Structure correlation study of four-coordinate copper(I) and (II) complexes

Area of Science:

• Inorganic Chemistry
• Structural Chemistry
• Computational Chemistry

Background:

• Understanding the geometric preferences of metal complexes is crucial in coordination chemistry.
• The Cambridge Structural Database (CSD) provides a vast repository for analyzing structural trends.

Purpose of the Study:

• To systematically analyze and compare the geometries of four-coordinate copper(I) and copper(II) complexes.
• To rationalize observed stereochemistries based on electronic and steric factors.

Main Methods:

• Utilized symmetry-deformation coordinates and principal component analysis.
• Systematic analysis of four-coordinate copper complexes within the CSD.
• Rationalization of geometries using d-electron configurations, interligand repulsion, and pi-bonding effects.

Main Results:

• The majority of four-coordinate copper(I) complexes adopt tetrahedral geometries.
• Deviations in copper(I) geometries are linked to chelating ligands or polymeric structures.
• Four-coordinate copper(II) complexes predominantly exhibit square planar geometries, especially bis(chelate) complexes.
• Distortions in copper(II) geometries towards tetrahedral are attributed to steric interactions of bulky substituents.

Conclusions:

• Geometric preferences of four-coordinate copper complexes are influenced by electronic and steric factors.
• Chelating ligands and structural aggregation play significant roles in copper(I) geometry.
• Pi-bonding interactions are key in determining the square planar preference of copper(II) complexes.