Application of Bond Energy Density Analysis (Bond-EDA) to Diels–Alder Reaction

Abstract

The bond energy density analysis (Bond-EDA), which can evaluate bond energies in molecules by using the results of theoretical calculations, is applied to investigate chemical bonds in Diels–Alder (DA) reaction. Evaluation of the bond energies confirms the bond alternation in the reactant and product quantitatively, and shows that the TS structure is close to the reactant. In the case of regioselective reaction, local stabilities in newly formed bonds in the TS show significant differences, which correspond to the relationship of the bond distances.

Bond Energy Density Analysis Combined with Informatics Technique

“…The authors’ group, i.e., Nakai, Ohashi, Imamura, and Kikuchi, further introduced an adjustable parameter depending on the atomic forces, to provide reasonable BEs for both single and multiple bonds. The authors’ group uses the terminology of bond energy density analysis (Bond-EDA) for the two-body energy decomposition scheme, because the scheme is regarded as the extension of a one-body energy decomposition scheme proposed by one of the authors, named as energy density analysis (EDA). − The Bond-EDA scheme was applied to the analyses in various chemical phenomena such as the Diels–Alder reaction, hexacoordinate hypervalent carbon compounds, and effective exchange integrals for radical dimers . Despite the long history and various improvements of the two-body decomposition scheme, a problem still exists for simultaneous evaluation of the BEs of various types of chemical bonds such as strong covalent and ionic bonds and weak through-space/bond interactions.…”

Natural bond orbital‐based energy density analysis for correlated methods: Second‐order Møller–Plesset perturbation and coupled‐cluster singles and doubles

“…As for energy, several groups have recently proposed simple energy partitioning schemes 3–38, which allow us to investigate electron behaviors by splitting total energies into atomic and/or bonding contributions. Those energy partitioning schemes for ab initio methods such as Hartree–Fock (HF) and density functional theory (DFT) have been applied to scientifically intriguing phenomena 39–49.…”

A reactive bond orbital investigation of the Diels‐Alder reaction between 1,3‐butadiene and ethylene: Energy decomposition, state correlation diagram, and electron density analyses

“…To date, theoretical methods affording such chemical interpretations have indeed been proposed. Included amongst them are frontier orbital theory,9–15 valence bond (VB) theory,16–19 wave function (or electron density) analysis,20–25 conceptual DFT,26–29 and energy decomposition analysis 30–32. These approaches have shed light on various aspects of Diels‐Alder reactions that PES calculations alone are not able to characterize.…”