Co-Ligand-Dependent Rh(I)–Si(IV) Interactions in Silicon Z-Type Complexes

Rh(I) Z-type complexes featuring σ-accepting group 13 Lewis acids have been well established over recent years and proven efficient in catalytic transformations. In this work, we report the isolation and characterization of the first Rh(I) silane Z-type complexes. Distinct properties compared to their group 13 counterparts are exhibited due to the high effective Lewis acidity of Si(IV), which leads to remarkably strong Rh(I)-Si(IV) bonding. The nature of this interaction is found to be highly dependent on the choice of coligands at Rh(I) (e.g., Cl, Me, Cp, H, and CNCy). Through a combination of experimental techniques and quantum chemical analyses (NBO, QTAIM, and ETS-NOCV), we systematically investigate this coligand dependency. These findings provide valuable insights into the design and optimization of catalytically active Rh(I) Z-type complexes.