Activation of carbon dioxide by divalent tin alkoxides complexes

Area of Science:

• Organometallic Chemistry
• Main Group Chemistry

Background:

• Tin(II) compounds are versatile reagents in synthesis.
• The influence of bulky ligands on tin reactivity is not fully understood.

Purpose of the Study:

• To synthesize and characterize novel tin(II) alkoxides with a bulky beta-diketiminate (BDI) ligand.
• To investigate the nucleophilicity and reactivity of these tin(II) alkoxides, particularly with electrophiles like carbon dioxide.

Main Methods:

• Synthesis of terminal tin(II) alkoxides using the BDI ligand.
• Reactivity studies with electrophiles, including methyl triflate and carbon dioxide.
• Density Functional Theory (DFT) calculations to analyze reaction mechanisms and energetics.

Main Results:

• Successful synthesis of a series of tin(II) alkoxides featuring the BDI ligand.
• Observed reversible reactions with carbon dioxide, with reactivity dependent on the alkoxide ligand (e.g., tert-butoxide vs. isopropyl).
• DFT calculations revealed ground-state energy differences influence CO2 insertion reversibility, while Sn-O bond strengths affect reaction rates.

Conclusions:

• The steric and electronic properties of the alkoxide ligand significantly impact the reactivity and CO2 insertion behavior of tin(II) complexes.
• DFT provides insights into the factors governing the rate and reversibility of CO2 reactions with tin(II) alkoxides.