The role of substituents on resonance assisted hydrogen bonding (RAHB) vs. intermolecular hydrogen bonding is highlighted in known arylhydrazones of active methylene compounds (AHAMCs) and in their new representatives – (E/Z)-2-(2-(para-substitutedphenyl)hydrazineylidene)-N,N-diethyl-3-oxobutanamides (–C₂H₅, –H, –COOH, –CN). The strength of the H-bond depends on the attached functional groups to both the active methylene fragment and the aromatic moiety of the AHAMC. For instance, attachment of the strong electron donor group –N(C₂H₅)₂ (σ_p = −0.72) to the active methylene fragment of AHAMC allows to isolate this class of compounds without RAHB but with strong intermolecular H-bonds, which are the first examples reported herein.

中文翻译：

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取代基在共振辅助氢键与分子间氢键之间的作用

取代基在共振辅助氢键（RAHB）与分子间氢键上的作用在已知的活性亚甲基化合物（AHAMCs）芳基hydr及其新的代表体-（E / Z）-2-（2-（对-取代苯基）中得到强调）（亚肼基）-N，N-二乙基-3-氧代丁酰胺（–C ₂ H ₅，–H，–COOH，–CN）。H键的强度取决于与活性亚甲基片段和AHAMC的芳族部分连接的官能团。例如，强电子给体基团–N（C ₂ H ₅）₂（σ_p＝ -0.72）至AHAMC的活性亚甲基片段允许分离出没有RAHB但具有强分子间H键的这类化合物，这是本文报道的第一个实例。