Preparation of Pyrazole-Pyrazolate Half-Sandwich Complexes of Ruthenium and Osmium

Pyrazole (HRpz) [MCl(η6-p-cymene)(HRpz)L]BPh4 (1-8) and imidazole (HIm) complexes [MCl(η6-p-cymene)(HIm)L] BPh4 (9-10) [M = Ru, Os; R = H, 3-Me, 3,5-Me2; L = P(OEt)3, PPh(OEt)2, PPh2OEt, CNtBu] were prepared by allowing the dichloro compounds MCl2(η6-p- cymene)L to react with the appropriate azole in the presence of NaBPh 4. Treatment of the dichloro complexes with an excess of both pyrazole and NEt3 yielded the pyrazole-pyrazolate derivatives [M(Rpz)(η6-p-cymene)(HRpz)L]BPh4 (11-14). Conversely, the reaction of carbonyl compounds RuCl2(η6-p-cymene) (CO) with pyrazole or imidazole yielded the bisazole complexes [MCl(η6-p-cymene)(HRpz)2]BPh4 or [MCl(η6-p-cymene)(HIm)2]BPh4 (15-17). The complexes were characterised spectroscopically (IR and 1H, 13C, 31P NMR) and by X-ray crystal structure analysis [RuCl(η6-p-cymene)(HRpz){PPh(OEt)2}]BPh4 (1b), [Ru(pz)(η6-p-cymene)(HRpz){P(OEt)3}]BPh 4 (11a) and [RuCl(η6-p-cymene)(HRpz) 2]BPh4 (15). © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim