Synthesis, Reactivity, and Complexation with Fe(0) of a Tight‐bite Bis(N‐heterocyclic silylene)

The synthesis, reactivity, and complexation with Fe(0) precursor of a tight‐bite bis(N‐heterocyclic silylene) (bis(NHSi)) ligand 1 are reported. The reaction of 1 with p‐toluidine led to the activation of both N−H bonds across Si(II) atoms to afford a four‐membered heterocyclic cyclodisilazane 2, with hydride substituents attached to five‐coordinate Si atoms. A 1 : 2 reaction of 1 with Fe(CO)5 led to an intriguing dinuclear complex 3 featuring a five‐membered (N−Si−Fe−Fe−Si) ring with a Fe−Fe bond distance of 2.6892(13) Å. All compounds (1‐3) were thoroughly characterized by various spectroscopic methods and X‐ray diffraction studies conclusively established their molecular structures. DFT calculations were carried out to shed light on bonding and energetic aspects in 1–3. This paper describes the unique reactions of a tight‐bite bis(NHSi) with p‐toluidine and Fe(CO)5. With p‐toluidine, it resulted in the oxidative addition of both N−H bonds across two Si(II) atoms to afford cyclodisilazane, whereas with Fe(CO)5 a four‐membered NSi2Fe2 ring with a Fe−Fe bond of 2.6892(13) Å is formed.