Unprecedented hydroxyl radical-dependent two-step chemiluminescence production by polyhalogenated quinoid carcinogens and H2O2

Abstract

Most chemiluminescence (CL) reactions usually generate only onestep CL, which is rarely dependent on the highly reactive and biologically/ environmentally important hydroxyl radicals (•OH). Here, we show that an unprecedented two-step CL can be produced by the carcinogenic tetrachloro-1,4-benzoquinone (also known as p-chloranil) and H2O 2, which was found to be well-correlated to and directly dependent on its two-step metal-independent production of •OH. We proposed that •OH-dependent formation of quinonedioxetane and electronically excited carbonyl species might be responsible for this unusual two-step CL production by tetrachloro-1,4-benzoquinone/H2O2. This is a unique report of a previously undefined two-step CL-producing system that is dependent on intrinsically formed •OH. These findings may have potential applications in detecting and quantifying •OH and the ubiquitous polyhalogenated aromatic carcinogens, which may have broad biological and environmental implications for future research on these types of important species.