Structures of [CoO(CO2)n]- and [NiO(CO2)n]- clusters studied by infrared spectroscopy

Area of Science:

• Inorganic Chemistry
• Computational Chemistry
• Spectroscopy

Background:

• Metal-ligand interactions are crucial in catalysis and materials science.
• Understanding the structure of small metal-containing clusters provides fundamental insights into chemical bonding.

Purpose of the Study:

• To investigate the structural properties of cobalt-carbon dioxide ([CoO(CO2)n](-)) and nickel-carbon dioxide ([NiO(CO2)n](-)) clusters.
• To compare the isomeric structures of these anionic metal-CO2 clusters.

Main Methods:

• Infrared spectroscopy was used to probe the vibrational modes of the clusters.
• Density functional theory (DFT) calculations were employed to interpret the experimental spectra and determine stable isomeric structures.

Main Results:

• Both [CoO(CO2)n](-) and [NiO(CO2)n](-) clusters exhibit similar core isomeric structures.
• The dominant isomers feature an η(2) coordinated CO2 ligand and a CO3 moiety.
• The CO3 moiety can bind to the metal center via monodentate (η(1)) or bidentate (η(2)) connectivity.
• Minor isomers include structures with a C2O4 moiety or a CO3 unit.

Conclusions:

• Cobalt and nickel exhibit analogous coordination behavior with CO2 and carbonate ligands in these anionic clusters.
• The findings provide a detailed understanding of the structural landscape and bonding in M-CO2 systems.