Formation constants in C–H hydrogen bonding. 4. Effects of cyano, nitro, and trifluoromethyl substituents in aromatic compounds
作者:John P. Lorand
DOI:10.3998/ark.5550190.p008.827
日期:——
Formationconstants (K eq ) have been measured using 1 H NMR for H‐bond complexes with HMPA in CCl 4 of 35 aromatic compounds variously substituted with cyano, nitro, and trifluoromethyl groups; several compounds contained F and Cl. The three strongly polar groups enhance H‐bonding significantly, usually in the ord er NO 2 > CN > CF 3; all are superior to Cl and F. 1,3,5‐Trinitrobenzene fails to H‐bond
已使用 1 H NMR 测量了 H 键配合物与 HMPA 在 CCl 4 中的形成常数 (K eq ),其中 35 种芳族化合物分别被氰基、硝基和三氟甲基取代;几种化合物含有 F 和 Cl。三个强极性基团显着增强了氢键,通常顺序为 NO 2 > CN > CF 3;均优于Cl和F。1,3,5-三硝基苯完全没有H键;然而,TNT、其叔丁基类似物和三硝基间二甲苯显示出显着的 Keq 值。硝基与 HMPA 的环块方法的共面性,可能是通过分子内 H 键。在一些拥挤的化合物中,支撑效应很明显。
Synthesis and spectral investigations of pyridinium picrate
作者:Athmane Meddour、Abdelkader Azizi
DOI:10.1016/j.molstruc.2016.07.032
日期:2017.1
named phase I and II, this transition was followed by a function of temperature and XRD, is agreement with crystal structure data. In the present investigation, IR and Raman spectroscopy were employed for the identification of the transitionsphase of this dimorphic. Essentially studied by Raman low frequency, the shift, disappearance and appearance of the peaks are used for the determination of the
摘要 本文描述了一种称为“苦味酸吡啶”的结晶化合物的振动光谱。通过 FT-IR 和拉曼光谱将振动光谱测量记录为温度的函数。各种官能团的存在及其振动模式被分配并遵循演变。已经使用DSC分析分析了产生的结晶化合物的稳定性。该晶体由两个对称基团 C 2v 和 P -1 组成,分别命名为 I 相和 II 相,这种转变是温度和 XRD 的函数,与晶体结构数据一致。在本研究中,IR 和拉曼光谱被用于鉴定这种双晶的转变相。基本上由拉曼低频研究,位移,