Controlling molecular machines via optimally oriented external electric fields

Area of Science:

• Physical Chemistry
• Materials Science
• Nanotechnology

Background:

• Brownian motion rectification is key for molecular machine operation.
• Electric fields (E-fields) offer a promising method for controlling molecular motion.
• Existing control methods often require high energy inputs or specific molecular designs.

Purpose of the Study:

• To demonstrate E-field-driven control of molecular motion in distinct molecular machines.
• To identify optimal E-field orientations for efficient molecular motion control.
• To computationally validate a new polarizable molecular electric dipole model for predicting E-field effects.

Main Methods:

• Computational modeling using a polarizable molecular electric dipole model.
• Simulation of E-field effects on two molecular machine models: a fluorene-based alkene and an achiral rotor.
• Analysis of potential energy surfaces to identify E-field-induced changes in transition states and energy minima.

Main Results:

• E-fields can induce bidirectional isomerization in the ground state, bypassing high-energy photochemical pathways.
• Optimal E-field orientations transform activated steps into barrierless processes, enabling directional control.
• Logical control over molecular rotation, including 'STOP' and 'GO' states, is achieved without molecular chirality.
• Predicted field strengths are compatible with current scanning tunneling microscope technology.

Conclusions:

• E-fields provide a generalizable and non-invasive strategy for controlling molecular machines.
• This approach enables precise manipulation of molecular motion for advanced synthetic and biological applications.
• The findings pave the way for designing next-generation E-field-controlled molecular devices.