Metalorganics and Inorganic Materials, Department of Chemistry, Technische Universität Berlin, Straße des 17. Juni 135, Sekr. C2, 10623 Berlin, Germany.
J Am Chem Soc. 2013 Aug 14;135(32):11795-8. doi: 10.1021/ja4072699. Epub 2013 Aug 1.
The simplest parent phosphinidene, :PH (1), has been observed only in the gas phase or low temperature matrices and has escaped rigorous characterization because of its high reactivity. Its liberation and transfer to an unsaturated organic molecule in solution has now been accomplished by taking advantage of the facile homolytic bond cleavage of the fragile Si═P bond of the first zwitterionic phosphasilene LSi=PH (8) (L = CH[(C═CH2)CMe(NAr)2]; Ar = 2,6-(i)Pr2C6H3). The latter bears two highly localized lone pairs on the phosphorus atom due to the LSi═PH ↔ LSi(+)-PH(-) resonance structures. Strikingly, the dissociation of 8 in hydrocarbon solutions occurs even at room temperature, affording the N-heterocyclic silylene LSi: (9) and 1, which leads to oligomeric [PH]n clusters in the absence of a trapping agent. However, in the presence of an N-heterocyclic carbene as an unsaturated organic substrate, the fragile phosphasilene 8 acts as a :PH transfer reagent, resulting in the formation of silylene 9 and phosphaalkene 11 bearing a terminal PH moiety.
最简单的母体膦烯，:PH（1），仅在气相或低温基质中观察到，由于其高反应性，尚未进行严格的表征。现在，通过利用第一个两性离子磷硅烯 LSi=PH（8）（L = CH[(C=CH2)CMe(NAr)2]；Ar = 2,6-(i)Pr2C6H3）中脆弱的 Si═P 键的易均裂键断裂，实现了其在溶液中向不饱和有机分子的释放和转移。后者由于 LSi═PH ↔ LSi(+)-PH(-)共振结构，在磷原子上带有两个高度局域的孤对电子。引人注目的是，即使在室温下，8 在烃类溶液中的解离也会发生，从而在没有捕获剂的情况下形成聚合的[PH]n 簇。然而，在作为不饱和有机底物的 N-杂环卡宾存在下，脆弱的磷硅烯 8 充当:PH 转移试剂，导致带有末端 PH 部分的硅烯 9 和磷杂戊二烯 11 的形成。
