Preparation and reactivity of half-sandwich hydrazine complexes of ruthenium and osmium

Hydrazine complexes [MCl(eta(6)-p-cymene)(RNHNH2)L]BPh4 (1-6) [M = Ru, Os; R H, Me, Ph; L P(OEt)(3), PPh(OEt)(2), PPh2OEt] were prepared by allowing dichloro complexes MCl2(eta(6)-p-cymene)L to react with hydrazines RNHNH2 in the presence of NaBPh4. Treatment of ruthenium complexes [RuCl(eta(6)-p- cymene)(RNHNH2)L]BPh4 with Pb(OAc)(4) led to acetate complex [Ru(kappa(2)-O2CCH3)(eta(6)-p-cymene)L]BPh4 (7). Instead, the reaction of osmium derivatives [OsCl(eta(6)-p-cymene)(CH3NHNH2)L]BPh4 with Pb(OAc)(4) afforded the methyldiazenido complex [Os(CH3N2)(eta(6)-p-cymene)L}]BPh4 (8). Treatment with HCl of this diazenido complex 8 led to the methyldiazene cation [OsCl(CH3N=NH)(eta(6)-p-cymene)L}](+) (9(+)). The complexes were characterised spectroscopically and by X-ray crystal structure determination of [OsCl(eta(6)-p-cymene)(PhNHNH2){PPh(OEt)(2)}]BPh4 (6b) and [Ru(kappa(2)-O2CCH3)(eta(6)-p-cymene){PPh(OEt)(2)}] BPh4 (7b). (C) 2011 Elsevier B. V. All rights reserved.