Light-Gated Rotation in a Molecular Motor Functionalized with a Dithienylethene Switch

Area of Science:

• Supramolecular Chemistry
• Organic Chemistry
• Materials Science

Background:

• Molecular motors are nanoscale machines that perform mechanical work using external energy sources.
• Controlling molecular motor function with external stimuli is crucial for developing advanced molecular devices.
• Multiphotochromic systems offer tunable properties through light-induced transformations.

Purpose of the Study:

• To create a hybrid system combining a molecular rotary motor with a photoswitchable unit.
• To achieve light-gated control over the operation of a molecular motor.
• To investigate the influence of the photoswitch on the motor's properties, such as its excitation wavelength.

Main Methods:

• Synthesis of a hybrid system integrating an overcrowded alkene-based molecular rotary motor and a dithienylethene photoswitch.
• Utilizing distinct irradiation wavelengths to operate the motor and trigger the photoswitch.
• Characterization using detailed 1H-NMR and UV/Vis spectroscopy to monitor structural changes and functional inhibition.

Main Results:

• Demonstrated successful integration of a molecular motor and a dithienylethene photoswitch.
• Showcased light-gated inhibition of the molecular motor's rotary motion via photoswitch ring-closing.
• Observed a red-shift in the molecular motor's excitation wavelength into the visible region upon photoswitch attachment.

Conclusions:

• Successfully developed the first light-gated molecular motor system.
• The dithienylethene photoswitch effectively modulates the motor's function through light control.
• The hybrid system exhibits tunable optical properties, expanding the potential applications of molecular motors.