One-Dimensional Double Helical Structure and 4-Fold Type [2 + 2] Interpenetration of Diamondoid Networks with Helical Fashion

We have prepared unique homochiral structures by the self-assembly of a modified amino acid derivative (terephthaloylmonoalanine, L-TMA) with metal ions such as Zn(II) and Cd(II). An L-TMA ligand and Zn(II) ions formed a left-handed, homochiral, double helical chain. However, while L-TMA and Cd(II) ions topologically formed a diamondoid Cd-L-TMA network with 4-fold type [2 + 2] interpenetration, Cd-L-TMA can be morphologically considered as a three-dimensional network of left-handed, double helices. The double helical structure of Zn-L-TMA originated from the self-assembly of individual helical chains by hydrogen bonds and π−π interactions, whereas the double helical structures of Cd-L-TMA were observed in an interpenetrating diamondoid net.

本研究通过修饰氨基酸衍生物对苯二甲酰单丙氨酸（terephthaloylmonoalanine, L-TMA）与锌(II)、镉(II)等金属离子的自组装，制备得到独特的同手性结构。L-TMA配体与锌(II)离子可形成左手同手性双螺旋链。当L-TMA与镉(II)离子结合时，拓扑上可构筑出具有四重[2+2]互穿特征的类金刚石型Cd-L-TMA网络；而从形貌维度来看，Cd-L-TMA可被视作由左手双螺旋构成的三维网络。Zn-L-TMA的双螺旋结构源于单条螺旋链通过氢键与π-π相互作用实现的自组装，Cd-L-TMA的双螺旋结构则存在于互穿类金刚石骨架中。