Aromatic Bridged Bis(triphenylamine) Cascade Assembly Achieved Tunable Nanosupramolecular Morphology and NIR Targeted Cell Imaging.

Possessing four cationic pyridium groups, phenyl-bridged bis(triphenylamine) derivatives (G1, G2) were encapsulated by cucurbit[8]uril (CB[8]) at a 1:2 stoichiometry to form the network-like organic two-dimensional nanosheet, which could efficiently enhance the near-infrared (NIR) luminescence and companies with a red-shift from 750 to 810 nm for G1. Benefiting from the supramolecular multivalent interaction, α-cyclodextrin modified hyaluronic acid (HACD) and G1/CB[8] formed nanoparticles to further enhance NIR luminescence behaviors. Compared with the short rigid aromatic bridged bis(triphenylamine) derivative (G2), the supramolecular assembly derived from G1 with long flexible cationic arms gives a larger Stokes shift, which further coassembles with the phosphorescent bromophenylpyridinium derivative/CB[8] pseudorotaxane, leading to efficient phosphorescent resonance energy transfer (PRET). Especially, the nanoparticle showed delayed NIR fluorescence under 308 nm light excitation with an ultralarge Stokes shift up to 502 nm, which was successfully applied in targeted NIR cell imaging.

Efficient artificial light-harvesting systems based on aggregation-induced emission in supramolecular gels.

Based on a new designed acyl hydrazone gelator (G2), we developed a supramolecular organogel in glycol with two different hydrophobic fluorescent dyes, namely rhodamine B (RhB) and acridine red, as acceptors. Both the G2@gel-RhB and G2@gel-acridine red systems showed high levels of energy-transfer efficiency and high fluorescence quantum yields.

A new strategy for constructing artificial light-harvesting systems: supramolecular self-assembly gels with AIE properties.

An artificial light-harvesting system (ALHS) has been designed and constructed based on supramolecular organogels made of a simple hydrazide-functionalized benzimidazole derivative (HB), as well as the fluorescent dye rhodamine B (RhB). RhB acted as a good acceptor to realize the energy-transfer process with good efficiency based on a HB/RhB assembly, which showed considerable fluorescence resonance energy transfer (FRET) efficiency of 53% for the energy transfer process. Remarkably, the obtained system showed superior color conversion abilities, converting blue light into orange light. By properly tuning the donor to acceptor ratio, bright orange light emission was achieved with a high fluorescence quantum yield of 35.5%. This system exhibited promise for applications relating to visible-light photo-transformation.