A rack-and-pinion device at the molecular scale.

Area of Science:

• Nanotechnology
• Molecular Engineering
• Surface Science

Background:

• Synthetic molecular motors offer potential for atomic-scale precision.
• Current research often involves large molecular ensembles in solution, limiting single-molecule control.
• Adsorbing molecules onto surfaces allows for imaging and manipulation with scanning tunneling microscopy (STM).

Purpose of the Study:

• To demonstrate controlled, single-molecule rotation using a molecular rack-and-pinion mechanism.
• To enable precise manipulation of molecular machines at the atomic scale.
• To overcome limitations of ensemble measurements in molecular machine research.

Main Methods:

• Fabrication of a molecular rack-and-pinion system with a pinion molecule and a molecular island rack.
• Utilizing a scanning tunneling microscope (STM) tip for manipulation at low temperatures.
• Employing a chemical tag on the pinion for monitoring tooth-by-tooth rotation.

Main Results:

• Successfully demonstrated controlled, stepwise rotation of a single pinion molecule using an STM tip.
• The 1.8-nm-diameter pinion molecule functioned as a gear interlocked with the molecular island rack.
• Rotation was monitored precisely, confirming the rack-and-pinion mechanism at the single-molecule level.

Conclusions:

• This work presents the first instance of a controlled, single-molecule rotational device.
• The developed molecular rack-and-pinion system paves the way for precise atomic-scale manipulation.
• This advancement is crucial for the future development and application of single molecular machines.