Formation of P–C Bond through Reductive Coupling between Bridging Phosphido and Benzoquinolinate Groups. Isolation of Complexes of the Pt(II)/Pt(IV)/Pt(II) Sequence

The rational synthesis of dinuclear asymmetric phosphanido
derivatives
of palladium and platinum­(II), [NBu4]­[(RF)2M­(μ-PPh2)2M′(κ2,N,C-C13H8N)] (RF = C6F5; M = M′
= Pt, 1; M = Pt, M′ = Pd, 2; M =
Pd, M′ = Pt, 3; M = M′ = Pd, 4), is described. Addition of I2 to 1–4 gives complexes [(RF)2MII(μ-PPh2)­(μ-I)­PdII{PPh2(C13H8N)}] (M = M′ = Pt, 6; M = Pt, M′ = Pd, 7; M = M′ = Pd, 8; M = Pd, M′ = Pt 10) which contain the
aminophosphane PPh2(C13H8N) ligand
formed through a Ph2P/C∧N reductive coupling
on the mixed valence M­(II)–M′(IV) [NBu4]­[(RF)2MII(μ-PPh2)2M′IV(κ2,N,C- C13H8N)­I2] complexes,
which were identified for MII = Pd, M′IV = Pt (9), and isolated for MII = Pt, M′IV = Pt (5). Complex 5 showed an
unusual dynamic behavior consisting in the exchange of two phenyl
groups bonded to different P atoms, as well as a “through space”
spin–spin coupling between ortho-F atoms of
the pentafluorophenyl rings.

本文报道了钯与铂(II)双核不对称膦基衍生物的可控合成，其通式为[NBu4][(RF)2M(μ-二苯基膦基)2M′(κ2,N,C-配位的C13H8N)]，其中RF为五氟苯基(C6F5)，具体化合物包括：M=M′=Pt（化合物1）、M=Pt、M′=Pd（化合物2）、M=Pd、M′=Pt（化合物3）、M=M′=Pd（化合物4）。向化合物1~4中加入碘单质(I2)，可得到通式为[(RF)2MII(μ-二苯基膦基)(μ-碘基)PdII{PPh2(C13H8N)}]的配合物，对应化合物分别为：M=M′=Pt（化合物6）、M=Pt、M′=Pd（化合物7）、M=M′=Pd（化合物8）、M=Pd、M′=Pt（化合物10）。该类配合物中包含的氨基膦PPh2(C13H8N)配体，是通过混合价态M(II)-M′(IV)的中间体配合物[NBu4][(RF)2MII(μ-二苯基膦基)2M′IV(κ2,N,C-C13H8N)I2]发生Ph2P/C∧N还原偶联反应生成的。其中，MII=Pd、M′IV=Pt的中间体（化合物9）仅被表征鉴定，而MII=Pt、M′IV=Pt的中间体（化合物5）则被分离得到。化合物5表现出非常规的动态行为，包括键合于不同磷原子上的两个苯基的交换过程，以及五氟苯基环邻位氟原子之间的空间穿越自旋-自旋耦合作用。