Germyl halides complexes

Cross-coupling to form carbon heteroatom bonds occurs by oxidative addition of an organic halide, generation of an aryl- or vinylpalladium amido, alkoxo, tholato, phosphido, silyl, stannyl, germyl, or boryl complex, and reductive elimination (Scheme 2). The relative rates and thermodynamics of the individual steps and the precise structure of the intermediates depend on the substrate and catalyst. A full discussion of the mechanism for each type of substrate and each catalyst is beyond the scope of this review. However, a series of reviews and primary literature has begun to provide information on the overall catalytic process.18,19,22,23,77,186... 

Ge—metal bonds can be built in analogy as described for Ge—C bonds by the reaction of organolithium compounds with metal halides. With trans-dichlorobis(triethylphosphine)platinum(II), new germyl transition metal complexes were synthesized (equation 36)41. 

Germyl metallocene derivatives of the early transition metals, Ti, Zr and Hf (M) have been synthesized by the combination of metallocene halides and germyl anions (equations 4 and 5)38-40. The cyclopentadienyl complexes Cp2M(GePh3)Cl39 are difficult to purify due to their instability in solution however, use of the pentamethylcyclopen-tadienyl group(Cp ) enhances both the solubility and stability of these complexes40,41. 

The asymmetric germyl anion also permitted preparation of chiral germyl-transition-metal complexes (35, 36) by substitution of a halogen from a metal halide (eq. [15]). 

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