Efficient Synthesis of Calix[6]tmpa: A New Calix[6]azacryptand with Unique Conformational and Host–Guest Properties
作者:Xianshun Zeng、David Coquière、Aurélie Alenda、Eva Garrier、Thierry Prangé、Yun Li、Olivia Reinaud、Ivan Jabin
DOI:10.1002/chem.200600278
日期:2006.8.16
study indicated that the ligand, as well as its complexes, adopt a major flattened cone conformation that is the opposite of that observed with the previously reported calix[6]cryptands. Characterization of the monoprotonated derivative 11H(+) by X-ray diffraction also revealed the presence of a 1,3-alternate conformation, which is the first example of its kind in the calix[6]arene family. This conformer
通过有效的[1 + 1]大环化反应合成了新的C(3v)-对称杯[6]氮杂密码子,即杯[6] tmpa(11)。值得注意的是,采用线性和会聚的合成策略均会产生同样好的总产量。与经典的三(2-吡啶基甲基)胺(tmpa)衍生物不同,杯杯[6] tmpa表现为单个质子海绵,似乎不愿进行多质子化。它也可以作为铵离子的良好宿主。有趣的是,它以协作的方式牢固地结合了钠离子和中性客体分子,例如尿素,酰胺或醇。一项(1)H NMR研究表明,该配体及其配合物均具有主要的扁平圆锥构象,与先前报道的杯[6] cryptands观察到的相反。通过X射线衍射对单质子化衍生物11H(+)进行表征,还发现了1,3-交替构象的存在,这是其在杯[6] arene家族中的第一个例子。该构象异构体也可能以次要形式存在于溶液中。由杯芳烃骨架上的多芳族tmpa帽诱导的重要共价约束,以及相反地从杯芳烃核心到tmpa部分,是该宿主独特构象和化学性质的可能基础。