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

Abstract

Hydrazine complexes [MCl(η 6- p-cymene)(RNHNH 2)L]BPh 4 ( 1– 6) [M = Ru, Os; R = H, Me, Ph; L = P(OEt) 3, PPh(OEt) 2, PPh 2OEt] were prepared by allowing dichloro complexes MCl 2(η 6- p-cymene)L to react with hydrazines RNHNH 2 in the presence of NaBPh 4. Treatment of ruthenium complexes [RuCl(η 6- p-cymene)(RNHNH 2)L]BPh 4 with Pb(OAc) 4 led to acetate complex [Ru(κ 2–O 2CCH 3)(η 6- p-cymene)L]BPh 4 ( 7). Instead, the reaction of osmium derivatives [OsCl(η 6- p-cymene)(CH 3NHNH 2)L]BPh 4 with Pb(OAc) 4 afforded the methyldiazenido complex [Os(CH 3N 2)(η 6- p-cymene)L}]BPh 4 ( 8). Treatment with HCl of this diazenido complex 8 led to the methyldiazene cation [OsCl(CH 3N NH)(η 6- p-cymene)L}] + ( 9 +). The complexes were characterised spectroscopically and by X-ray crystal structure determination of [OsCl(η 6- p-cymene)(PhNHNH 2){PPh(OEt) 2}]BPh 4 ( 6b) and [Ru(κ 2–O 2CCH 3)(η 6- p-cymene){PPh(OEt) 2}]BPh 4 ( 7b).