物理化学学报 >> 2015, Vol. 31 >> Issue (2): 204-210.doi: 10.3866/PKU.WHXB201412191

热力学，动力学和结构化学 上一篇    下一篇

取代基效应对N-4-取代苯亚甲基苯胺与N-4-取代苯亚甲基环己胺NMR和UV光谱影响的差异性

曹朝暾, 魏佰影, 曹晨忠   

  1. 湖南科技大学化学化工学院, 理论有机化学与功能分子教育部重点实验室, 分子构效关系湖南省普通高等学校重点实验室, 湖南 湘潭 411201
  • 收稿日期:2014-09-24 修回日期:2014-12-19 发布日期:2015-01-26
  • 通讯作者: 曹晨忠 E-mail:czcao@hnust.edu.cn
  • 基金资助:

    国家自然科学基金(21272063, 21072053)和湖南省自然科学基金(14JJ3112)项目资助

Effect of Substituents on the NMR and UV Spectra of N-(4-substituted benzylidene) Anilines and N-(4-substituted benzylidene) Cyclohexylamines

CAO Chao-Tun, WEI Bai-Ying, CAO Chen-Zhong   

  1. Hunan Provincial University Key Laboratory of QSAR/QSPR, Key Laboratory of Theoretical Organic Chemistry and Function Molecule of Ministry of Education, School of Chemistry and Chemical Engineering, Hunan University of Science and Technology, Xiangtan 411201, Hunan Province, P. R. China
  • Received:2014-09-24 Revised:2014-12-19 Published:2015-01-26
  • Contact: CAO Chen-Zhong E-mail:czcao@hnust.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (21272063, 21072053) and Natural Science Foundation of Hunan Province, China (14JJ3112).

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摘要：

合成了N-4-取代苯亚甲基苯胺(1)与N-4-取代苯亚甲基环己胺(2)两个系列化合物, 测定其13C和1H 核磁共振(NMR)化学位移以及紫外(UV)吸收光谱. 定量对比了取代基效应对两个系列化合物CH=N键的13CNMR化学位移δC(C=N)和1H NMR化学位移δH以及UV吸收光谱最大波长能量(vmax)的影响差异. 研究结果表明,对于分子骨架相似的化合物(1)和(2), 取代基效应的作用方式存在多样性: (i)化合物(1)的δC(C=N)、δH以及vmax受到基团的特殊交叉相互作用(Δσ2)的影响显著, 而Δσ2对化合物(2)相应性能的影响很小; (ii)无论化合物(1)还是化合物(2), 取代基场/诱导效应σF和共轭效应σR对δC(C=N)的影响为负相关, 而对δH的影响为正相关, 它们对δC(C=N)和δH的影响正好相反. 另一方面, 场/诱导效应σF对(1)和(2)的δC(C=N)影响重要, 而对它们的δH影响很小; (iii)化合物(1)和(2)的δC(C=N)、δH以及vmax的变化规律, 可分别建立通用方程表达, 其中与CH=N的N原子键连苯基的影响可由指示变量(I)表示, 该苯基对三种性能分别有固定的贡献.

关键词: 苯亚甲基胺, 取代基效应, 核磁共振, 紫外吸收, 基团特殊交叉作用

Abstract:

Two series of compounds: N-(4-substituted benzylidene) anilines (1) and N-(4-substituted benzylidene) cyclohexylamines (2) were synthesized. Their 13C NMR and 1H NMR chemical shifts and their UV absorption spectra were obtained. Compounds (1) and (2) were compared quantitatively to determine the effect of the substituents on the 13C NMR chemical shifts δC(C=N) and the 1H NMR chemical shifts δH of the CH=N bond, and the UV absorption maximum wavelength energies vmax. Our results show that the substituents affect compounds (1) and (2) differently despite them having a similar molecular skeleton. These effects are: (i) a substituent specific cross-interaction effect (Δσ2) that significantly affects the δC(C=N), δH, and vmax of compounds (1) while its effect on the corresponding properties of compounds (2) is limited, (ii) for compounds (1) and compounds (2) the field/induced effect σF and the conjugation effect σR of the substituents negatively affect δC(C=N). However, they positively influence δH and thus both σF and σR showopposite behavior toward δC(C=N) compared with δH. In contrast the field/induced effect greatly affects the δC(C=N) of both (1) and (2) but does not affect their δH, (iii) the regular change in δC(C=N), δH, and the vmax of (1) as well as (2) can be expressed by a general equation in which the effect of the phenyl group attached to the N atom of the CH=N bond can be expressed by a dummy parameter I. The phenyl group has a constant contribution toward these three properties.

Key words: Benzylidene-aniline, Substituent effect, Nuclear magnetic resonance, Ultraviolet absorption, Substituent specific cross-interaction