How Malonaldehyde Bonds Change during Proton Transfer

Abstract

The proton transfer mechanism in malonaldehyde has been investigated from the points of view of the topological analysis of the electron localization function and of the catastrophe theory. The calculations were carried out at the B3LYP hybrid functional level with the ccp-VTZ basis set. Complementary calculations were performed at the HF, MP2, BLYP, and B3LYP levels with the STO-3G, 6-31G, and 6-31G** basis sets in order to discuss the stability of the method. The mechanism of the reaction does not involve any reorganization of the skeleton: it is localized in the hydrogen bond region and involves three chemical structures corresponding to the reactant, the transition state, and the product. It is shown that the proton detachment is in fact the covalent breaking of the OH bond, and by symmetry its attachment on the other oxygen is also a covalent process. The analysis of the catastrophe shows that the reaction is driven by two active coordinates related to the OH and OO distance and provides a method for the determination of the limiting paths.

Dynamic Behavior of an N‐Metalated β‐Enaminoimine Complex − Preparation of N‐Phosphanylenamine and β‐Enaminoimine Derivatives

“…These observations can be rationalized if it is assumed that 14 possesses a low-barrier hydrogen bond with a double-well potential. This is in agreement with the mechanism of proton transfer in malonaldehyde recently proposed by Silvi and co-workers, [23] involving a two-step reaction with a concerted charge transfer from one bond to another within the planar framework of the aldehyde. This description may also be applied to the analogous β-enaminoimine systems.…”

Curly arrows meet electron density transfers in chemical reaction mechanisms: from electron localization function (ELF) analysis to valence-shell electron-pair repulsion (VSEPR) inspired interpretation

“…The transitions between successive structural stability domains occurs at turning points of the control parameter space are described in terms of bifurcation catastrophes in the sense of René Thom. 116 The process of the creation-annihilation of electronic domains depicted by ELF has been formalized in the bonding evolution theory (BET) of Krokidis et al 78 This method has been widely applied to investigate many chemical reactions such as proton transfers, 117 4 How BET procedure reveals electron density transfers…”

Characterisation of the reaction mechanism between ammonia and formaldehyde from the topological analysis of ELF and catastrophe theory perspective

“…To aid better understanding of the methodology used here, the reader is encouraged to familiarise themselves with the papers published by Silvi's group [30][31][32][33][34][35]. Particularly those describing the BET theory [5] and BET applications for reaction mechanisms such as isomerisation in XNO (X=H, Cl) [36], hydrogen transfer in H 5 O 2 + [33], in malonaldehyde [37], in the HF-(OH)…”