Light‐Harvesting Fluorescent Supramolecular Block Copolymers Based on Cyanostilbene Derivatives and Cucurbit[8]urils in Aqueous Solution

A novel system of light‐harvesting supramolecular block copolymers (SBCPs) in water is demonstrated. To realize cucurbit[8]uril (CB[8])‐based SBCPs generating artificial light‐harvesting in water, finely color‐tuned supramolecular homopolymers (SHPs) comprising CB[8] host and different cyanostilbene guests (named as B, G, Y, and R) emitting blue, green, yellow, and red fluorescence are first synthesized and characterized, respectively. Light‐harvesting SBCPs with mixed guest emitters are then simply produced by mixing blue and red‐emitting SHPs according to the dynamic host–guest exchange interaction. The light‐harvesting SBCPs show highly efficient energy transfer from B (donor D) to R (acceptor A) attributed to the D/A proximity and parallel orientation of their transition dipoles secured in the block copolymer structure. It is comprehensively shown that cyanostilbene/CB[8]‐based fluorescent SBCPs represent a novel and fascinating class of eco‐friendly artificial light‐harvesting system. According to the dynamic exchange features of cucurbit[8]uril (CB[8]) hosts and cyanostilbene guests, water‐soluble, highly luminescent, and efficiently light‐harvesting cyanostilbenes/CB[8]‐based supramolecular block copolymer (SBCP) nanobundle systems are successfully materialized. The SBCPs in water show great light‐harvesting performance due to energy donor/acceptor proximity and parallel orientation of their transition dipoles secured in the block copolymer structure.