Synthesis of new quinolizinium-based fluorescent compounds and studies on their applications in photocatalysis.

Quinoliziniums, cationic aromatic heterocycles bearing a quaternary bridgehead nitrogen, have been widely used as fluorescent dyes, DNA intercalators, ionic liquids etc. A library of new quinolizinium compounds was synthesized from quinolines and internal alkyne substrates in up to 65% isolated yields. Systematic studies of their photophysical properties were conducted. The quinoliziniums have been used in three visible-light-induced photocatalysis reactions with good yields.