Quantitative Descriptions of Dewar‐Chatt‐Duncanson Bonding Model: A Case Study of Zeise and Its Family Ions

Abstract

AbstractHistorically, Dewar‐Chatt‐Duncanson (DCD) model is a heuristic device to advance the development of organometallic chemistry and deepen our understanding of the metal‐ligand bonding nature. Zeise's ion, the first man‐made organometallic compound and a quintessential transition metal‐olefin complex, was qualitatively explained using the DCD bonding scheme in 1950s. In this work, we quantified the explicit contributions of the σ donation and π back‐donation to the metal‐ligand bonding in Zeise and its family ions, [PtX3L]− (X=F, Cl, Br, I, and At; L=C2H4, CO, and N2), using state‐of‐the‐art quantum chemical calculations and energy decomposition analysis. The relative importance of the σ donation and π back‐donation depends on both X and L, with [PtCl3(C2H4)]− being a critical case in which the σ donation is marginally weaker than the π back‐donation. The changes along this series are controlled by the energy levels of the correlated molecular orbitals of PtX3− and ligand L. This study deepens our understanding of the bonding properties for transition metal complexes beyond the qualitative description of the DCD model.