Synthesis and structural characterization of metallogermylenes, Cp-substituted germylene, and a germanium(II)-borane adduct from pyridyl-1-azaallyl germanium(II) chloride

The reaction of [{N(SiMe ₃)C(Ph)C(SiMe ₃)(C ₅H ₄N-2)}GeCl] (1) with Na[M(η ⁵-C ₅H ₅)(CO) ₃]•2DME (M = Mo, W) afforded the metallogermylenes [{N(SiMe ₃)C(Ph)C(SiMe ₃)(C ₅H ₄N-2)}Ge-M(η ⁵-C ₅H ₅)(CO) ₃] (M = Mo (2), W (3)). Compounds 2 and 3 have been characterized by X-ray crystallography and NMR and IR spectroscopy. Structural analyses of compounds 2 and 3 are consistent with the presence of lone-pair electrons at the germanium(II) center. The Ge-Mo and Ge-W bond distances of 2.875(1) and 2.852(1) Å are consistent with Ge-metal single bonds. The chlorogermylene 1 was also used in the synthesis of a substituted germylene, [{N(SiMe ₃)C(Ph)C(SiMe ₃)(C ₅H ₄N-2)} Ge(η ¹-C ₅H ₅)] (4), by reaction with sodium cyclopentadienylide. The reaction of compound 1 with tris(pentafluorophenyl) borane led to the formation of a Lewis acid-base adduct, [{N(SiMe ₃)C(Ph)C(SiMe ₃)(C ₅H ₄N-2)}Ge(Cl) →B(C ₆F ₅) ₃] (5).