Dipolar Molecular Motor Candidates with Planar Chirality

Area of Science:

• Supramolecular Chemistry
• Organometallic Chemistry
• Materials Science

Background:

• Molecular motors are nanoscale machines capable of controlled motion.
• Achieving unidirectional rotation requires asymmetry and external stimuli.
• Integrating chirality and permanent dipoles is crucial for advanced motor design.

Purpose of the Study:

• To synthesize novel molecular motor candidates with planar chirality and permanent dipoles.
• To investigate the impact of ligand design on dipole moments and motor performance.
• To explore the potential for controlled unidirectional rotation under electric fields.

Main Methods:

• Multi-step organic synthesis of functionalized cyclopentadienyl ligands.
• Coordination chemistry to form ruthenium(II) complexes.
• Structural analysis (X-ray crystallography) and Density Functional Theory (DFT) calculations.
• Surface anchoring via thioether moieties.

Main Results:

• Successful synthesis of two molecular motor candidates in seven steps.
• Achieved significant dipole moments (5.60 D and 4.58 D) in the final complexes.
• Overcame synthetic challenges including low yields and side reactions.
• Demonstrated feasibility of integrating chirality and dipoles for motor function.

Conclusions:

• The synthesized ruthenium(II) complexes represent promising molecular motors.
• Permanent dipoles and planar chirality enhance control over molecular motion.
• This work paves the way for STM-controlled molecular machines.