Preparation of a Multicarbazole-Based Nanocapsule Capable of Largely Modulating Guest Spectroscopic Properties in Water.

A nanocapsule composed of multiple carbazole panels (ca. 12 panels) was quantitatively generated from bent carbazole-based amphiphiles in water. Unlike previously reported macrocycles and coordination cages bearing several carbazole panels, the resultant nanocapsule displays enhanced emissivity and improved electrochemical stability as compared with the monomeric amphiphile. The spectroscopic properties of substituted coumarin and boron-dipyrromethene dyes can be modulated upon encapsulation by the nanocapsule in water. In the cavity, a highly blue-shifted absorption band is observed from largely twisted coumarin dyes and two absorption bands are found from boron-dipyrromethene dimers stacked in an unusual L-shaped fashion. Moreover, the encapsulated dimers exhibit unique excimer-like emission.