Self-Assembly, Rearrangement, and Disassembly of {Cr₆} Horseshoe Oligomers

Area of Science:

• * Supramolecular Chemistry
• * Materials Science
• * Physical Chemistry

Background:

• * Molecular assemblies are crucial in biological systems, posing a challenge for synthetic chemistry.
• * Designing synthetic mimics requires understanding complex self-assembly processes.
• * Chromium-based {Cr₆}_n horseshoe oligomers represent a model system for studying these phenomena.

Purpose of the Study:

• * To decipher the self-assembly, rearrangement, and disassembly of {Cr₆}_n horseshoe oligomers (n=1-5).
• * To investigate the stability of oligomer units and their behavior on surfaces.
• * To establish a framework for analyzing supramolecular assembly in noncrystalline phases.

Main Methods:

• * Ion mobility mass spectrometry (IM-MS) for analyzing molecular assemblies.
• * Density functional theory (DFT) for computational modeling.
• * Mass-selective electrospray ion beam deposition and low-temperature scanning tunneling microscopy (STM) for surface studies.

Main Results:

• * Activated tandem IM-MS detailed oligomer disassembly, confirming the stability of the dimer unit.
• * Deposited n=2 and n=3 oligomers rearranged into dimers of dimers.
• * Higher coverages led to the formation of an unexpected hexagonal-like network.

Conclusions:

• * The study provides a comprehensive analysis of {Cr₆}_n horseshoe oligomer assembly and disassembly.
• * Experimental and computational data offer a framework for understanding supramolecular processes in noncrystalline phases.
• * Findings can inform future design strategies for synthetic molecular assemblies.