N‑Heterocyclic Silyl Pincer Ligands

The
reaction of 1,2-C6H4(NHCH2PPh2)2 with chlorosilanes Cl2SiHR
(R = Ph, Cl) affords the benzosiladiazoles RHSi­(NCH2PPh2)2C6H4 (R = Ph, 1; Cl, 2). The phenyl derivative 1 undergoes
chelate-assisted Si–H activation with [RuPhCl­(CO)­(PPh3)2] and [RhCl­(PPh3)3] to afford
the structurally characterized silyl pincer complexes [RuCl­(CO)­(PPh3)­{κ3-P,Si,P′-SiPh­(NCH2PPh2)2C6H4}] (3) and [RhHCl­(PPh3)­{κ3-P,Si,P′-SiPh­(NCH2PPh2)2C6H4}] (4). The reaction
of 4 with [Et2NH2]­[S2CNEt2] affords the complex [RhH­(S2CNEt2)­{κ3-P,Si,P′-SiPh­(NCH2PPh2)2C6H4}] (5), structural data for which demonstrate a pronounced trans influence for the σ-silyl donor.

1,2-双[(二苯基膦基甲基)氨基]苯（1,2-C₆H₄(NHCH₂PPh₂)₂）与氯硅烷Cl₂SiHR（R = Ph、Cl）发生反应，可得到苯并硅二氮杂环类化合物RHSi(NCH₂PPh₂)₂C₆H₄（其中R=Ph时为产物1，R=Cl时为产物2）。苯基取代物1可与[RuPhCl(CO)(PPh₃)₂]和[RhCl(PPh₃)₃]发生螯合辅助的Si-H活化反应，生成经结构表征的硅基钳形配合物[RuCl(CO)(PPh₃){κ³-P,Si,P′-SiPh(NCH₂PPh₂)₂C₆H₄}]（3）与[RhHCl(PPh₃){κ³-P,Si,P′-SiPh(NCH₂PPh₂)₂C₆H₄}]（4）。配合物4与二乙基二硫代氨基甲酸二乙铵([Et₂NH₂][S₂CNEt₂])反应，得到配合物[RhH(S₂CNEt₂){κ³-P,Si,P′-SiPh(NCH₂PPh₂)₂C₆H₄}]（5），其结构数据证实σ-硅基给体具有显著的反位效应。