Comparative reactivity studies of dppf-containing CpRuII and (C6Me6)RuII complexes towards different donor ligands (dppf=1,1′-bis(diphenylphosphino)ferrocene)

Abstract

[CpRu(dppf)Cl] (Cp=η5-C5H5) (1) and [(HMB)Ru(dppf)Cl]PF6 ((HMB)=η6-C6Me6) (3) react with different donor ligands to give rise to N-, P- and S-bonded complexes. The stoichiometric reactions of 1 and 3 with NaNCS give the mononuclear complexes [CpRu(dppf)(NCS)] (2) and [(HMB)Ru(dppf)(NCS)]PF6 (4), respectively, in yields above 80%, while 3 also gives a dppf-bridged diruthenium complex [(HMB)Ru(NCS)2]2 (μ-dppf) (5) in 67% yield from reaction with four molar equivalents of NaNCS. Compound 5 is also obtained in 70% yield from the reaction of 4 with excess NaNCS. With CH3CN in the presence of salts, both 1 and 3 give their analogous solvento derivatives [CpRu(dppf) (CH3CN)] BPh4 (6) and [(HMB)Ru(dppf) (CH3CN)] (PF6)2 (7). With phosphines, the reaction of 1 gives chloro-displaced complexes [(CpRu(dppf)L]PF6 (L =PMe3 (8), PMe2Ph(9), whereas the reaction of 3 with PMe2Ph leads to substitution of dppf, giving [(HMB)Ru(PMe2Ph)2Cl] PF6 (10). The reaction of 1 with NaS2CNEt2 gives a dinuclear dppf-bridged complex [{CpRu(S2CNEt2)} 2(μ-dppf)] (11), whereas that of 3 results in loss of the HMB ligand giving a mononuclear complex [Ru(dppf) (S2CNEt2)2] (12). With elemental sulfur S8, 1 is oxidized to give a dinuclear CpRuIII dppf-chelated complex [{CpRu(dppf)}2(μ-S2)] (BPh4)Cl (13), whereas 3 undergoes oxidation at the ligand, giving a dppf-displaced complex [(HMB)Ru(CH3CN)2Cl] PF6 (14) and free dppfS2. The structures of 1, 2, 5-9, 11, 13 and 14 were established by X-ray single crystal diffraction analyses. Of these, 5 and 11 both contain a dppf-bridge between RuII centers, while 13 is a dinuclear CpRuIII disulfide-bridged complex; all the others are mononuclear. All complexes obtained were also spectroscopically characterized. © 2004 Elsevier B.V. All rights reserved.