Carbon monoxide, carbon monosulfide, molecular nitrogen, phosphorus trifluoride, and methyl isocyanide as .sigma. donors and .pi. acceptors. A theoretical study by the Hartree-Fock-Slater transition-state method

Abstract

Hartree-Fock-Slater calculations have been carried out on Ni(CO)3L for a number of different ligands (L) in order to investigate the abilities of the ligands to act as donors and x acceptors. The order, based on extent of electron transfer, for donation is CS =* CO > CNCH3 > N2 ~PF3 and for x back-bonding is CNCH3 > CS > CO > PF3 > N2. The contributions to the total bonding energy between Ñi(CO)3 and L from donation and x back-donation are evaluated by the Hartree-Fock-Slater transition-state method, and the same method is used to optimize the Ni-L bond distances.Calculations on the stretching frequency vCo of carbon monoxide complexed to Ni(CO)3 showed that vCo is decreased by the x back-donation but is increased by the steric interaction energy between Ni(CO)3 and CO. Thus the decrease in vCo is not a reliable measure of the extent of x back-bonding in the metal-ligand bond. The calculated influence on vCo from donation was negligible.

Electronic structure theory to decipher the chemical bonding in actinide systems

“…These developments have taken place aiming to overcome limitations of the original schemes and provide more chemical significance to the energy components, which are not uniquely defined. We can cite, for example, CSOV (Constrained Space Orbital Variations) [107], RVS (Reduced Variational Space Self-Consistent-Field) [108], SAPT (Symmetry-Adapted Perturbation Theory) [109], NEDA (Natural Energy Decomposition Analysis) [110][111][112], LMOEDA (Localized Molecular Orbital Energy Decomposition Analysis) [113], ALMO-EDA (Absolutely Localized Molecular Orbital [114]), FMO (Fragment Molecular Orbital [115][116][117]) and a Morokuma-type EDA developed by Ziegler and Rauk [118][119][120]. Certainly, this list is not exhaustive, but recalls some popular currently used EDA schemes.…”

Pyridine-Derived N-Heterocyclic Carbenes: An Experimental and Theoretical Evaluation of the Bonding in and Reactivity of Selected Normal and Abnormal Complexes of Nickel(II) and Palladium(II)

“…88,89 The bonding analysis focuses on the instantaneous interaction energy ΔE int of a 90 It comprises the destabilizing interactions between electrons of the same spin on either fragment. The orbital interaction ΔE orb accounts for charge transfer and polarization effects.…”

Palladium Catalysts for Dehydrogenation of Ammonia Borane with Preferential B−H Activation

“…Relativistic effects were included at the level of ZORA approximation as implemented in the ADF program. 19 The natural orbitals for chemical valence (NOCV) [20][21][22] analysis, supported by the extended transition state (ETS) Ziegler-Rauk bond-energy decomposition scheme, 22,23 was performed for catalyst (A), to describe the bond between the AB molecule and the metal containing fragment. The combined ETS-NOCV approach 20 allowed us to separate the independent components of the differential density, ∆ρ, into the electron charge transfer channels that contribute to the bonding between fragments in a molecule.…”