波谱学杂志2017，Vol.34Issue(1)：69-77,9.DOI:10.11938/cjmr20170109
取代基效应对二芳基硝酮CH=N(O)桥基1H NMR化学位移的影响
Substituent Effects on the 1H NMR Chemical Shifts of CH=N(O) Bridge Group in Diaryl Nitrone
摘要
Abstract
A series of substituted diaryl nitrones XArCH=N(O)ArY were synthesized, and their 1H NMR spectra were measured. The 1H chemical shift of the CH=N(O) bridge groups, δH[CH=N(O)], in each compound was determined. The effects of substituents X and Y on δH[CH=N(O)] were investigated quantitatively. A four parameters correlation equation was constructed to model the changes of δH[CH=N(O)] with substituents, yielding a standard error of 0.020. The result indicated that δH[CH=N(O)] in substituted diaryl nitrones are mainly affected by four factors: field/inductive effect (S) of substituent X [σF(X)], conjugative effect of substituent Y [σR(Y)], substituent specific cross-interaction effect between X and Y (Δσ2) and substituent specific crossinteraction effect between X and O- [Δσ2(X-O-)]. Among these factors, the contribution of Δσ2(X-O-)to δH[CH=N(O)] was more than 70%. A comparison of δH[CH=N(O)] in substituted diaryl nitrones to δH(CH=N) of the CH=N bridge group in diaryl Schiff base XArCH=NArY revealed no good linear relationship between δH[CH=N(O)] and δ H(CH=N). Therefore it should be noted that one cannot simply use the change of δH(CH=N) to deduce the change of δH[CH=N(O)] when carrying out organic molecule structure elucidation with NMR spectra.关键词
核磁共振(NMR)/1HNMR化学位移/取代基效应/二芳基硝酮/二芳基希夫碱/基团特殊交叉作用Key words
nuclear magnetic resonance (NMR)/1H NMR chemical shift/substituent effect/diaryl nitrone/diaryl Schiff base/substituent specific cross-interaction effect分类
数理科学引用本文复制引用
曹朝暾,罗青青,曹晨忠..取代基效应对二芳基硝酮CH=N(O)桥基1H NMR化学位移的影响[J].波谱学杂志,2017,34(1):69-77,9.基金项目
国家自然科学基金资助项目(21272063),湖南省教育厅科研资助项目(14C0466)和湖南省自然科学基金资助项目(14JJ3112). （21272063）
