Binding Interactions in Copper, Silver and Gold π-Complexes

Area of Science:

• Organometallic Chemistry
• Coordination Chemistry
• Spectroscopy

Background:

• Copper(I), silver(I), and gold(I) metals form complexes with π-ligands.
• These interactions involve both σ-donation and π-back bonding.
• Ancillary ligands with varying electronic properties are used to study these bonds.

Purpose of the Study:

• To investigate the σ-bonding and π-back bonding interactions in copper(I), silver(I), and gold(I) complexes with π-ligands.
• To determine how ancillary ligand substituents influence metal-ligand binding.
• To compare binding affinities across different metals and ligand types (alkenes vs. alkynes).

Main Methods:

• Synthesis of copper(I), silver(I), and gold(I) complexes with bidentate ancillary ligands.
• X-ray crystallography to determine molecular structures.
• Nuclear Magnetic Resonance (NMR) and Infrared (IR) spectroscopy for electronic analysis.
• Gas-phase experiments to measure binding energies.

Main Results:

• Binding energies increase in the order Silver < Copper < Gold.
• Binding energies are slightly higher for alkynes compared to alkenes.
• π-back bonding significantly influences binding in copper and gold complexes, modulated by ancillary ligand substituents.

Conclusions:

• The electronic properties of ancillary ligands critically affect metal-ligand interactions in these complexes.
• π-back bonding is a dominant factor in the stability of copper and gold π-complexes.
• The study provides insights into the fundamental bonding principles governing coinage metal π-complexes.