Realizing Two-Dimensional Supramolecular Arrays of a Spin Molecule via Halogen Bonding

Area of Science:

• Supramolecular Chemistry
• Materials Science
• Surface Science

Background:

• Ordered spin arrays are crucial for advanced molecule-based magnetic devices.
• Current synthetic methods for such arrays are limited and challenging.
• Surface-based molecular self-assembly offers a potential solution.

Purpose of the Study:

• To demonstrate the formation of 2D supramolecular spin arrays on surfaces.
• To explore the role of halogen bonding in directing molecular self-assembly.
• To investigate methods for controlling spin array formation.

Main Methods:

• Synthesis of a bromine-terminated perchlorotriphenylmethyl radical.
• Deposition of the radical onto a Au(111) surface.
• Characterization using low-temperature scanning tunneling microscopy (LT-STM).
• First-principles calculations to understand bonding and structure.

Main Results:

• Successful realization of 2D supramolecular spin arrays via halogen bonding.
• Observation of five distinct spin array structures.
• Identification of three types of halogen bonds influencing array formation.
• Demonstration of control over array structure via molecular coverage and annealing temperature.

Conclusions:

• Supramolecular self-assembly, particularly using halogen bonding, is a viable strategy for engineering 2D molecular spin arrays.
• This approach provides a pathway for designing novel molecule-based magnetic materials.
• The findings open new avenues for controlling magnetic properties at the single-molecule level.