Molecular Compasses for Modulating Electronic Communication in Pillar[5]quinone.

Area of Science:

• Supramolecular Chemistry
• Molecular Machines
• Electrochemistry

Background:

• Molecular dipole moments can align in response to electric fields, similar to a macroscopic compass.
• Rotaxanes are mechanically interlocked molecules with potential applications in molecular devices.

Purpose of the Study:

• To investigate the behavior of molecular compasses based on [2]rotaxanes with dipole moment pointers.
• To understand how redox control affects dipole-dipole and pole-dipole interactions in these systems.

Main Methods:

• Synthesis and characterization of [2]rotaxane-based molecular compasses.
• Electrochemical studies to observe electron-uptake patterns.
• Density Functional Theory (DFT) calculations to elucidate interaction mechanisms.

Main Results:

• The molecular compasses exhibit a unique 1-1-1-1-1 electron-uptake pattern during initial electron transfers.
• DFT calculations show hydrogen bonding directing dipole orientation upon reduction.
• Electrostatic repulsions from the dipole pointer influence the reduction potentials of the quinoid units.

Conclusions:

• Electronic communication between dipole moment pointers and quinoid units enables [2]rotaxanes to function as molecular compasses.
• Redox changes precisely reorient molecular dipole moments, demonstrating controllable molecular alignment.