Utilizing Steric Bulk to Stabilize Molybdenum Aminogermylyne and Aminogermylene Complexes

Two extremely bulky bis(aryl)amines, HN(Ar*)(Ph) (HLPh) and HN(Ar*)(Mes) (HLMes) (Ar* = C6H2{C(H)Ph-2}(2)Me-2,6,4; Mes = mesityl), have been prepared by palladium-catalyzed cross-coupling reactions and structurally characterized. These have been utilized in the preparation of the amido-germanium(II) chlorides, [(LGeCl)-Ge-Ph] and [(LGeCl)-Ge-Mes]. Reactions of these, and the known complex, [L'GeCl] (L' = -N(Ar*)(SiMe3)), with Na[CpMo(CO)(3)] have afforded the first examples of structurally characterized two-coordinate molybdenum substituted germylenes, [Cp(CO)(3)MoGeN(Ar*)(R)] (R = SiMe3 or Ph). The former readily eliminates a molecule of CO when heated or irradiated with UV light to give an unprecedented aminogermylyne complex, [Cp(CO)(2)Mo GeN(Ar*)(SiMe3)]. The spectroscopic and structural data for this complex, in combination with the results of computational studies, show that this compound is best viewed as having a bent Mo-Ge "triple" bond, with little multiple bond character to its Ge-N interaction. Computational studies have also indicated that the Mo-Ge-N bending in the complex is due to the extreme steric bulk of its amido substituent.