Cu²⁺ Ion-induced self-assembly of pyrenylquinoline with a pyrenyl excimer formation

Synthesis of a novel pyrene derivative sensor (1) and its intermolecular binding pattern to Cu²⁺ in CH₃CN were investigated. Upon Cu²⁺ binding, the sensor exhibited a strong static excimer emission at 460 nm, along with a weak monomer emission at 388 nm. The excimer emission intensity induced by the Cu²⁺ ion declined as the spacer length between the pyrene and quinolinylamide unit increased. The Cu²⁺ ion-induced self-assembled pyrenyl excimer formation is rationalized by fluorescence experiments and theoretical DFT calculations.