They are relatively inert photochemically unless the nitrogen atom is substituted by an acyl group, in which case a rich photochemistry is observed. We have been exploring the mechanism and synthetic applications of this photochemistry. One method of permanent removal of pollutants from the environment is their photolysis to innocuous products. We are exploring a process which involves the destruction of volatile organic molecules present as contaminants in air by irradiation of a catalyst with ultra-violet light. In this project we are exploring the use of supercritical fluids as media for photochemical reactions.
Supercritical fluids act as low density solvents for organic compounds.
For the photochemist they have two interesting properties. The dielectric constant, and hence polarity of the medium can be varied dramatically by changing the pressure and hence the density of the fluid. Rate constants for diffusion in the fluids are also much faster than in condensed media so that bimolecular processes can become more competitive with unimolecular excited state decay or reaction. We are probing how these properties can be used to control or change the photochemical reactivity of organic compounds.