在高达160°C的温度和高达10 mol L -1的NaOH浓度下研究了26种不同的季铵基(QA)的碱稳定性目的是为选择碱性燃料电池中氢氧化物交换膜的官能团和在碱性条件下稳定的离子液体阳离子提供基础。除芳香族阳离子外,大多数QA均表现出出乎意料的高碱性稳定性。发现β-质子对亲核攻击的敏感性远低于先前的建议,而苄基,附近的杂原子或其他吸电子物种的存在则显着促进了降解反应。循环QA被证明是异常稳定的,在所选条件下,基于哌啶的6-氮杂-螺并[5.5]十一烷具有最高的半衰期。本文提供的绝对和相对稳定性与文献数据相反,差异归因于溶剂对降解的影响。
Dealkylation of quaternary ammonium salts by thiolate anions: A model of the cobalamin-independent methionine synthase reaction.
作者:Ellen Hilhorst、Tjoe B.R.A. Chen、Atef S. Iskander、Upendra K. Pandit
DOI:10.1016/s0040-4020(01)85267-4
日期:1994.1
The reactions of thiolate ions derived from thiophenol and homocysteine with substituted quaternary ammonium salts result in alkyl transfer from nitrogen to sulfur. A radical mechanism for this transalkylation, accounts for the reactivity pattern of the substrate salts. In a model study of the cobalamin-independent methionine synthase reaction, 5,5,6,7-tetramethyl-5,6,7,8-tetrahydropteridinium salt
衍生自硫酚和高半胱氨酸的硫醇根离子与取代的季铵盐的反应导致烷基从氮转移到硫。这种烷基转移的自由基机理解释了底物盐的反应模式。在不依赖钴胺素的蛋氨酸合酶反应的模型研究中,可以将5,5,6,7-四甲基-5,6,7,8-四氢opter啶鎓盐(25)视为天然辅酶5的模型。使CH 3 H 4-叶酸盐(1)与高半胱氨酸的硫醇盐反应,结果观察到蛋氨酸的形成具有良好的产率。这些结果表明,在酶促过程中,N(5)-CH 3 N(5)与亲电试剂或质子在活性位点的配位可激活甲基键的甲基键。
Synthesis, Characterization, and Reactivity of Thermally Stable Anhydrous Quaternary Ammonium Fluorides
The synthesis and properties of a new class of anhydrous quaternary ammonium fluorides, based on the rigid skeleton azabicyclo[2.2.2]octane, is described. Compounds 2a–d were easily prepared by passing the corresponding ammonium iodides over fluoride-based resin followed by drying their hydrated form at 100 or 140 °C under reduced pressure. The stability (experimental and theoretical study), solubility
<i>O</i>-Trifluoromethylation of Phenols: Access to Aryl Trifluoromethyl Ethers by <i>O</i>-Carboxydifluoromethylation and Decarboxylative Fluorination
作者:Min Zhou、Chuanfa Ni、Zhengbiao He、Jinbo Hu
DOI:10.1021/acs.orglett.6b01779
日期:2016.8.5
A new strategy for the synthesis of aryl trifluoromethyl ethers (ArOCF3) by combining O-carboxydifluoromethylation of phenols and subsequent decarboxylativefluorination is reported. This protocol allows easy construction of functionalized trifluoromethoxybenzenes and trifluoromethylthiolated arenes (ArSCF3) in moderate to good yields. Moreover, it utilizes accessible and inexpensive reagents sodium
The rapid and efficient synthesis of 1-alkylquinuclidinium (1-alkyl-1-azabicyclo[2.2.2]octane) and 1-alkyl-4-aza-1-azoniabicyclo[2.2.2]octane iodides are described. The products were characterized by 1H NMR spectra and elemental analysis.
Salts with titanyl and vanadyl phthalocyanine radical anions. Molecular design and effect of cations on the structure and magnetic and optical properties
作者:Dmitri V. Konarev、Alexey V. Kuzmin、Salavat S. Khasanov、Mikhail S. Batov、Akihiro Otsuka、Hideki Yamochi、Hiroshi Kitagawa、Rimma N. Lyubovskaya
DOI:10.1039/c7ce01918a
日期:——
radical anion salts of titanyl (TiIVOPc) and vanadyl (VIVOPc) phthalocyanines and nine new salts of these phthalocyanines are discussed. Different synthetic approaches for the preparation of these salts are presented, and the effect of the size and shape of counter cations on the crystal structures of the salts and consequently their magnetic and optical properties are considered. The TiIVO(Pc˙3−)}˙− radical
金属酞菁的自由基阴离子盐已提供了一种新的化合物家族,这些化合物可能具有广阔的光学,磁性和导电性能。仅在最近获得具有不同金属和轴向取代基的酞菁盐系列时,才在该领域取得实质性进展。在这项工作中,我们总结了有关钛氧基(Ti IV OPC)和钒基(V IV OPC)酞菁自由基阴离子盐的最新结果,并讨论了这些酞菁的9种新盐。提出了制备这些盐的不同合成方法,并考虑了抗衡阳离子的大小和形状对盐的晶体结构的影响,并因此考虑了它们的磁性和光学性质。TiIV O(PC 3- )}˙ -自由基阴离子具有小号在PC = 1/2旋3-大环化合物,而V IV O(PC 3- )}˙ -自由基阴离子有两个小号= 1/2在PC 3-大环和中心V IV原子上自旋。因此,可以比较金属酞菁具有不同磁态的同构化合物的磁性。我们还讨论了还原对带负电的钛氧基和钒基酞菁的分子结构以及光学和磁性的影响。