AUTHOR=Guo Yan , Han Ying , Chen Chuan-Feng 

TITLE=Construction of Chiral Nanoassemblies Based on Host-Guest Complexes and Their Responsive CD and CPL Properties: Chirality Transfer From 2,6-helic[6]arenes to a Stilbazolium Derivative

JOURNAL=Frontiers in Chemistry

VOLUME=7

YEAR=2019

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2019.00543

DOI=10.3389/fchem.2019.00543

ISSN=2296-2646

ABSTRACT=<p>A couple of water-soluble chiral 2,6-helic[6]arene derivatives <bold><italic>P</italic></bold>-<bold>H1</bold> and <bold><italic>M</italic></bold>-<bold>H1</bold> were synthesized, and they could form 1:1 stable complexes with 4-[(4′-<italic>N, N</italic>-diphenylamino)-styryl]-<italic>N</italic>-methylpyridinium iodide (<bold>G</bold>) in water. Compared with <bold>G</bold>, the host-guest complexes exhibited enhanced fluorescence, which might be attributed to the spatial confinement of <bold>G</bold> and restriction of aggregation-caused quenching (ACQ) effects. Based on the host-guest complexation, the first helic[6]arene-based chiral assemblies were then constructed, and they showed rectangular or hexagonal nanostructures by scanning electron microscopy (SEM) images. Interestingly, the assemblies showed clear mirror-image circular dichroism (CD) and circularly polarized luminescence (CPL) spectra in aqueous solution, revealing a consecutive chirality transfer from the chiral macrocyclic cavities of the hosts to <bold>G</bold>. Moreover, the supramolecular chirality of the assemblies could also show responsiveness to the pH values and temperatures of the system.</p>