以对映体纯的形式制备了一系列含有反式-1,2-二氨基环己烷(DACH)亚基以及芳烃和低聚乙二醇的间隔基的新的手性大环化合物。的大环化合物的四个已通过X射线晶体学,从而揭示分子内N-H···Ñ氢键和关于所述构象变化的一致的模式ñ -benzylic键。通过CDCl 3中的1 H NMR光谱发现,大多数大环化合物可区分扁桃酸(MA)的对映异构体。在所测试的一系列大环化合物中,对映二歧化是由(i)元促进的-关于芳烃间隔基的键合几何形状,(ii)存在萘而不是亚苯基衍生的芳烃间隔基,和(iii)增加低聚乙二醇桥的长度。1个用光学纯的MA样品进行1 H NMR滴定,并将数据拟合至同时的1:1和2:1结合模型,得出一些大环化合物与MA对映异构体之间2:1结合常数的估计值。在几种情况下,MA:大环配合物的NOESY光谱分别显示与大环的胺和羧酸基团相邻的质子与MA对映体之间的分子内相关差异,从而证明了非对映
Selective Retention of Methanol over Ethanol by a Cyclen-Based Cryptand/Copper(II) Complex
摘要:
A cyclen-based cryptand (2) was prepared in a two-step synthesis from dioxocyclen. When a Cu(CF3SO3)(2) complex with 2 was prepared in methanol, the 2/Cu(CF3SO3)(2) complex incorporated one methanol in the cavity formed by the diethyleneoxy unit and the NH group of the cyclen. When prepared in ethanol, the 2/Cu(CF3SO3)(2) complex similarly incorporated one ethanol. Cold electrospray ionization mass spectrometry (CSI-MS) of the 2/Cu(CF3SO3)(2)/alcohol complexes selectively retains methanol over ethanol under CSI-MS conditions.
Kingdom for a lead crown: A crown‐ether‐like, open PbII framework is generated from its phtotochromic precursor by a leaching approach. The dual and bimodalemissions are successfully realized by intercalation of the different Ln3+ hydrates into the hollow PbII frameworkbased on a guest‐driven approach (see graphic).