Aggregation-induced emission properties of pyridyl-containing tetra-arylethenes.

Tetra-arylethene is one of the most important aggregation-induced emission (AIE) fluorophores. The electronic effect usually plays a vital role in their optical properties. However, the relationship between AIE property and electronic effect in the same fluorophore is rarely studied. Here, we designed and synthesized a series of pyridyl-containing tetra-arylethenes, whose electronic densities could be easily adjusted by the N-oxide or N-methylation of their pyridyl moieties. The optical data of these compounds at aggregation in different solvent systems or solid state exhibited obviously different AIE properties compared with the classic AIE-active tetraphenylethene (TPE).