Side-on Bound Diazene and Hydrazine Complexes of Ruthenium

The reaction of cis-[RuCl2(PP)2] (PP = depe, dmpe) with hydrazine afforded end-on bound ruthenium(II) hydrazine complexes. Treatment of the hydrazine complexes with strong base afforded the side-on bound ruthenium(0) diazene complexes cis-[Ru(η2-NHNH)(PP)2]. Treatment of cis-[Ru(η2-NHNH)(depe)2] with weak acid under chloride-free conditions afforded the side-on bound hydrazine complex cis-[Ru(η2-N2H4)(depe)2]2+. These are the first reported side-on bound diazene and hydrazine complexes of ruthenium, and they have been characterized by NMR spectroscopy (1H, 31P, 15N) and by X-ray crystallography. The interconversion between the ruthenium diazene and the ruthenium hydrazine by acid−base treatment was reversible.