Monomeric ruthenium(II) complexes containing diazene and isocyanide ligands: preparation and properties. Crystal structure of [Ru(4-CH3C6H4NNH)-(4-CH3C6H4NC){P(OEt)3}4](PF6)2

Article abstract of DOI:10.1016/0022-328X(88)83068-7

The complexes [Ru(ArNNH)(RNC){P(OEt)₃}₄](BPh₄)₂ (1: Ar = 4-CH₃C₆H₄, 4-CH₃OC₆H₄, 4-FC₆H₄; R = 4-CH₃C₆H₄, 4-CH₃OC₆H₄, C₆H₅), [Ru(RNC)₂-{P(OEt)₃}₄] (BPh₄)₂ (2) and [Ru(RNC)₃{P(OEt)₃}₃](BPh₄)₂ (3) (R = 4-CH₃-C₆H₄ derivatives were prepared by treating the bis(diazene) [Ru(ArNNH)₂-{P(OEt)₃}₄]²⁺ cations with isocyanides: they were characterized by IR and ¹H and ³¹P{¹H} NMR spectroscopy. The crystal structure of [Ru(4-CH₃C₆H₄NNH)(4-CH₃C₆H₄NC){P(OEt)₃}4] (PF₆)₂ was determined by X-ray diffraction. Crystals are monoclinic, of space group P2₁/n with unit-cell dimensions a 23.527(4), b 22.597(3), c 11.565(1) A, β 92.78(1)°, and Z = 4. The structure was solved by the heavy-atom method and refined by least-squares procedures to an R value of 0.0906 for 4812 independent observed reflections. The ruthenium atom lies within an essentially octahedral array of ligands with the diazene and isocyanide groups cis to one another. Reactions of the mono(diazene) derivatives 1 with NaBH₄ and LiCl gave the new complexes [RuH(ArNNH)(RNC){P(OEt)₃}3]BPh₄ and [RuCl(RNC){P(OEt)₃}₄]BPh₄.