Biphenolate phosphine complexes of tin(IV)

The preparation and structural characterization of tin(IV) complexes supported by (2,2′-phenylphosphino)bis(4,6-di-tert-butylphenolate) ([OPO]^2-) are described. The reaction of in-situ prepared Li ₂[OPO] with SnCl₄ in THF at -35°C produced [OPO]SnCl₂(THF) as a THF adduct. Addition of SnCl₄ to a THF solution of H₂[OPO] in the presence of 2 equiv of NEt₃ at room temperature led to the formation of the "ate" complex {[OPO]SnCl₃}(HNEt₃). The metathetical reactions of Li ₂[OPO] with R₂SnCl₂ (R = Me, n-Bu) in THF at -35°C generated the corresponding five-coordinate dialkyl complexes [OPO]SnR₂. In addition to the multinuclear NMR spectroscopic data for all new compounds, X-ray structures of [OPO]SnCl₂(THF), [OPO]SnMe₂, and [OPO]Sn(n-Bu)₂ are presented.