Side-on bound complexes of phenyl- and methyl-diazene

Treatment of trans-FeCl(2)(dmpe)(2)] with phenylhydrazine and 1 equiv of base afforded the side-on bound phenylhydrazido complex cis-Fe(η(2)-NH(2)NPh)(dmpe)(2)](+). Further deprotonation of the phenylhydrazido complex afforded the side-on bound phenyldiazene complex cis-Fe(η(2)-HN═NPh)(dmpe)(2)] as a mixture of diastereomers. Treatment of cis-RuCl(2)(dmpe)(2)] with phenylhydrazine or methylhydrazine afforded the end-on bound phenylhydrazine or methylhydrazine complexes cis-RuCl(η(1)-NH(2)NHR)(dmpe)(2)](+) (R = Ph, Me). Treatment of the substituted hydrazine complexes with base afforded the side-on bound phenylhydrazido complex cis-Ru(η(2)-NH(2)NPh)(dmpe)(2)](+) as well as the phenyldiazene and methyldiazene complexes cis-Ru(η(2)-HN═NR)(dmpe)(2)] (R = Ph, Me). cis-RuCl(η(1)-NH(2)NHR)(dmpe)(2)](+) (R = Ph, Me), cis-M(η(2)-NH(2)NPh)(dmpe)(2)](+) (M = Fe, Ru) and cis-Ru(η(2)-HN═NPh)(dmpe)(2)] were characterized structurally by X-ray crystallography. cis-Ru(η(2)-HN═NPh)(dmpe)(2)] is the first side-on bound phenyldiazene complex to be structurally characterized. In the structure of cis-Ru(η(2)-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.