Theoretical studies on the molecular structure, conformational preferences, topological and vibrational analysis of allicin

• Published in: Chemical physics letters 2016-01, Vol.644, p.5-13
• Main Authors: Durlak, Piotr, Berski, Sſawomir, Latajka, Zdzisſaw
• Format: Article
• Language: English
• Subjects: 2-Propene-1-sulphinothioic acid S-2-propenyl ester; Allicin; Car⿿Parrinello molecular dynamics (CPMD); Disulphide bond (bridge); Disulphides; Electron localization function (ELF); Garlic; Potential energy surface (PES)
• ISSN: 0009-2614; 1873-4448
• DOI: 10.1016/j.cplett.2015.11.038

⿢The weak hydrogen bond SO⿯H stabilizes the structure of allicin from the garlic (Allium sativum L.).⿢Car⿿Parrinello and path integrals molecular dynamics (CPMD/PIMD) of disulphide bond was performed.⿢In the course of the CPMD, even in PIMD simulations fast proton transfer (FPT) within the hydrogen bond was not observed.⿢The study of electronic structure of allicin that was performed in real space using topological analysis of electron localization function showed very similar nature of the SS and SO bonds. The molecular structure, conformational preferences, topological and vibrational analysis of allicin has been investigated at two different approaches. Calculations have been carried out on static (DFT and MP2) levels with an assortment of Dunning's basis sets and dynamic CPMD simulations. In this both case within the isolated molecule approximation. The results point out that at least twenty different conformers coexist on the PES as confirmed by the flexible character of this molecule. The topological analysis of ELF showed very similar nature of the SS and SO bonds. The infrared spectrum has been calculated, and a comparative vibrational analysis has been performed.