Heterocyclic light-driven rotary molecular motors

Abstract

Controlling motion of molecules at the nanoscale has been an aspiration for scientists for many years. The rise of molecular machines over the past two decades has shown that it is possible to achieve this goal, and for this the 2016 Nobel Prize in Chemistry was awarded to researchers in this field. Light-driven rotary molecular motors, first developed in 1999 by Feringa and co-workers, are able to continuously rotate in a single direction when irradiated with light. This unidirectional rotation is a motion used in many machines that we rely on today, for example the motion of the wheels on a bicycle. Over the years, the exact mechanism of molecular motors has been elucidated, and we better understand how to tune their rotational properties, such as speed and efficiency. However, there are some challenges that must be addressed before light-driven molecular motors can find utility beyond scientific research; they are typically powered by high energy UV light, which is not ideal for many applications. In addition, they are typically inefficient – only absorbing up to 20% of the light shining on them – and it can be difficult to synthesise them on a large scale. The research outlined in this thesis aims to address these challenges through the use of heterocyclic motor scaffolds. Additionally, this thesis intends to inform the reader about light-driven rotary molecular motors in general, focussing on the specific design principles that can be used to tune their rotational properties, and detailing how they are studied in our labs.