Low‐valent Germanylidene Anions : Efficient Single‐site Nucleophiles for Activation of Small Molecules

Abstract

Rare mononuclear and helical chain low-valent germanylidene anions supported by cyclic (alkyl)(amino) carbene and hypermetallyl ligands were synthesized by stepwise reduction from corresponding germylene precursors via stable acyclic germanium radicals. The germanylidene anions can be described with ylidene and ylidone resonance forms of which the latter becomes prevalent when engaging with electrophiles. Reactions of CO 2 resulted in the formation of μ-CO 2 -κC:κO adducts, a previously uncharacterized coordination mode for low-valent germanium and inaccessible for related neutral ylidones. These results implicate low-valent germanylidene anions as efficient single-site nucleophiles for activation of small molecules.