A Combined Charge and Energy Decomposition Scheme for Bond Analysis

Abstract

2007, 13, 347 ]. The ETS-NOCV charge and energy decomposition scheme based on the Kohn-Sham approach makes it not only possible to decompose the deformation density, Δρ, into the different components (such as σ, π, δ, etc.) of the chemical bond, but it also provides the corresponding energy contributions to the total bond energy. Thus, the ETS-NOCV scheme offers a compact, qualitative, and quantitative picture of the chemical bond formation within one common theoretical framework. Although, the ETS-NOCV approach contains a certain arbitrariness in the definition of the molecular subsystems that constitute the whole molecule, it can be widely used for the description of different types of chemical bonds. The applicability of the ETS-NOCV scheme is demonstrated for single (H3X-XH3, for X = C, Si, Ge, Sn) and multiple (H2X═XH2, H3CX≡XCH3, for X = C, Ge) covalent bonds between main group elements, for sextuple and quadruple bonds between metal centers (Cr2, Mo2, W2, [Cl4CrCrCl4](4-)), and for double bonds between a metal and a main group element ((CO)5Cr═XH2, for X = C, Si, Ge, Sn). We include finally two applications involving hydrogen bonding. The first covers the adenine-thymine base pair and the second the interaction between C-H bonds and the metal center in the alkyl complex.

Computational Analysis of n→π* Back-Bonding in Metallylene–Isocyanide Complexes R2MCNR′ (M = Si, Ge, Sn; R =tBu, Ph; R′ = Me,tBu, Ph)

“…The method can, however, be combined with the Morokuma-Ziegler-Rauk interactionenergy decomposition analysis (EDA), 24 which gives the combined ETS-NOCV method. 43 The (instantaneous) interaction energy ΔEint is defined as the change in energy as the molecule is formed from the promolecule. In the decomposition process, this energy is partitioned into three [16] components: ΔEint = ΔEPauli + ΔEelstat + ΔEorb.…”

Understanding the Reactivity of Planar Polycyclic Aromatic Hydrocarbons: Towards the Graphene Limit

“…Thus, the EDA-NOCV approach, [40] which provides pairwise energy contributions for each pair of interacting orbitals to the total bond energy, indicates that two main molecular orbital interactions dominate the total orbital interactions in these processes, namely the π(PAH)π*(maleic anhydride) and the reverse π(maleic anhydride)π*(PAH) interactions (see Figure 6). As expected for a normal electronic demand Diels-Alder process the π(PAH)π*(maleic anhydride) interaction is clearly higher than the reverse interaction (i.e.…”

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.…”