Reaction of iron and ruthenium halogenide complexes with GaCp∗ and AlCp∗: Insertion, Cp∗ transfer reactions and orthometallation

The reactions of the Fe(II) and Ru(II) halogenide complexes [Fe(PPh3)2Br2], [Fe(NCCH3)2Br2], [Ru(PPh3)3Cl2], and [Ru(dmso)4Cl2] with GaCp∗ and AlCp∗, respectively, are investigated. The reactions of [FeBr2L2] with ECp∗ exclusively proceed via Cp∗ transfer, leading to [FeCp∗(GaCp∗)(GaBr2)(PPh3)] (1) (L = PPh3, E = Ga), [FeCp∗(GaCp∗)2 (GaBr2)] (2) (L = NCCH3, E = Ga) and [FeCp∗(μ3-H)(κ2-(C6H4)PPh2)(AlCp∗)(AlBr2)] (3) (L = PPh3, E = Al), the latter of which is formed via orthometallation of one PPh3 ligand. The reaction of [Ru(dmso)4Cl2] leads to the homoleptic complex [Ru(GaCp∗)6Cl2] (4) in high yields, while [Ru(PPh3)3Cl2] gives 4 in rather low yields. The reason for this difference in reactivity is investigated and it is shown that Cp∗ transfer and orthometallation are the limiting side reactions of the reaction of [Ru(PPh3)3Cl2] with GaCp∗. All compounds were characterized by NMR spectroscopy, and single crystal X-ray diffraction studies were performed for 1, 3, and 4.

The reactions of the Fe(II) and Ru(II) halogenide complexes [Fe(PPh3)2Br2], [Fe(NCCH3)2Br2], [Ru(PPh3)3Cl2], and [Ru(dmso)4Cl2] with GaCp∗ and AlCp∗, respectively, are investigated, leading to half sandwich Fe(II) complexes. The reaction of the Ru(II) complexes does not lead to Cp∗ transfer reaction in significant amount but instead results in the formation of the homoleptic insertion product [Ru(GaCp∗)6Cl2].Figure optionsDownload as PowerPoint slide