Synthesis, purification, and characterization of phosphine oxides and their hydrogen peroxide adducts
作者:Casie R. Hilliard、Nattamai Bhuvanesh、John A. Gladysz、Janet Blümel
DOI:10.1039/c1dt11863c
日期:——
Reactions of the tertiary phosphines R3P (R = Me, Bu, Oct, Cy, Ph) with 35% aqueous H2O2 gives the corresponding oxides as the H2O2 adducts R3PO·(H2O2)x (x = 0.5–1.0). Air oxidation leads to a mixture of products due to the insertion of oxygen into one or more P–C bonds. 31P NMR spectroscopy in solution and in the solid state, as well as IR spectroscopy reveal distinct features of the phosphine oxides as compared to their H2O2 adducts. The single crystal X-ray analyses of Bu3PO and [Cy3PO·(H2O2)]2 show a PO stacking motif for the phosphine oxide and a cyclic structure, in which the six oxygen atoms exhibit a chair conformation for the dimeric H2O2 adduct. Different methods for the decomposition of the bound H2O2 and the removal of the ensuing strongly adsorbed H2O are evaluated. Treating R3PO·(H2O2)x with molecular sieves destroys the bound H2O2 safely under mild conditions (room temperature, toluene) within one hour and quantitatively removes the adsorbed H2O from the hygroscopic phosphine oxides within four hours. At 60 °C the entire decomposition/drying process is complete within one hour.
三苯膦R3P(R = Me,Bu,Oct,Cy,Ph)与35% H2O2水溶液反应生成相应的氧化物,作为H2O2加合物R3PO·(H2O2)x(x = 0.5–1.0)。空气氧化导致产生产品混合物,这是由于氧插入一个或多个P-C键中所致。31P NMR光谱在溶液中和固体状态下,以及IR光谱显示与它们的H2O2加合物相比,膦氧化物具有不同的特征。单晶X射线分析显示Bu3PO和[Cy3PO·(H2O2)]2中磷氧化物呈PO堆叠基序,其中六个氧原子在二聚H2O2加合物中呈椅子构象。评估了解离结合的H2O2和除去随后强烈吸附的H2O的不同方法。在温和条件下(室温,甲苯)用分子筛处理R3PO·(H2O2)x,在一小时内安全地破坏结合的H2O2,并在四小时内定量地从吸湿性磷氧化物中除去吸附的H2O。在60°C下,整个分解/干燥过程在一小时内完成。