Directional Bias in Molecular Photogearing Evidenced by LED-Coupled Chiral Cryo-HPLC.

Molecular gearing systems are technomimetic nanoscale analogues to complex geared machinery in the macroscopic world. They are defined as systems incorporating intermeshed movable parts which perform correlated rotational motions by mechanical engagement. Only recently, new methods to actively drive molecular gearing motions instead of relying on passive thermal activation have been developed.

Photogearing as a concept for translation of precise motions at the nanoscale.

One of the major challenges for harnessing the true potential of functional nano-machinery is integrating and transmitting motion with great precision. Molecular gearing systems enable the integration of multiple motions in a correlated fashion to translate motions from one locality to another and to change their speed and direction. However, currently no powerful methods exist to implement active driving of gearing motions at the molecular scale.

Sulfoxide hemithioindigo tweezers - visible light addressable capture and release.

Introducing responsive elements into supramolecular recognition systems offers great advantages for the control of intermolecular interactions and represents an important stepping stone towards multi-purpose and reprogrammable synthetic systems. Of particular interest is implementation of light-responsiveness because of the unique ease and precision of this signal. Here we present visible light responsive hemithioindigo-based molecular tweezers that bear a highly polar sulfoxide function as an additional recognition unit inside their binding site.