Universal Reaction Mechanism of Boronic Acids with Diols in Aqueous Solution: Kinetics and the Basic Concept of a Conditional Formation Constant

Yuki Furikado, Tomomi Nagahata, Takuya Okamoto, Tomoaki Sugaya, Satoshi Iwatsuki, Masahiko Inamo, Hideo D. Takagi, Akira Odani, Koji Ishihara*

*この研究の対応する著者

研究成果査読

53 被引用数 (Scopus)

抄録

To establish a detailed reaction mechanism for the condensation between a boronic acid, RB(OH)2, and a diol, H2L, in aqueous solution, the acid dissociation constants ({K{{{\rm BL}\hfill \atop {\rm a}\hfill}}}) of boronic acid diol esters (HBLs) were determined based on the well-established concept of conditional formation constants of metal complexes. The pKa values of HBLs were 2.30, 2.77, and 2.00 for the reaction systems, 2,4-difluorophenylboronic acid and chromotropic acid, 3-nitrophenylboronic acid and alizarin red S, and phenylboronic acid and alizarin red S, respectively. A general and precise reaction mechanism of RB(OH)2 with H2L in aqueous solution, which can serve as a universal reaction mechanism for RB(OH)2 and H2L, was proposed on the basis of (a) the relative kinetic reactivities of the RB(OH)2 and its conjugate base, that is, the boronate ion, toward H2L, and (b) the determined pKa values of HBLs. The use of the conditional formation constant, K′, based on the main reaction: [eq found] instead of the binding constant has been proposed for the general reaction of uncomplexed boronic acid species (B′) with uncomplexed diol species (L′) to form boronic acid diol complex species (esters, BL′) in aqueous solution at pH 5-11: [eq found]. The proposed reaction mechanism explains perfectly the formation of boronic acid diol ester in aqueous solution. Using the conditional formation constant (K′) instead of the binding constant allows one to determine a detailed reaction mechanism for the reaction between boronic acids (RB(OH)2) and diols (H2L) in aqueous solution. The proposed mechanism based on thermodynamic and kinetic data explains perfectly the formation of boronic acid diol esters, RB(L)(OH)-.

本文言語English
ページ(範囲)13194-13202
ページ数9
ジャーナルChemistry - A European Journal
20
41
DOI
出版ステータスPublished - 2014 10 1

ASJC Scopus subject areas

  • 触媒
  • 有機化学

フィンガープリント

「Universal Reaction Mechanism of Boronic Acids with Diols in Aqueous Solution: Kinetics and the Basic Concept of a Conditional Formation Constant」の研究トピックを掘り下げます。これらがまとまってユニークなフィンガープリントを構成します。

引用スタイル