Chemical tools for the generation and detection of singlet oxygen

Growing evidence indicates intermediacy of singlet dioxygen (O-1(2)) in a variety of pathophysiological processes. O-1(2) has also found great utility of destructive actions for clinical and environmental applications. However, many details of the molecular mechanisms mediated by O-1(2) remain insufficiently understood. Efforts to elucidate the O-1(2) chemistry have been hampered by the lack of chemical tools capable of generation and detection of O-1(2). In this review, I summarize the recent advances in the development of the chemical tools of O-1(2). This article focuses on two topics. The first part introduces chemical methods for ground-state generation of O-1(2). Designs of the molecular carriers of O-1(2) are also explained. The second part discloses molecular probes of O-1(2). The probes are categorized into three groups, depending on signaling modalities: absorption-based probes, photoluminescent probes, and chemiluminescent probes. Focus is on the molecular design to maximize the signaling actions. Disadvantages of using the probes are also discussed to motivate the future research. I hope that this review will serve as helpful guidance to the exploitation and development of the chemical tools of O-1(2).