CHEMISTRY VIA COMPUTATION “Applications on Molecular Nanoscience”, İstanbul, Türkiye, 30 Ekim 2018, ss.64
P37-Theoretical investigation of thiol-ene click reactions:a DFT perspective
Volkan Fındık1 İsa Değirmenci2 Şaron Çatak1 and Viktorya Aviyente1
1 Bogazici University, Faculty of Arts and Sciences, Department of Chemistry, 34342 Bebek, Istanbul, Turkey
2 Ondokuz Mayıs University, Chemical Engineering Department, 55139 Samsun, Turkey
In this study, for the first time a detailed study about the contribution of the phenyl thiol derivatives on the thiol-ene reaction mechanism has been carried out by using quantum chemical tools. DFT calculations have been used to investigate substitution effect on eleven thiol-ene reactions. It is well known that the reaction mechanism is strongly controlled by the kP/kCT ratio, where kP is the propagation rate constant of the thyl addition to the alkene and kCT is the rate constant of chain transfer to a thiol. All geometry optimizations and rate coefficients have been carried out with the M06-2X/6-31++G(d,p) methodology. The electrophilic nature of the phenylthio radicals and the S-T gap of the alkenes are mainly responsible for variation of the activation barriers of the propagation reaction, this demonstrates the importance of the ene functionality on the propagation reaction. The transition structures of the chain transfer reactions are stabilized by intramolecular interactions which lower the activation barriers. This study has revealed the fact that the kP/kCT ratio for the thiol-ene reactions does not only depend on the alkene functionality but on the thiol functionality as well, tailor-made polymers can be obtained by altering the substituents and the computational procedure described herein will guide the synthesis.
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