Observing invisible machines with invisible light: The mechanics of molecular machines

Over the past few decades, chemists have designed and constructed a large variety of artificial molecular machines. Understanding of the fundamental principles behind motion at the molecular scale is key to the development of such devices. Motion at the molecular level is very different from that experienced in the macroscopic world: molecular devices have to operate in a constant thermal noise and must therefore make use of the specificity of chemical reactions or external stimuli to produce work.
In this thesis we, have investigated how non-covalent interactions between the components of molecular machines govern their operation. The principal technique we use to investigate the mechanics of molecular machines is time-resolved vibrational spectroscopy. In this thesis, we observed the directional motion of invisible machines with invisible light. We learned that the operation of molecular devices is intrinsically random due the environment in which they operate. We were able to accelerate the operation of hydrogen-bonding molecular machines with water, and discovered that this type of "lubrication" could also occur in biological systems. We proved that the rupture of the non-covalent interactions between the components of the molecular machines investigated here is the step which determines the speed at which they operate and that quantum mechanical effects can be used to influence the operation of molecular machines. Finally, we followed and characterized the conformational changes of the components of a molecular shuttle during its operation cycle in a time-resolved manner.