CuBr₂ complexes with 3,5-disubstituted pyridine ligands

Area of Science:

• Coordination Chemistry
• Materials Science
• Crystallography

Background:

• Copper(II) bromide serves as a versatile precursor for synthesizing coordination polymers.
• Substituted pyridines, such as 3,5-dichloropyridine and 3,5-dimethylpyridine, can act as ligands in metal-organic frameworks.
• Understanding the self-assembly of metal-ligand complexes is crucial for designing novel materials.

Purpose of the Study:

• To synthesize and characterize novel coordination polymers of copper(II) with 3,5-dichloropyridine and 3,5-dimethylpyridine.
• To investigate the structural features, including bridging ligands and intermolecular interactions, of the resulting coordination polymers.
• To explore the influence of pyridine substituents on the crystal packing and dimensionality of the copper(II) coordination networks.

Main Methods:

• Reaction of copper(II) bromide with 3,5-dichloropyridine and 3,5-dimethylpyridine.
• Isolation and single-crystal X-ray diffraction analysis of the resulting coordination polymers.
• Characterization of the coordination polymer structures, including bond distances and intermolecular interactions.

Main Results:

• Two coordination polymers, [CuBr2(3,5-Cl2py)2] (1) and [CuBr2(3,5-Me2py)2] (2), were successfully synthesized.
• Both compounds exhibit bibromide-bridged copper(II) chains with an average Cu⋯Cu distance of 3.93(9) Å.
• Polymer 1 displays linking via non-classical hydrogen bonds and halogen bonds, while polymer 2 shows only non-classical hydrogen bonds.

Conclusions:

• The reaction of copper(II) bromide with substituted pyridines yields one-dimensional coordination polymers.
• The nature of the pyridine substituent influences the intermolecular interactions and crystal packing in the solid state.
• Bibromide bridging is a common motif in these copper(II) coordination polymer systems.