F 2PhB(OH)2, 7.12 ± 0.02 for 2,4-F 2PhB(OH)2, 7.39 ± 0.02 for 4-CF3PhB(OH) 2, 7.50 ± 0.02 for 3-FPhB(OH)2, 7.83 ± 0.02 for 2-FPhB(OH)2, 7.87 ± 0.01 for 3-CF3PhB(OH) 2, 8.11 ± 0.01 for 2-ClPhB(OH)2, 8.14 ± 0.03 for 3-(COOH)PhB(OH)2, 8.15 ± 0.03 for 3-(CH 3CO)Ph(OH)2, 8.20 ± 0.01 for 3-ClPhB(OH) 2, and 8.66 ± 0.05 for 4-FPhB(OH)2. The kinetic results for the reactions of some of these boronic acids with 4-isopropyltropolone clearly show that the rate-determining step is not the interconversion step but the chelate-ring closure step.

    KW - Boronic acid

    KW - Complexation

    KW - Interconversion

    KW - Kinetics

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    SP - 3355

    EP - 3361

    JO - Inorganica Chimica Acta

    JF - Inorganica Chimica Acta

    SN - 0020-1693

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