A Bis(silylenyl)pyridine Zero-Valent Germanium Complex and Its Remarkable Reactivity

Area of Science:

• Organometallic Chemistry
• Main Group Chemistry
• Coordination Chemistry

Background:

• The synthesis and reactivity of low-valent silicon and germanium compounds are of significant interest.
• Nitrogen-containing heterocyclic ligands offer unique coordination environments for main group elements.

Purpose of the Study:

• To report the synthesis, reactivity, and electronic structure of a novel germylone iron carbonyl complex.
• To investigate the coordination behavior and structural features of germanium within a pincer ligand framework.
• To explore the reactivity of the synthesized complex with further germanium precursors.

Main Methods:

• Synthesis of the germylone iron carbonyl complex via reaction of a bis(N-heterocyclic silylenyl)pyridine pincer ligand with GeCl2·(dioxane) followed by reduction.
• Single-crystal X-ray diffraction analysis to determine the molecular structure and coordination geometry.
• Density Functional Theory (DFT) calculations to investigate electronic features.

Main Results:

• The novel germylone iron carbonyl complex [SiNSi]Ge⁰ →Fe(CO)₄ was synthesized in 49% yield.
• X-ray diffraction revealed a trigonal-pyramidal geometry at the Ge⁰ center and an unusual five-coordinate Si^II atom.
• Reaction with GeCl₂·(dioxane) unexpectedly yielded the first push-pull germylone-germylene donor-acceptor complex, [SiNSi]Ge→GeCl₂ →Fe(CO)₄.

Conclusions:

• The study reports the successful synthesis and characterization of a unique germylone iron carbonyl complex.
• The complex displays interesting structural features and reactivity, including the formation of a novel donor-acceptor system.
• This work expands the understanding of low-valent germanium chemistry and its coordination to transition metals.