Chemiluminescence of 3,3′,4,4′-tetrahydro-1,1′-biisoquinolinium salts

Basic methanolic solutions of 2,2′-dimethyl-3,3′,4,4′-tetrahydro-1,1′-biisoquinolinium iodide (1) chemiluminesce brightly when exposed to oxygen. The first reaction is between base and dication to form a mixture of olefins. These electron-rich olefins are formed by proton removal from, or RO- addition to, the dication and subsequent redox equilibria. The olefins react with ground state O₂ by another redox reaction involving ROH as catalyst. Several oxygenated products are formed and several emission peaks appear. One correlation between a product and an emission peak is possible.