Additivity of Substituent Effects in Aromatic Stacking Interactions
作者:Jungwun Hwang、Ping Li、William R. Carroll、Mark D. Smith、Perry J. Pellechia、Ken D. Shimizu
DOI:10.1021/ja504378p
日期:2014.10.8
predict SEs with an accuracy from ±0.01 to ±0.02 kcal/mol. The additive SEs were consistent with Wheeler and Houk's direct SE model. However, the indirect or polarization SE model cannot be ruled out as it shows similar levels of additivity for two to three substituent systems, which were the number of substituents in our model system. SE additivity also has practical utility as the SEs can be accurately
本研究的目的是通过实验测试静电取代基效应 (SE) 对芳烃堆积相互作用的可加性。使用可以采用偏移面对面芳香堆积几何结构的小分子模型系统评估 SE 的可加性。这些分子扭转平衡的分子内相互作用通过折叠/展开构象平衡的变化进行定量测量。检查了五种不同类型的取代基(CH3、OCH3、Cl、CN 和 NO2),范围从给电子到吸电子。测量了氯仿溶液中 21 个取代芳烃堆积天平和 21 个对照天平的分子内堆积相互作用的强度。观察到的稳定性趋势与添加剂 SE 一致。具体来说,附加 SE 模型可以以 ±0.01 到 ±0.02 kcal/mol 的精度预测 SE。附加 SE 与 Wheeler 和 Houk 的直接 SE 模型一致。然而,不能排除间接或极化 SE 模型,因为它显示了两到三个取代基系统的相似水平的可加性,这是我们模型系统中取代基的数量。SE 可加性也具有实际效用,因为可以准确预测 SE。这应该
Novel dual-functional phthalonitrilemonomers containing a maleimide group were synthesized and characterized. Ortho, meta, and para isomers were obtained and only the meta-isomer can be considered as a low melting phthalonitrilemonomer with a melting point of 107.4°С. Analysis of the dual-curing behavior of monomers showed radical homopolymerization of maleimides followed by phthalonitrile polymerization
合成并表征了具有马来酰亚胺基团的新型双功能邻苯二甲腈单体。获得了邻位,元和对位异构体,只有元-异构体可以被认为是熔点为107.4°C的低熔点邻苯二甲腈单体。单体的双重固化行为分析表明,马来酰亚胺进行自由基均聚,然后进行苯二甲腈聚合,形成异吲哚啉,三嗪和酞菁环结构。研究了通过烯键反应和开环酰胺化反应的两种可选的马来酰亚胺基团共聚过程。在单个分子中双固化马来酰亚胺和邻苯二甲腈片段的方法允许将双马来酰亚胺树脂的优异的固有机械性能与邻苯二甲腈的出色的热氧化稳定性相结合。两个官能团固化后,冲击强度高达11.81 kJ m -2,弯曲强度为108MPa,杨氏模量为4.38GPa。相反,该聚合物体系的T g在空气中高于370°C,T 5%在450°C以上。