Self-assembled trinuclear arsenic and antimony macrobicycles

Area of Science:

• Inorganic Chemistry
• Supramolecular Chemistry
• Materials Science

Background:

• Pnictogen chemistry offers unique bonding and structural possibilities.
• Macrobicyclic structures provide platforms for complex molecular architectures.
• Self-assembly is a powerful strategy for constructing intricate molecules.

Purpose of the Study:

• To synthesize and characterize novel trinuclear pnictogen (As, Sb) macrobicycles.
• To investigate the solution behavior and isomerism of these macrobicyclic complexes.
• To explore the influence of solvent on the self-assembly process and product distribution.

Main Methods:

• Self-assembly of pnictogen trichlorides with a benzenetrimethanethiol ligand.
• Nuclear Magnetic Resonance (1H-NMR) spectroscopy for structural elucidation and dynamic studies.
• X-ray crystallography for definitive structural confirmation.
• Computational studies (MP2/LANL2DZ optimizations) for theoretical analysis.

Main Results:

• Successful synthesis of six trinuclear Pn3L2 macrobicycles (Pn = As, Sb).
• Observation of dynamic self-assembly in solution, leading to structural isomers.
• As3L2 complexes yielded a 2:1 mixture of symmetric and asymmetric isomers.
• Sb3L2 complexes exclusively formed the symmetric isomer in solution.
• Solvent effects were identified as crucial for isomer distribution and product formation.

Conclusions:

• The study demonstrates a versatile self-assembly route to novel pnictogen macrobicycles.
• Distinct solution behaviors and isomer distributions were observed for arsenic and antimony complexes.
• Solvent plays a critical role in controlling conformational isomerism and product outcomes in these systems.