An Isolable Bis(silylene)-Stabilized Germylone and Its Reactivity

Area of Science:

• Organometallic Chemistry
• Main Group Chemistry
• Catalysis

Background:

• Zerovalent main group complexes are rare and highly reactive.
• Stabilization of low-valent germanium species presents significant synthetic challenges.
• Understanding the electronic properties of such complexes is crucial for predicting reactivity.

Purpose of the Study:

• To synthesize and characterize the first stable zerovalent germanium complex.
• To investigate the electronic structure and bonding of the germylone.
• To explore the reactivity of the germylone with Lewis acids and in catalytic applications.

Main Methods:

• Synthesis of the zerovalent germanium complex via dechlorination.
• Structural and spectroscopic characterization (e.g., X-ray diffraction, NMR).
• Density Functional Theory (DFT) calculations and Natural Bond Orbital (NBO) analysis.
• Reactions with Lewis acids (AlBr3, 9-BBN, BPh3) and transition metal complexes (Ni(cod)2).

Main Results:

• Successful synthesis of the first stable zerovalent germanium complex, [SiII(Xant)SiII]Ge0.
• NBO analysis revealed two lone pairs on the germanium atom, enabling Lewis adduct formation.
• Demonstrated unusual reactivity, including formation of boryl(silyl)germylene and a Ge2Ni-metallacycle.
• Formation of a frustrated Lewis pair (FLP) with BPh3, facilitating heterolytic H2 cleavage at room temperature.

Conclusions:

• The synthesized germylone is a stable, electron-rich species with unique reactivity.
• This work expands the scope of low-valent main group chemistry.
• The germylone's application in FLP chemistry opens new avenues for small molecule activation.