Realization of Stacked-Ring Aromaticity in a Water-Soluble Micellar Capsule

Stacked-ring aromaticity arising from the close stacking of antiaromatic pi-systems has recently received considerable attention. Here, we realize stacked-ring aromaticity via a rational supramolecular approach. A nanocapsule composed of bent polyaromatic amphiphiles was employed to encapsulate several antiaromatic norcorrole Ni(II) complexes (NCs) in water. The resulting micellar capsules display high stability toward heating and concentration change. The encapsulation resulted in the appearance of a broad absorption band in the near-infrared region, which is characteristic of norcorroles with dose face-to-face stacking. Importantly, a meso-isopropyl NC, which does not exhibit pi-stacking even in a concentrated solution or the crystalline phase, adopted pi-stacking with stacked-ring aromaticity in the supramolecular micellar capsule.

Automated summary

In this study, stacked-ring aromaticity was achieved using a supramolecular approach. A nanocapsule was used to encapsulate antiaromatic complexes, resulting in stable micellar capsules with broad absorption bands. Notably, a non-pi-stacking complex showed pi-stacking behavior in the supramolecular micellar capsule.