BORIC-ACID COMPLEXES OF PHENOLIC-ACIDS

被引：14

作者：

BELL, CF

GALLAGHER, BC

LOTT, KAK

SHORT, EL

WALTON, L

机构：

[1] Department of Chemistry, Brunel University, Uxbridge

来源：

POLYHEDRON | 1991年 / 10卷 / 06期

关键词：

D O I：

10.1016/S0277-5387(00)83620-7

中图分类号：

O61 [无机化学];

学科分类号：

070301 ; 081704 ;

摘要：

The complexation between boric acid and the three phenolic carboxylic acids, 3,4-dihydroxybenzoic, caffeic and chlorogenic acids, has been examined spectroscopically and this has established that a 1:1 complex is formed in each case. With the first two acids, there is also evidence of a 2:1 complex being formed at high acid to B ratios. Equilibrium constants have been calculated from B-11 NMR spectra of mixtures for the equation for the formation of the 1:1 complex: B + H2A- = BA2- + H3O+. Conditions in which aerial oxidation of the organic acids occurs have been studied by ESR and UV spectroscopy. The presence of boron stabilizes the acids towards oxidation to free radicals and also retards the rate at which the radicals, when formed, are oxidized further to semiquinones.

引用

页码：613 / 618

页数：6

共 16 条

[1] ELECTRON-SPIN RESONANCE STUDIES OF STRUCTURE AND CONFORMATION IN ANION RADICALS FORMED DURING AUTOXIDATION OF HYDROXYLATED COUMARINS [J].