Electromeric effect of substitution at 6 th position in 2-(Furan-2-yl)-3-hydroxy-4 H-chromen-4-one (FHC) on the absorption and emission spectra
作者:MANISHA BANSAL、RANBIR KAUR
DOI:10.1007/s12039-015-0786-1
日期:2015.3
the electromeric effects of substitution at 2nd and 6th positions on the 2–3 double bond in ‘C’ ring are similar but the effect on the double bond of 4-carbonyl group is opposite. It has been found that the substitution at 2nd position changes mainly the electron density directly at the 4-carbonyl group and substitution at 6th position changes the electron density of the ‘C’ ring, changing the overall
五个3-羟基色酮(3HC),即2-(呋喃-2-基)-3-羟基-4 H-铬烯-4-酮(FHC)及其四个衍生物,分别取代-CH 3,-OH,-由其相应的2'-羟基苯乙酮和呋喃-2-羧醛合成第6位的NO 2和-Cl 。通过解释它们在环己烷,乙腈和甲醇中的吸收光谱,可以确定所有这些3-羟基色酮(3-HCs)的各种光谱跃迁。已经表明,在“ C”环的2–3双键的第2和第6位的取代的电离效应相似,但对4-羰基双键的取代作用相反。已经发现2处的取代nd位主要改变直接在4-羰基上的电子密度,第6位取代取代改变'C'环的电子密度,改变分子的整体偶极矩,进而改变4位的电子密度。 -羰基。发射光谱研究表明,在第6位被吸电子基团(如NO 2)和给电子基团(如-CH 3和-OH)取代,偶极矩的增大和减小分别使极性溶剂中的N *状态稳定和不稳定。 已经合成了五个3-羟基色酮,并指定了它们的吸收带。发射光谱研究表明,在第