Contribution of the intramolecular hydrogen bond to the shift of the pKa value and the oxidation potential of phenols and phenolate anions
作者:Daisuke Kanamori、Atsushi Furukawa、Taka-aki Okamura、Hitoshi Yamamoto、Norikazu Ueyama
DOI:10.1039/b419361j
日期:——
non-hydrogen bonded references. The presence of intramolecular hydrogen bonds was established through the crystallographic analysis and/or (1)H NMR spectroscopic results. Intramolecular NHO(phenol) hydrogen bonds shift the pK(a) of the phenol to a more acidic value. The results of cyclic voltammetry show that the intramolecular OH...O=C hydrogen bond negatively shifts the oxidation potential of the phenol
分子内OHO [双键,长度为m-C]氢键酚,2-HO-C6H2-3,5-(t-Bu)2-CONH-t-Bu(1-OH),2-HO-C6H2 -5-t-Bu-1,3-(CONH-t-Bu)2(2-OH)和2-HO-C6H2-3,5-(t-Bu)2-NHCO-t-Bu(4-合成OH,并以分子内NHO(氧阴离子)氢键的四乙基铵盐(-1O-(NEt4 +),2-O-(NEt4 +)和4-O-(NEt4 +))制备其酚酸根阴离子。合成了4-HO-C(6)H(2)-3,5-t-Bu(2)-CONH-t-Bu(3-OH)及其酚酸根阴离子3-O-(NEt4 +)非氢键参考。通过晶体学分析和/或(1)1 H NMR光谱结果确定了分子内氢键的存在。分子内NHO(苯酚)氢键将苯酚的pK(a)移至更酸性的位置。循环伏安法的结果表明,分子内的OH ... O = C氢键使苯酚的氧化电位负移。相反,分子内NHO(氧阴