Singlet Molecular Oxygen

Meeting the desire for a comprehensive book that collects and curates the vast amount of knowledge gained in the field of singlet oxygen, this title covers the physical, chemical and biological properties of this reactive oxygen species and also its increasingly important applications across chemical, environmental and biomedical areas.The editors have a long and distinguished background in the field of singlet oxygen chemistry and biomedical applications, giving them a unique insight and ensuring the contributions attain the highest scientific level.The book provides an up to date reference resource for both the beginner and experienced researcher and crucially for those working across disciplines such as photochemistry, photobiology and photomedicine.

This book presents the fundamentals and the state of the art of the photophysics of molecular oxygen. The author examines optical transitions between the lowest-lying electronic states in molecular oxygen and how these transitions respond to perturbation, either from an organic molecule or from the plasmon field of a metal nanoparticle. We live on a planet filled with light and oxygen. The interaction between these two components forms the basis of excited state chemistry spanning the fields of synthetic organic chemistry, materials chemistry, molecular biology, and photodynamic treatment of cancer. Still, the fundamental ways in which oxygen is affected by light is an active subject of research and is continually being developed and rationalized. In this book, readers will learn that singlet oxygen, the excited state of oxygen that exhibits unique chemical reactivity, can be selectively made via direct optical excitation of oxygen in a sensitizer-free system. Readers will also discover that this approach can perturb living cells differently depending on the singlet oxygen “dose”.

Singlet Oxygen, the lowest electronically excited state of molecular oxygen, is highly reactive and involved in many chemical and biological processes. It is one major mediator during photosensitization, which has been used by mankind since ancient times, even though the mechanisms behind it were understood only about half a century ago. The combination of high reactivity and very long natural lifetime allows for direct optical detection of singlet oxygen and its interactions using its characteristic phosphorescence at around 1270 nm. Since this emission is very weak, optical detection was technically very challenging for a long time. Therefore, even today, most laboratories only exploit the high reactivity to observe the interaction with sensor molecules, rather than singlet oxygen emission itself. However, in recent years highly sensitive optical detection was developed, the authors being major contributors. This book is dedicated to the detection of singlet oxygen, discussing possibilities, pitfalls and limits of the various methods with a special focus on time-resolved phosphorescence and the kinetics of singlet oxygen generation and decay including involved and related processes, discussing investigated systems with various complexity from solutions over in vitro to in vivo. The long-standing paradigm that singlet oxygen phosphorescence is a benchmark for detection systems rather than an option for process observation is still ubiquitous and this book hopes to contribute in overcoming this still prevailing bias.