New cruciform structures: toward coordination induced single molecule switches.

Area of Science:

• Molecular electronics
• Supramolecular chemistry
• Surface science

Background:

• Investigating single-molecule switching mechanisms is crucial for molecular electronics.
• Understanding molecule-electrode interface interactions is key to device functionality.
• Designing molecules with specific anchoring and coordinating groups is essential for controlled assembly.

Purpose of the Study:

• To synthesize novel cruciform molecules for investigating a new single-molecule switching mechanism.
• To explore the interplay between molecular structure and electrode surface interactions.
• To functionalize molecules with sulfur anchors and pyridine units for controlled electronic coupling.

Main Methods:

• Synthesis of cruciform molecules 1-4 using Wittig and Sonogashashira-Hagihara coupling reactions.
• Functionalization with acetyl-protected sulfur anchor groups and terminal pyridine units.
• Transport investigations using a mechanical controllable break junction in a liquid environment.

Main Results:

• Successful synthesis of cruciform molecules 1-4.
• Demonstration of single-molecule trapping between gold electrodes via sulfur anchors in molecular cruciforms 2 and 4.
• Preliminary evidence for molecule-electrode interactions.

Conclusions:

• The synthesized cruciform molecules are suitable for single-molecule electronic studies.
• The sulfur anchors facilitate stable molecule-electrode contacts.
• Further investigation is needed to elucidate the electrochemical potential-dependent switching mechanism involving pyridine coordination.