title: Conversion of a monodentate amidinate-germylene ligand into chelating imine-germanate ligands (on mononuclear manganese complexes).
abstract: The unprecedented transformation of a terminal two-electron-donor amidinate-germylene ligand into a chelating three-electron-donor κ(2)-N,Ge-imine-germanate ligand has been achieved by treating the manganese amidinate-germylene complex [MnBr{Ge((i)Pr2bzam)(t)Bu}(CO)4] (1; (i)Pr2bzam = N,N'-bis(isopropyl)benzamidinate) with LiMe or Ag[BF4]. In these reactions, which afford [Mn{κ(2)Ge,N-GeMe((i)Pr2bzam)(t)Bu}(CO)4] (2) and [Mn{κ(2)Ge,N-GeF((i)Pr2bzam)(t)Bu}(CO)4] (3), respectively, the anionic nucleophile, Me(-) or F(-), ends on the Ge atom while an arm of the amidinate fragment migrates from the Ge atom to the Mn atom. In contrast, the reaction of 1 with AgOTf (OTf = triflate) leads to [Mn(OTf){Ge((i)Pr2bzam)(t)Bu}(CO)4] (4), which maintains intact the amidinate-germylene ligand. Complex 4 is very moisture-sensitive, leading to [Mn2{μ-κ(4)Ge2,O2-Ge2(t)Bu2(OH)2O}(CO)8] (5) and [(i)Pr2bzamH2]OTf (6) in wet solvents. In 5, a novel digermanate(II) ligand, [(t)Bu(OH)GeOGe(OH)(t)Bu](2-), doubly bridges two Mn(CO)4 units. The structures of 1-6 have been characterized by spectroscopic (IR, NMR) and single-crystal X-ray diffraction methods.
authors.affiliation: Departamento de Química Orgánica e Inorgánica-IUQOEM, Universidad de Oviedo-CSIC , E-33071 Oviedo, Spain.
authors.forename: Javier A
authors.initials: JA
authors.lastname: Cabeza
authors.forename: Pablo
authors.initials: P
authors.lastname: García-Álvarez
authors.forename: Enrique
authors.initials: E
authors.lastname: Pérez-Carreño
authors.forename: Diego
authors.initials: D
authors.lastname: Polo
mesh_terms: D000578:Amidines / Q000737:chemistry*; D002614:Chelating Agents / Q000737:chemistry*; D005857:Germanium / Q000737:chemistry*; D007097:Imines / Q000737:chemistry*; D008024:Ligands; D008345:Manganese / Q000737:chemistry*; D008958:Models, Molecular; D008968:Molecular Conformation; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*
chemical_list: D000578:Amidines; D002614:Chelating Agents; D007097:Imines; D008024:Ligands; D009942:Organometallic Compounds; D005857:Germanium; D008345:Manganese