Antimony vs. bismuth: structural differences in Cat{[MCl₅](I₂)} halogen bond-linked supramolecular complexes.

Area of Science:

• Inorganic Chemistry
• Crystal Engineering
• Supramolecular Chemistry

Background:

• Halogen bonding is a crucial non-covalent interaction in crystal engineering.
• The exploration of hybrid organic-inorganic materials with unique structural motifs is ongoing.
• Antimony(III) and Bismuth(III) halides offer versatile coordination chemistry.

Purpose of the Study:

• To synthesize and characterize novel hybrid chloroantimonates(III) and chlorobismuthates(III).
• To investigate the role and features of halogen bonding in these new compounds.
• To explore the structural diversity arising from similar supramolecular anionic units.

Main Methods:

• Hydrothermal synthesis involving metal oxides (Sb2O3/Bi2O3), iodine (I2), and bis(pyridines) in HCl.
• Single-crystal X-ray diffraction for structural determination.
• Computational methods (e.g., theoretical analysis) to examine halogen bonding.

Main Results:

• Four new hybrid compounds with the general formula (H2L){[MCl5](I2)} (L=bpe, bpp; M=Sb(III), Bi(III)) were successfully synthesized.
• Despite sharing the same supramolecular anionic formula {[MCl5](I2)}, the compounds exhibited three distinct structural types.
• Analysis confirmed the presence and significance of halogen bond-linked I2 units within the crystal structures.

Conclusions:

• The synthesis yielded novel hybrid metal halides incorporating halogen-bonded iodine.
• Structural diversity was observed, highlighting the nuanced packing arrangements in these systems.
• Theoretical examination provided insights into the nature of halogen bonding in the studied compounds.