Two kinds of Schiff bases, 85 samples of N‐(benzylidene)‐anilines (ZBAY) and 83 samples of N‐(phenyl‐ethylene)‐anilines (ZAPEY), were used as model compounds, in which the ZBAY contains 13 compounds with 2‐OH and the ZAPEY contains 35 compounds with 2‐OH (synthesized by this work). The quantitative correlation analysis ultraviolet absorption spectra of ZBAY and ZAPEY were performed, and the effect of intramolecular hydrogen bond on their wave number v_max (cm⁻¹) of the maximum absorption wavelength λ_max (nm) was investigated. The results show that (a) the factors affecting the v_max of ZBAY and ZAPEY are roughly the same, but their intensities are different. (b) The v_max move caused by intramolecular hydrogen bond is all red shift for both ZBAY and ZAPEY, but the red shift value (2,381) of the ZBAY is more than twice than that (850) of ZAPEY. (c) The effect of intramolecular hydrogen bond on v_max is only dominated by the parent structure unit of Schiff base, rather than the substituents in the molecule. For those compounds with the same parent structure unit, their red shift values of v_max are at fixed value, but their red shift values of λ_max are unequal. Generally, the red shift value caused by the intramolecular hydrogen bond is larger for the compound with a larger λ_max value. The above observed phenomena are discussed from the view of molecular coplanarity.

中文翻译：

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分子内氢键对联芳基席夫碱的紫外线吸收的影响

以两种席夫碱为模型化合物，其中85种为N-（亚苄基）-苯胺（ZBAY）和83种N-（苯基-亚乙基）-苯胺（ZAPEY）作为模型化合物，其中ZBAY包含13种化合物2-OH和ZAPEY包含35种含2-OH的化合物（由本工作合成）。进行ZBAY和ZAPEY的定量相关性分析紫外吸收光谱，和分子内氢键的对他们的波数的效果v_最大（厘米^-1的最大吸收波长的）λ_最大（nm）的进行了研究。结果表明（a）影响v _max的因素ZBAY和ZAPEY的总和大致相同，但是强度不同。（b）由分子内氢键引起的v _max移动对于ZBAY和ZAPEY都是红移，但是ZBAY的红移值（2,381）是ZAPEY的红移值（850）的两倍以上。（c）分子内氢键对v _max的影响仅由席夫碱的母体结构单元而不是分子中的取代基决定。对于具有相同母体结构单元的那些化合物，它们的红移值v_最大是在固定的值，但是它们的红移的值λ_最大是不平等的。一般地，所引起的分子内氢键的红移值是具有较大的化合物更大的λ_最大值。从分子共面性的角度讨论了以上观察到的现象。