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

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) Å, 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. © 1988.