Final Report Summary - SINOXYGEN (Advancing the Green Chemistry of Singlet Oxygen and Applying it to Synthetic Challenges)
Synthetic chemistry is all about making molecules – molecules that are needed by science and society; such as, medicines, new materials, nanotechnologies, agrochemicals, energy storage devices, biological probes, diagnostic aids, perfumes etc. For many years synthetic chemists have developed tools and technologies to help others build the molecules they need – it is a science at the heart of many other sciences. Today, we urgently need to discover new tools (we call this “developing methodologies”) that are more sustainable. Sustainability is about being clean, green and efficient and about carefully using only renewable resources. In our laboratory, we use oxygen (from the air), visible spectrum light and very tiny amount of a photosensitiser (this can be a natural compound like chlorophyll, rose Bengal etc.) to generate a very reactive (high energy) form of oxygen called “singlet oxygen”. We use the singlet oxygen to initiate the building of three dimensionally complicated molecules from simple and relatively flat starting substrates (that are also very easy to make). The singlet oxygen not only adds its two oxygen atoms to the starting substrate, but initiates a series of reactions that “zip up” the flat linear molecule into a complicated polycyclic 3D molecule that would have required many steps to build up slowly if more traditional chemistry had been used. In other words, we use a green reagent (the singlet oxygen) under efficient green conditions to very rapidly get to our target structures and we hope others can then take our developments and use them to make their desired molecules. We have synthesized a diverse range of molecules using these techniques. We have also developed a very effective and novel photoreactor for running these reactions in continuous flow nebula (clouds). This newly developed technology helps us to scale up the singlet oxygen chemisty so that its products can be made in larger amounts.