作者:Keith Izod、John C. Stewart、William Clegg、Ross W. Harrington
DOI:10.1039/b715145d
日期:——
The reaction between (Me3Si)2CH}PCl2 and one equivalent of [C10H6-8-NMe2]Li, followed by in situreduction with LiAlH4, gives the secondary phosphane (Me3Si)2CH}(C10H6-8-NMe2)PH (1) in good yield as a colourless crystalline solid. Metalation of 1 with BunLi in diethyl ether gives the lithium phosphanide [[(Me3Si)2CH}(C10H6-8-NMe2)P]Li}2(OEt2)] (2), which undergoes metathesis with either NaOBut or KOBut to give the heavier alkali metal derivatives [[(Me3Si)2CH}(C10H6-8-NMe2)P]Na(tmeda)] (3) and [[(Me3Si)2CH}(C10H6-8-NMe2)P]K(pmdeta)] (4), after recrystallisation in the presence of the corresponding amine co-ligand [tmeda = N,N,N′,N′-tetramethylethylenediamine, pmdeta = N,N,N′,N″,N″-pentamethyldiethylenetriamine]. Compounds 2–4 have been characterised by 1H, 13C1H} and 31P1H} NMR spectroscopy, elemental analyses and X-ray crystallography. Dinuclear 2 crystallises with the phosphanide ligands arranged in a head-to-head fashion and is subject to dynamic exchange in toluene solution; in contrast, compounds 3 and 4 crystallise as discrete monomers which exhibit no dynamic behaviour in solution. DFT calculations on the model compound [[(Me)(C10H6-8-NMe2)P]Li}2(OMe2)] (2a) indicate that the most stable head-to-head form is favoured by 15.0 kcal mol–1 over the corresponding head-to-tail form.
(Me3Si)2CH}PCl2 与 1 个等量的 [C10H6-8-NMe2]Li 反应,然后与 LiAlH4 发生原位反应,得到二级膦烷(Me3Si)2CH}(C10H6-8-NMe2)PH (1),它是一种无色结晶固体,收率很高。在二乙醚中用 BunLi 对 1 进行金属化,可得到锂膦[[(Me3Si)2CH}(C10H6-8-NMe2)P]Li}2(OEt2)](2)、与 NaOBut 或 KOBut 发生偏析反应,生成较重的碱金属衍生物[[(Me3Si)2CH}(C10H6-8-NMe2)P]Na(tmeda)] (3) 和[[(Me3Si)2CH}(C10H6-8-NMe2)P]K(pmdeta)] (4)、tmeda = N,N,N′,N′-四甲基乙二胺,pmdeta = N,N,N′,N″,N″-五甲基二乙烯三胺]。化合物 2-4 已通过 1H、13C1H} 和 31P1H} 核磁共振光谱、元素分析和化学分析进行了表征。核磁共振光谱、元素分析和 X 射线晶体学对 2-4 号化合物进行了表征。双核 2 的结晶中,膦配体以头对头的方式排列,并在甲苯溶液中发生动态交换;相比之下,化合物 3 和 4 以离散单体的形式结晶,在溶液中不表现出动态行为。对模型化合物[[(Me)(C10H6-8-NMe2)P]Li}2(OMe2)] (2a)的 DFT 计算表明,最稳定的头对头形式比相应的头对尾形式有利 15.0 kcal mol-1。