Biphenolate phosphine complexes of tin(IV).

Area of Science:

• Organometallic Chemistry
• Coordination Chemistry
• Main Group Chemistry

Background:

• Tin(IV) complexes are crucial in various catalytic and material science applications.
• Developing novel ligands is key to tuning the reactivity and properties of metal complexes.
• The (2,2 ahydro-phenylphosphino)bis(4,6-di-tert-butylphenolate) ([OPO]2-) ligand offers unique steric and electronic properties for metal coordination.

Purpose of the Study:

• To synthesize and structurally characterize new tin(IV) complexes supported by the [OPO]2- ligand.
• To explore the reactivity of tin(IV) precursors with the [OPO]2- ligand under various conditions.
• To investigate the coordination behavior and structural diversity of the resulting tin(IV) complexes.

Main Methods:

• Synthesis of tin(IV) complexes via reactions of tin tetrachloride (SnCl4) and dialkyltin dichlorides (R2SnCl2) with the [OPO]2- ligand precursor.
• Characterization using multinuclear NMR spectroscopy (e.g., 1H, 13C, 31P, 119Sn NMR).
• Single-crystal X-ray diffraction analysis for structural elucidation of key compounds.

Main Results:

• Successful synthesis of [OPO]SnCl2(THF), a THF adduct, from Li2[OPO] and SnCl4.
• Formation of the "ate" complex {[OPO]SnCl3}(HNEt3) via reaction of H2[OPO] with SnCl4 and triethylamine.
• Preparation of five-coordinate dialkyltin complexes, [OPO]SnR2 (R=Me, n-Bu), through metathetical reactions.
• X-ray structures confirmed the coordination environment and geometry of [OPO]SnCl2(THF), [OPO]SnMe2, and [OPO]Sn(n-Bu)2.

Conclusions:

• The [OPO]2- ligand effectively supports the formation of diverse tin(IV) complexes.
• The synthetic routes provide access to various coordination geometries around the tin center.
• The structural data offer insights into the bonding and reactivity of these novel organotin compounds.