Influence of the Boron Atom on the Solvatochromic Properties of 4-Nitroaniline-Functionalized Boronate Esters
作者:Katja Hofmann、Stefan Spange
DOI:10.1021/jo300530k
日期:2012.6.1
para-substituted phenylboronic acids [R2–C6H4–B(OH)2; R2 = −OCH3, −CH3, −H, −Br, −CHO, −NO2, −B(OH)2], and the solvatochromic properties of these esters are investigated in 33 solvents of different polarity. To interpret the solvent effects, the established linear solvation energy (LSE) multiparameter equations of Kamlet–Taft and the improved Catalán scales are used. Although the boron atom is separated
对位与外围1,2-和1,3-二醇官能团[硝基苯胺衍生物ø 2 N-C 6 H ^ 4 -NR 1 -CH 2 CH(OH)CH 2 OH; O 2 N-C 6 H 4 -NR 1 -CH(CH 2 OH)2;共价键合在氨基上的R 1 = -H,-CH 3 ]被各种对位取代的苯基硼酸[R 2 -C 6 H 4 -B(OH)2酯化。R 2 = -OCH 3,-CH分别在33种极性不同的溶剂中研究了3,-H,-Br,-CHO,-NO 2,-B(OH)2的溶剂溶变色性质。为了解释溶剂效应,使用了建立的Kamlet-Taft线性溶剂化能量(LSE)多参数方程式和改进的Catalán标度。尽管硼原子与实际发色团被两个或三个sp 3-杂化碳原子隔开,但溶剂作用是给体,溶剂化作用对硝基苯胺单元具有显着的正溶剂化变色作用(R 1 = -CH 3)在硼原子上。取代基R 2对系数b的影响根据Kamlet-Taf