Cerium-carbon dative interactions supported by carbodiphosphorane

Area of Science:

• Organometallic Chemistry
• Rare-Earth Chemistry
• Coordination Chemistry

Background:

• Dative interactions are crucial in organometallic chemistry, influencing complex stability and reactivity.
• Rare-earth metal complexes with carbon-metal bonds are of significant interest due to their unique electronic properties.
• Carbodiphosphorane (CDP) ligands offer novel bonding possibilities with metal centers.

Purpose of the Study:

• To synthesize and characterize novel rare-earth metal complexes with dative interactions involving a carbon(0) ligand.
• To investigate the nature and strength of the metal-carbon dative bonds in these complexes.
• To explore the coordination behavior of carbodiphosphorane (CDP) with trivalent cerium.

Main Methods:

• Synthesis of cerium complexes using cerium bromide (CeBr3) and carbodiphosphorane (CDP).
• Single-crystal X-ray diffraction for structural determination of the synthesized complexes.
• Density functional theory (DFT) calculations to analyze bonding and electronic structure.

Main Results:

• Isolation of complex 2, Br3Ce(CDP)(THF), featuring a single Ce←C dative bond.
• Isolation of complex 3, [BrCe(CDP)2](BPh4)2, with two C→Ce←C dative interactions, an unusual molecular configuration.
• DFT calculations confirmed the presence and strength of σ-dative interactions, with those in complex 3 being stronger than in complex 2.
• Ce-C bond lengths are comparable to those found in cerium(iii)-carbene species.

Conclusions:

• The study successfully demonstrates the formation of dative interactions between rare-earth metals (cerium) and carbon(0) ligands (CDP).
• Complex 3 represents a rare example of a single metal atom forming two dative bonds with the same ligand.
• The findings provide valuable insights into the bonding capabilities of CDP ligands and the electronic structure of organocerium compounds.