Krishnan Sumesh Babu, Gopidas Karical Raman
Photosciences and Photonics Section, Chemical Sciences and Technology Division, CSIR-National Institute for Interdisciplinary Science and Technology, Trivandrum, 695 019, India.
Academy of Scientific and Innovative Research (AcSIR), New Delhi, 110001, India.
Chemistry. 2017 Jul 18;23(40):9600-9606. doi: 10.1002/chem.201701123. Epub 2017 Jun 27.
Supramolecular chirality was observed in a charge-transfer (CT) complex formed by self-assembly of β-cyclodextrin-linked pyrene and adamantane-linked pyromellitic diimide in water. In the complex, the pyrene-pyromellitic diimide CT interaction is reinforced several-fold by the strong β-cyclodextrin-adamantane inclusion binding interaction, as confirmed by H NMR, absorption, fluorescence and isothermal titration calorimetry studies. The CT complex exhibited high stability, as inferred from the temperature-dependent absorption and NMR studies. The CT absorption band exhibited a positive Cotton effect indicative of supramolecular chirality for the complex. Twisted fibres were observed in TEM, AFM, and SEM experiments. A mechanism involving synergistic binding interactions leading to 2D sheets, followed by twisting of the sheet, is proposed for the formation of twisted fibres. This system offers a chance to investigate a combination of supramolecular CT and supramolecular chirality and explore their synergistic effects.
在水中，由β-环糊精连接的芘和金刚烷连接的均苯四甲酸二酰亚胺自组装形成的电荷转移（CT）复合物中观察到了超分子手性。在该复合物中，芘-均苯四甲酸二酰亚胺CT相互作用通过强β-环糊精-金刚烷包合结合相互作用增强了几倍，这通过1H NMR、吸收、荧光和等温滴定量热法研究得到证实。从温度依赖性吸收和NMR研究推断，CT复合物表现出高稳定性。CT吸收带表现出正的科顿效应，表明该复合物具有超分子手性。在透射电子显微镜（TEM）、原子力显微镜（AFM）和扫描电子显微镜（SEM）实验中观察到了扭曲的纤维。提出了一种机制，即协同结合相互作用导致二维片层形成，随后片层扭曲，从而形成扭曲的纤维。该系统为研究超分子CT和超分子手性的组合并探索它们的协同效应提供了一个机会。
