A series of heterobicyclic aza/thia-lactams and cryptands incorporating changes in n-alkyl bridging length have been synthesized, characterized, chelated to heavy metals and computationally assessed. Spectroscopic analysis of aza/thia-lactams L1 and L3 revealed multiple conformational isomers, due to rotameric perturbations associated with the amide bond. Correlation spectroscopy on amine cryptands L2 and L4 supported the presence of intrinsic topological chirality, resulting from a preferred orientation of the amine lone pairs in solution. The unique magnetic environments observed in ¹H NMR were attributed to the electron density inside the crypt, which adopt a nephroidal-epicycloid structure with two nitrogen atoms representing the cusps. The major conformational and constitutional isomers for L2 and L4 present in solution were determined to be the in/in pair of enantiomers (R,R and S,S) and confirmed through computational analysis. Application of ligands L1–L4 as heavy metal chelates was addressed using Pb(II), Hg(II), Cd(II) and Ag(I) through NMR spectroscopy and mass spectroscopy.

中文翻译：

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拓扑氮杂/硫杂配体：使用正烷基桥接的输入/输出异构的合成和理论方面

已经合成，表征，结合了重链螯合正构烷基的一系列杂双环氮杂/硫杂-内酰胺和穴状配体，并与重金属螯合并进行了计算评估。氮杂/硫杂-内酰胺L1和L3的光谱分析显示，由于与酰胺键相关的旋转异构体扰动，存在多种构象异构体。胺隐体L2和L4的相关光谱法支持存在固有的拓扑手性，这是由于溶液中胺孤对的优选取向所致。^1中观察到的独特磁环境1 H NMR归因于隐窝内部的电子密度，该隐窝采用一种以两个氮原子代表尖点的螺状-上环摆线结构。为主要构象和结构异构体L2和L4，确定存在于溶液中成为在/于对映异构体（R，R和S，S）的，并证实通过计算分析。通过Pb（II），Hg（II），Cd（II）和Ag（I）通过NMR光谱法和质谱法研究了配体L1-L4作为重金属螯合物的应用。