Theoretical Insight into 20‐Electron Transition Metal Complexes (C5H5)2TM(E1E2)2 (TM = Cr, Mo, W; E1E2 = CO, N2, BF): Stabilities, Electronic Structures, and Bonding Nature

Abstract

A systematic first‐principles study is performed to investigate the 20‐electron transition metal complexes (C5H5)2TM(E1E2)2 (TM = Cr, Mo, W; E1E2 = CO, N2, BF). For the thermodynamic stable (C5H5)2TM(E1E2)2 complexes (TM = Cr, Mo, W; E1E2 = CO, BF), their 20‐electron nature is derived from their occupied nonbonding molecular orbital mainly donated by ligands. Furthermore, the nature of the TME1 bond is thoroughly analyzed by the energy decomposition analysis (EDA) method. The absolute value of interaction energies (|ΔEint|) between (C5H5)2TM(E1E2) and E1E2 has the same trend as the corresponding bond dissociation energy and Wiberg bond orders of TME1 bonds, following the order W > Mo > Cr with same ligands and BF > CO with same TM. The largest contribution to the ΔEint values is the repulsive term ΔEPauli. Similar contributions from covalent and electrostatic terms to the TME1 bonds are found, which can be described as the classic dative bond with nearly same σ and π contributions.