Regenerative Chemiluminescent Systems

In this doctoral Thesis, the phenomenon of Regenerative Chemiluminescence (RCL) has been reinvestigated. RCL involves the generation of light through an exergonic electron transfer reaction between an oxidized (or reduced) luminophore in its ground state and a reducing (or oxidizing) agent. The intermediate oxidized (or reduced) luminophore is also formed via a chemical reaction with another redox mediator. This mechanism, which is based upon successive electron transfer reactions, allows for the regeneration of the luminophore following the emission of light, thus permitting participation in multiple RCL cycles. Nevertheless, previously documented instances of RCL, spanning from the 1960s to the 1980s, depend on the utilization of potent and hazardous redox agents to achieve excited states, consequently impeding the advancement of this technique. To address this limitation, the current PhD research concentrated on the design and development of innovative RCL luminophores capable of functioning with mild redox mediators. Both fluorescent organic emitters and phosphorescent Pt(II) complex aggregates have been investigated as potential luminophores. Three novel RCL systems have been developed. The first system, employing amino-pyrene derivatives, utilizes oxygen as a mild oxidant to initiate the RCL cycle. The second system, predicated on perylene bisimide luminophores, can operate with dithionite as a mild reducing agent and hydrogen peroxide as the oxidant. The third system demonstrated that the redox-driven supramolecular self-assembly of Pt(II) complexes can be efficiently harnessed to allow light production using mild, even biologically relevant, reducing agents such as NaBH4, ascorbate, or NADH. Furthermore, the previously established stepwise RCL has been evolved into a dissipative chemiluminescent system, termed Chemically Fueled Regenerative Chemiluminescence (CFRCL), wherein the luminophore, oxidant, and reducing agent coexist in solution. In CFRCL, the luminophore mediates the decomposition of the oxidant and the reducing agent and light is emitted as long as both redox fuels are present within the system.