Unsupported Bonds between Copper(I) and Heavier Pnictogens

Area of Science:

• Organometallic Chemistry
• Inorganic Chemistry
• Computational Chemistry

Background:

• Stabilization of copper(I) complexes with heavy pnictogen donors is challenging.
• Understanding trends in group 15 elements is crucial for designing new complexes.
• Fluorinated ligands offer unique electronic properties for stabilizing reactive metal centers.

Purpose of the Study:

• To synthesize and characterize copper(I) complexes with heavy pnictogen donors (Sb, Bi).
• To investigate the role of fluorinated poly(pyrazolyl)borate ligands in stabilizing these complexes.
• To analyze trends across group 15 elements in copper complexes and understand bonding characteristics.

Main Methods:

• Synthesis of copper(I) complexes utilizing fluorinated poly(pyrazolyl)borate ligands.
• Characterization of complexes via X-ray crystallography and spectroscopic methods.
• Density Functional Theory (DFT) calculations to analyze bonding, stabilization energies, and electronic properties.

Main Results:

• Successful stabilization of copper(I) complexes with triphenylarsine (AsPh₃), triphenylstibine (SbPh₃), and triphenylbismuthine (BiPh₃).
• Isolation of a novel copper-bismuthine complex with a direct, unsupported Cu-Bi bond.
• DFT calculations reveal decreasing stabilization energy from P to Bi, highlighting relativistic effects and electrostatic dominance in Cu-E bonding.

Conclusions:

• Fluorinated poly(pyrazolyl)borate ligands effectively stabilize copper(I) complexes with heavy pnictogen donors.
• Relativistic effects significantly influence the bonding and Lewis basicity of heavier pnictogens.
• The study provides fundamental insights into the coordination chemistry of heavy pnictogens with copper and the impact of ligand design.