Side-on Bound Complexes of Phenyl- and Methyl-diazene

Treatment of trans-[FeCl2(dmpe)2] with phenylhydrazine and 1 equiv of base afforded the side-on bound phenylhydrazido complex cis-[Fe­(η2-NH2NPh)­(dmpe)2]+. Further deprotonation of the phenylhydrazido complex afforded the side-on bound phenyldiazene complex cis-[Fe­(η2-HNNPh)­(dmpe)2] as a mixture of diastereomers. Treatment of cis-[RuCl2(dmpe)2] with phenylhydrazine or methylhydrazine afforded the end-on bound phenylhydrazine or methylhydrazine complexes cis-[RuCl­(η1-NH2NHR)­(dmpe)2]+ (R = Ph, Me). Treatment of the substituted hydrazine complexes with base afforded the side-on bound phenylhydrazido complex cis-[Ru­(η2-NH2NPh)­(dmpe)2]+ as well as the phenyldiazene and methyldiazene complexes cis-[Ru­(η2-HNNR)­(dmpe)2] (R = Ph, Me). cis-[RuCl­(η1-NH2NHR)­(dmpe)2]+ (R = Ph, Me), cis-[M­(η2-NH2NPh)­(dmpe)2]+ (M = Fe, Ru) and cis-[Ru­(η2-HNNPh)­(dmpe)2] were characterized structurally by X-ray crystallography. cis-[Ru­(η2-HNNPh)­(dmpe)2] is the first side-on bound phenyldiazene complex to be structurally characterized. In the structure of cis-[Ru­(η2-HNNPh)­(dmpe)2], the geometry of the coordinated diazene fragment is significantly nonplanar (CNNH angle 137°) suggesting that the complex is probably better described as a Ru­(II) metallodiaziridine than a Ru(0) diazene π-complex.