Gildenast Hans, Garg Felix, Englert Ulli
RWTH Aachen University, Institute of Inorganic Chemistry, Aachen, Germany.
Shanxi University, Key Laboratory of Materials for Energy Conversion and Storage, Institute of Molecular Science, Taiyuan, Shanxi, 030006, People's Republic of China.
Chemistry. 2022 Feb 1;28(7):e202103555. doi: 10.1002/chem.202103555. Epub 2022 Jan 5.
Tris(2-(trimethylsilyl)phenyl)phosphine, P(o-TMSC H ) , was synthesised and characterised in solution and in the solid state. The large steric bulk prevents most reactions of the phosphorus donor and makes the compound air stable both in the solid state as well as in solution. This shielded phosphine can still undergo three reactions, namely protonation, oxidation to the phosphine oxide under harsh conditions and complexation to Au , thus forming a complex with linear coordination. Unexpectedly, complexation was unsuccessful with a range of other metal cations. Neither Pd , Pt , Zn nor Hg reacted and even the remaining coinage metal cations Cu and Ag could not be coordinated. Both the parent molecule as well as the reaction products were structurally characterised by single crystal X-ray diffraction, and the conformational change of geometry required to accommodate the additional atoms was analysed in detail. Apart from chemical oxidation with H O , P(o-TMSC H ) displays reversible electrochemical oxidation with a potential not unlike the one of sterically unencumbered phosphines for which the oxidation is usually not reversible. P(o-TMSC H ) can thus be considered a model compound for the investigation of the electronic properties of sterically unencumbered phosphines.
三（2-（三甲基甲硅烷基）苯基）膦，即P（o-TMSCH），已在溶液和固态中合成并进行了表征。较大的空间位阻阻碍了磷供体的大多数反应，使得该化合物在固态和溶液中都对空气稳定。这种被屏蔽的膦仍能发生三种反应，即质子化、在苛刻条件下氧化为氧化膦以及与Au络合，从而形成具有线性配位的络合物。出乎意料的是，与一系列其他金属阳离子的络合均未成功。Pd、Pt、Zn和Hg均未反应，甚至其余的货币金属阳离子Cu和Ag也无法配位。母体分子以及反应产物均通过单晶X射线衍射进行了结构表征，并详细分析了容纳额外原子所需的几何构象变化。除了用H₂O进行化学氧化外，P（o-TMSCH）还表现出可逆的电化学氧化，其电位与空间位阻较小的膦的电位不同，后者的氧化通常是不可逆的。因此，P（o-TMSCH）可被视为研究空间位阻较小的膦的电子性质的模型化合物。
