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

The synthesis, reactivity, and electronic structure of the unique germylone iron carbonyl complex SiNSi]Ge⁰ →Fe(CO)₄ is reported. The compound was obtained in 49 % yield from the reaction of the bis(N‐heterocyclic silylenyl)pyridine pincer ligand SiNSi (1,6‐C₅NH₃‐EtNSi(N^tBu)₂CPh]₂) with GeCl₂?(dioxane) to give the corresponding chlorogermyliumylidene chloride precursor SiNSi]Ge^IICl⁺ Cl^? , which was further reduced with K₂Fe(CO)₄. Single‐crystal X‐ray diffraction analysis of SiNSi]Ge →Fe(CO)₄ revealed that the Ge⁰ center adopts a trigonal‐pyramidal geometry with a Si‐Ge‐Si angle of 95.66(2)°. Remarkably, one of the Si^II donor atoms in the complex is five‐coordinated because of additional (pyridine)N→Si coordination. Unexpectedly, the reaction of SiNSi]Ge →Fe(CO)₄ with GeCl₂?(dioxane) (one molar equivalent) yielded the first push–pull germylone–germylene donor–acceptor complex, SiNSi]Ge →GeCl₂→Fe(CO)₄ through the insertion of GeCl₂ into the dative Ge⁰→Fe bond. The electronic features of the new compounds were investigated by DFT calculations.