1,4- vs 1,3-prototropic mechanism for intramolecular double proton transfer reaction in monothiooxalic acid. Theoretical investigation of potential energy surface.
Proton transfer is a very common and important chemical step in many systems. Despite its apparent simplicity, a correct description of this chemical process is difficult from a theoretical point of view. It requires a correct and simultaneous description of a bond breaking and a bond formation. The situation is even much more complicated when two protons are implied. This is the case for monothiooxalic acid, for which two different types (1,3- and 1,4-prototropy) of proton transfers can be invoked. A further problem is the type of the reaction (concerted or not). This paper reports a complete investigation of the potential energy surfaces: characterization of equilibrium points and transitions states. The main conclusion is: the 1,4-prototropic mechanism, mainly considered as a one step concerted exchange of protons, is the most favored from an energetic point of view.
Raynaud
Christophe
C
Laboratoire de Physique Quantique, UMR 5626, IRSAMC, Université P. Sabatier, 118 Route Narbonne, 31062 Toulouse, France.
Daudey
Jean-Pierre
JP
Maron
Laurent
L
Jolibois
Franck
F
D008956:Models, Chemical; D010070:Oxalates / Q000737:chemistry*; D011522:Protons; D011789:Quantum Theory; D013499:Surface Properties; D013816:Thermodynamics
D010070:Oxalates; D011522:Protons; C521322:monothiooxalic acid