Insertion of a Nontrigonal Phosphorus Ligand into a Transition Metal-Hydride: Direct Access to a Metallohydrophosphorane

The
synthesis and reactivity of an NPN-chelating ligand containing
a nontrigonal phosphorous triamide center (L1 = P­(N­(o-N­(2-pyridyl)­C6H4)2) is
reported. Metalation of L1 with RuCl2(PPh3)3 gives RuCl2(PPh3)­(L1) (2). By contrast, metalation of L1 with RuHCl­(CO)­(PPh3)3 yields RuCl­(CO)­(PPh3)­(L1H) (3), a chelated
10-P-5 ruthenahydridophosphorane, via net insertion into the Ru–H
bond. Hydride abstraction from 3 with Ph3CPF6 gives [RuCl­(CO)­(PPh3)­(L1)]­PF6 (4); reaction of 4 with NaBH4 returns 3.

本文报道了一种含非三角构型磷三酰胺中心的NPN螯合配体（NPN-chelating ligand）的合成与反应性，该配体记为L1 = P(N-(邻-N-(2-吡啶基)苯基)₂)。将L1与三(三苯基膦)二氯化钌(RuCl2(PPh3)3)进行金属化反应，得到二氯化(三苯基膦)(L1)合钌(2)。与之相对，将L1与三(三苯基膦)羰基氯化氢合钌(RuHCl(CO)(PPh3)3)进行金属化反应时，经Ru-H键的净插入过程，生成了螯合型10-P-5钌杂氢膦烷配合物——氯化(羰基)(三苯基膦)(L1H)合钌(3)。采用三苯基六氟磷酸碳鎓(Ph3CPF6)对配合物3进行氢负离子攫取，得到[RuCl(CO)(PPh3)(L1)]PF6（即配合物4）；而配合物4与硼氢化钠(NaBH4)反应可重新得到配合物3。