Pumping a Ring-Sliding Molecular Motion by a Light-Powered Molecular Motor

Area of Science:

• Supramolecular Chemistry
• Nanotechnology
• Chemical Engineering

Background:

• Designing artificial molecular machines for complex mechanical tasks like motion transmission remains a significant challenge.
• Molecular motors offer potential for controlled mechanical work at the nanoscale.

Purpose of the Study:

• To demonstrate a novel molecular machine capable of coupling rotation and translation.
• To investigate the operational capabilities of a light-driven molecular motor within an interlocked [1]rotaxane system.

Main Methods:

• Fabrication of a molecular machine integrating a second-generation light-driven molecular motor and a bistable [1]rotaxane.
• Characterization using various NMR spectroscopies (1H NMR, 1H-1H COSY, HMQC, HMBC, 2D ROESY).
• Analysis of UV-visible absorption spectra and density functional theory (DFT) calculations.

Main Results:

• The molecular motor successfully rotated within the interlocked [1]rotaxane system.
• Photoinduced cis-to-trans isomerization and thermal helix inversion drove the motor's rotation and the rotaxane's translational motion.
• The motor demonstrated rotation against substantial noncovalent interactions between the dibenzo-24-crown-8 and N-methyltriazolium moieties.

Conclusions:

• This work represents the first successful demonstration of a molecular motor operating against significant noncovalent interactions in a rotaxane system.
• The developed molecular machine showcases advanced capabilities for performing complex mechanical tasks.
• This research paves the way for more sophisticated molecular machines with enhanced functionalities.