Photochromism - Logic and Biologic Approaches

Abstract: Photochromism is the light-induced colour change of molecules called photo-chromic compounds. The isomerisation causes changes in the electronic properties of the molecules and rearrangements of bonds which can be used in many more applications than the observed colour change. In this thesis photochromism has been used in molecular logic as well as biologic applications. In molecular logic the photochromic compounds have been used to realise logic gates which function in the same way as the traditional logic devices based on silicon found in any computer, the difference being that optical signals are used rather than electronic. The design and interpretation of a molecular memory and logic gates are presented. In biology, where often a binary on-off process is desired, DNA-binding of photochromic spiropyrans as well as their pH-dependent behaviour in aqueous solution are presented. Together these investigations are demonstrated as examples of how to use photochromism in logic as well as biologic applications.