Insights into the Base-Stabilized Silylene Nature of the IrSi Bond in Ir(III)–(κ2-NSi) Complexes with 2-Quinolone and 2-Pyridone Type Ligands

A series of Ir–(κ²-NSi) complexes with 2-quinolone type ligands have been prepared and characterized to increase our scope of 16e unsaturated Ir–(κ²-NSi) species to carry out a comprehensive study of the nature of the IrSi bond. Density functional theory calculations with natural bond orbital and quantum theory of atoms in molecules analyses of a range of Ir–silyl(ene) complexes allows the description of the IrSi bond of the examinated complexes as a polarized covalent interaction. The findings of this study also suggest that the most accurate description of this bond in the Ir–(κ²-NSi) complexes is base-stabilized silylene. Investigating the silicon environment has been the key for determining the nature of the IrSi bond. This insight also enables to elucidate the base-stabilized TM–silylene character in other complexes.