Molecular machines based on 1,3-dipolar cycloadditions

  • Pornpawit Siricharoensang

Student thesis: Master of Science by Research


Since the dawn of the industrial revolution, the desire to build increasingly complex machines has been accompanied by the drive for miniaturization. The most basic denominator for any machine is its parts, and the smallest of which approach the molecular size. The prospect of molecular machines heightens with exploration of a device operating on principles fundamentally different from their macroscopic counterparts. The Leigh group recently achieved a milestone by demonstrating the first single-bond autonomous chemically driven rotary molecular motor, following the principles of biological machinery by continuously fueling its operation against equilibrium. The pyrrole motor has sparked an interest in exploring whether other architectural designs can perform similar tasks. This project aims to investigate the feasibility of designing motors based on common and versatile Click chemistry. Structural variations to the motor are of particular interest, as they may have profound impact on its operation. Such modifications could provide access to new motor motifs, and their activity (directionality, catalytic ability, speed, power) assessed. This study analyzed two structural variants of Leigh's pyrrole motor. The assessment of the click based motors (1-(2-carboxyphenyl)-1H-1,2,3-triazole-5-carboxylic acid) revealed its ability for directional rotation with minimal interference from the heterocyclic rotor. Furthermore, rate enhancement was observed when comparing the triazole stator to when the carboxylic group is electronically isolated from the ring. The next objective aimed to construct a kinetic model to dissect the role of substituents in influencing the motor's performance. Additionally, another variant of the triazole motor by reversing the polarity of the click reaction was also achieved, with potential for creating a library of chiral motors from building blocks derived from natural amino acids. Currently, the functionality of this motor is under investigation, with future plans to introduce a stereogenic center to study intrinsic directional rotation.
Date of Award1 Aug 2024
Original languageEnglish
Awarding Institution
  • The University of Manchester
SupervisorDavid Leigh (Supervisor), Daniel Tetlow (Supervisor) & Michael Greaney (Supervisor)


  • intrinsic directionality
  • click chemistry
  • Molecular machine
  • molecular motor
  • Autonomous machine

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