AIE active piperazine appended naphthalimide-BODIPYs: photophysical properties and applications in live cell lysosomal tracking.

Piperazine appended naphthalimide-BODIPYs (NPB1-NPB4) exhibiting solvatochromism and aggregation-induced emission with a large Stokes shift (up to 146 nm) have been described. Separation of naphthalimide and BODIPY fluorophores by piperazine in these conjugates creates a donor-acceptor system and induces twisted intramolecular charge transfer, in addition to photoinduced electron transfer. The crucial role of naphthalimide, the alkyl chain length, the piperazine ring, and the solid-state packing on AIE has been extensively investigated by various studies. Superior cell permeability coupled with bio-compatibility of these conjugates offers a unique opportunity for their potential applications in live cell lysosomal tracking.