Estudo quântico computacional da reação de dissociação do hidrogênio na ligação S-H em tiofenóis clorados

Abstract

In this work calculations were performed of Density Functional Theory with the functional wB97XD, TPSSh, B3LYP, M062X and M11. The basis functions sets 6-31+G(d,p), 6-311++G(d,p), cc-pVDZ, aug-cc-pVDZ and aug-cc-pVTZ were used to evaluate the variation of the enthalpy of hydrogen dissociation reaction at S-H bond in systems ortho-chloro-thiophenol, meta-chloro-thiophenol and para-chloro-thiophenol. To describe the dissociation reaction was taken into account the change of spin state throughout the reaction making use of the potential energy surface in the singlet and triplet state. The results showed that the M11/6-31+G(d,p) method may be suitable for describing and predicting cross-system intersection, as well as a good description of the enthalpy change of the reaction. The difference of spin density in the dissociation reaction pathway in the study was calculated, where it was perceived that the excess alpha spin density is located in the hydrogen atom and in the sulfur atom, thus the nature of the ortho-chloro-thiophenol radical in the reaction product was revealed.