Toward Fast and Efficient Visible-Light-Driven Molecular Motors: A Minimal Design

Area of Science:

• Molecular Engineering
• Photochemistry
• Supramolecular Chemistry

Background:

• Developing light-driven rotary molecular motors for biological and medical applications requires shifting from UV to visible light.
• Current visible-light motors often suffer from low quantum yields or require subsequent thermal steps, limiting their utility.

Purpose of the Study:

• To present and evaluate a minimal design for visible-light-driven molecular motors that overcomes the limitations of existing systems.
• To achieve efficient rotary motion using visible light without compromising quantum yield or requiring thermal assistance.

Main Methods:

• Utilized state-of-the-art quantum chemical calculations to analyze the motor's design and photochemical properties.
• Employed molecular dynamics simulations to assess the rotary motion and excited-state dynamics.

Main Results:

• The proposed minimal design, featuring dihydropyridinium and cyclohexenylidene motifs, enables a full 360° rotation.
• The motor operates via fast photoisomerizations with excited-state lifetimes of approximately 170-250 fs.
• The process is powered by photons with energies well below 3 eV, indicating efficient visible light utilization.

Conclusions:

• The presented molecular motor design effectively utilizes visible light for efficient rotary motion.
• This design offers a promising alternative to UV-driven motors and overcomes drawbacks of existing visible-light systems.
• The findings pave the way for advanced applications in biology and medicine.