He is noted for the invention of fundamental methods to control molecular-level dynamics and entanglement, including strategies to construct rotaxanes, catenanes and molecular knots and some of the earliest synthetic molecular motors, molecular robots and functional nanomachines.
Using mechanically-interlocked molecular architectures he prepared a novel molecular information ratchet[5] that employs a mechanism reminiscent of Maxwell's demon (although it requires an energy input and so does not challenge the second law of thermodynamics).[6] He has developed a rotaxane based photoactive molecular switch with the capability of changing the hydrophobicity of a surface and thus causing small droplets of liquid to move up hill, against the force of gravity.[7] In 2009 he reported the first small-molecule walker-track system in which a 'walker' can be transported directionally along a short molecular track in a manner reminiscent of the way that biological motor proteins 'walk' along biopolymers in the cell.[8] In 2011 his research group described the smallest molecular knot prepared to date (a 76-atom-loop trefoil knot – three crossing points[9]) and also a 160-atom-loop pentafoil knot (five crossing points).[10] The Leigh group have also reported the synthesis of an 819 knot, the most complex molecular knot made to date,[11] and a molecular endless knot[12] (the smallest Chinese knot). In 2013 the Leigh group reported[13] a small-molecule machine capable of detaching and assembling a series of amino acid building blocks from a track into a peptide of specific sequence, a very primitive version of the task performed by the ribosome. They also invented the first autonomous chemically-fuelled synthetic molecular motor[14] and demonstrated a small-molecule 'robotic arm' able to transport molecular fragments between sites 2 nm apart on a molecular platform, marking the start of so-called 'small-molecule robotics'.[15] In 2017 the Leigh group reported the first molecular robot that can be programmed to build different molecules.[16] The molecular robot could be programmed to construct any one of four different stereoisomers of a molecular product, a significant step towards a 'molecular assembler'. The achievement was hailed as 'science fiction becomes fact'.[17] In 2020 the Leigh group described the 2D weaving of polymer chains,[18] resulting in a molecularly-woven fabric with a thread count of 40-60 million (the finest Egyptian linen has a thread count of ~1500).
Leigh is a former national champion contract bridge player[24] and an accomplished magician (ex-Edinburgh Magic Circle and the Manchester Circle of Magicians), known for blending magic and science in his public lectures.
^Kay, E. R.; Leigh, D. A.; Zerbetto, F. (2007). "Synthetic Molecular Motors and Mechanical Machines". Angewandte Chemie International Edition. 46 (1–2): 72–191. doi:10.1002/anie.200504313. PMID17133632.
^Barran, P. E.; Cole, H. L.; Goldup, S. M.; Leigh, D. A.; McGonigal, P. R.; Symes, M. D.; Wu, J.; Zengerle, M. (2011). "Active-Metal Template Synthesis of a Molecular Trefoil Knot". Angewandte Chemie International Edition. 50 (51): 12280–12284. doi:10.1002/anie.201105012. PMID21919173.
