Pronounced Tunneling Effect of Proton Transfer in Thiotropolone at Room Temperature: A Reply

摘要

In a recent comment on our Communication Antonio Fernandez-Ramos has criticized our work suggesting that tunneling effects are not important on thiotropolone (1 in our original Communication; see Scheme 1). His argument being basically that since the process of proton transfer process from the thione (la) to the enethiol (lb) is endoergic, at low temperatures, the molecules just do not have enough energy to tunnel from one valley to another valley. This is certainly true at very low (T of about 0 K) temperatures. However, even at cryogenic temperatures and certainly at room temperature, few molecules will be vibrationally excited to be able to cross to other valleys through tunneling. We agree that the potential-energy surfaces are different for thiotropolone (1) and tropolone (3). Therefore, we would like to point out that there is no disagreement with the pronounced tunneling effect of proton transfer in tropolone (3) and in both articles similar results are found. We also agree that the conventional way of calculating the transmission coefficient (as an integral) is not appropriate (footnote of Table S3 in the Supporting Information in Antonio Fernandez-Ramos's article) for endoergic reactions. Therefore, the formula being suggested by Fernandez-Ramos should be used instead.