Synthetic Nanomachines Driven Through Metal-Ligand Exchange Reactions

The overall aim of this research is to create synthetic machines that are a few nanometres in size. To put that into context, the average width of a human hair is about 10,000 nanometres! Fortunately, it is relatively easy to make objects of this size as this is the domain of single small molecules, and synthetic chemists (such as those which make pharmaceuticals) have been making these for nearly 200 years. However, what is significantly more challenging at this scale is controlling motion. In contrast to the macroscopic world around us where objects remain stationary until a force is applied, molecular scale objects are subject to constantly random movement, an effect known as Brownian motion. Guidance (and reassurance!) is at hand, as Nature has built up a vast array of nanomachines it uses for lots of different biological processes from cellular transport to even making proteins. In all of these cases, biological nanomachines use architectures to restrict motion to a single dimension, reminiscent of the way a train uses a track to go forward or backward, but never side to side. Similarly, we aim to prepare a track molecule and investigate the motion of a platinum-based molecular fragment along it. Platinum has been chosen as it can simultaneously act as both a glue and grease (!) by binding the fragment to the track whilst facilitating motion along it. Eventually we would like to use such nanomachines to 'pull' drug molecules into cells that normally would not be able to enter.