Biphenolate Phosphine Complexes of Tin(IV)

The preparation and structural characterization of tin(IV) complexes supported by (2,2‘-phenylphosphino)bis(4,6-di-<i>tert</i>-butylphenolate) ([OPO]<sup>2-</sup>) are described. The reaction of in-situ prepared Li<sub>2</sub>[OPO] with SnCl<sub>4</sub> in THF at −35 °C produced [OPO]SnCl<sub>2</sub>(THF) as a THF adduct. Addition of SnCl<sub>4</sub> to a THF solution of H<sub>2</sub>[OPO] in the presence of 2 equiv of NEt<sub>3</sub> at room temperature led to the formation of the “ate” complex {[OPO]SnCl<sub>3</sub>}(HNEt<sub>3</sub>). The metathetical reactions of Li<sub>2</sub>[OPO] with R<sub>2</sub>SnCl<sub>2</sub> (R = Me, <i>n-</i>Bu) in THF at −35 °C generated the corresponding five-coordinate dialkyl complexes [OPO]SnR<sub>2</sub>. In addition to the multinuclear NMR spectroscopic data for all new compounds, X-ray structures of [OPO]SnCl<sub>2</sub>(THF), [OPO]SnMe<sub>2</sub>, and [OPO]Sn(<i>n-</i>Bu)<sub>2</sub> are presented.