A Germylene Supported by Two 2-Pyrrolylphosphane Groups as Precursor to PGeP Pincer Square-Planar Group 10 Metal(II)...

An efficient synthesis of 2-di-tert-butylphosphanylmethylpyrrole (HpyrmPtBu₂ ), by treating 2-dimethylaminomethylpyrrole (HpyrmNMe₂ ) with tBu₂ PH at 135 °C in the absence of any solvent, has allowed the preparation of the new PGeP germylene Ge(pyrmPtBu₂ )₂ (1), by treating [GeCl₂ (dioxane)] with LipyrmPtBu₂ , in which the Ge atom is stabilized by intramolecular interactions with one (solid state) or both (solution) of its phosphane groups. Reactions of germylene 1 with Group 10 metal dichlorido complexes containing easily displaceable ligands have led to [MCl{κ³ P,Ge,P-GeCl(pyrmPtBu₂ )₂ }] [M=Ni (2), Pd (3), Pt (4)], which have an unflawed square-planar metal environment. Treatment of germylene 1 with [AuCl(tht)] (tht=tetrahydrothiophene) rendered [Au{κ³ P,Ge,P-GeCl(pyrmPtBu₂ )₂ }] (5), which is a rare case of a T-shaped gold(I) complex. The hydrolysis of 5 gave the linear gold(I) derivative [Au(κP-HpyrmPtBu₂ )₂ ]Cl (6). Complexes 2-5 contain a PGeP pincer chloridogermyl ligand that arises from the insertion of the Ge atom of germylene 1 into a M-Cl bond of the corresponding metal reagent. The bonding in these molecules has been studied by DFT/NBO/QTAIM calculations. These results demonstrate that the great flexibility of germylene 1 makes it a better precursor to PGeP pincer complexes than the previously known germylenes of this type.