Supramolecular interactions in a copper(II) 4'-(4-bromophenyl)-2,2':6',2''-terpyridine complex

Area of Science:

• Coordination Chemistry
• Supramolecular Chemistry
• Materials Science

Background:

• Polypyridyl ligands are crucial in coordination chemistry for creating novel metal complexes.
• Copper(II) complexes with polypyridyl ligands exhibit diverse structural and electronic properties.
• Understanding intermolecular interactions is key to designing advanced materials.

Purpose of the Study:

• To synthesize and characterize a new copper(II) complex with a substituted 2,2':6',2''-terpyridine ligand.
• To investigate the coordination geometry and bonding characteristics of the copper center.
• To explore the supramolecular assembly and network formation driven by intermolecular interactions.

Main Methods:

• Synthesis of the title copper(II) complex: [4'-(4-bromophenyl)-2,2':6',2''-terpyridine]chlorido(trifluoromethanesulfonato)copper(II).
• Single-crystal X-ray diffraction to determine the molecular structure and coordination geometry (square-pyramidal).
• Analysis of bond lengths (Cu-N) and intermolecular interactions (Br···F, C-H···Cl, C-H···O).

Main Results:

• The copper(II) center is five-coordinated by the terpyridine ligand, a chloride ion, and a trifluoromethanesulfonate anion.
• Distinct Cu-N bond lengths were observed for peripheral and central pyridine rings (2.032 Å mean and 1.9345 Å, respectively).
• The complex forms dimers via Br···F halogen-halogen interactions and a 3D network through C-H···Cl and C-H···O interactions.

Conclusions:

• The synthesized copper(II) complex displays a unique square-pyramidal geometry.
• The trifluoromethanesulfonate anion plays a role in mediating supramolecular assembly through halogen-halogen interactions.
• The ligand's rigidity facilitates the formation of a robust three-dimensional network via nonclassical interactions, showcasing potential for crystal engineering.