The reaction rate of a catalyzed reaction is faster than the reaction rate of the uncatalyzed reaction at the same temperature.14187-32-7, Name is Dibenzo-18-crown-6, molecular formula is C20H24O6. In a Article£¬once mentioned of 14187-32-7, Recommanded Product: 14187-32-7
Microhydration effects on the encapsulation of potassium ion by dibenzo-18-crown-6
We have measured electronic and conformer-specific vibrational spectra of hydrated dibenzo-18-crown-6 (DB18C6) complexes with potassium ion, K +?DB18C6?(H2O)n (n = 1-5), in a cold, 22-pole ion trap. We also present for comparison spectra of Rb +?DB18C6?(H2O)3 and Cs +?DB18C6?(H2O)3 complexes. We determine the number and the structure of conformers by analyzing the spectra with the aid of quantum chemical calculations. The K +?DB18C6?(H2O)1 complex has only one conformer under the conditions of our experiment. For K +?DB18C6?(H2O)n with n = 2 and 3, there are at least two conformers even under the cold conditions, whereas Rb+?DB18C6?(H2O)3 and Cs +?DB18C6?(H2O)3 each exhibit only one isomer. The difference can be explained by the optimum matching in size between the K+ ion and the crown cavity; because the K+ ion can be deeply encapsulated by DB18C6 and the interaction between the K+ ion and the H2O molecules becomes weak, different kinds of hydration geometries can occur for the K+?DB18C6 complex, giving multiple conformations in the experiment. For K+?DB18C6?(H 2O)n (n = 4 and 5) complexes, only a single isomer is found. This is attributed to a cooperative effect of the H2O molecules on the hydration of K+?DB18C6; the H2O molecules form a ring, which is bound on top of the K+?DB18C6 complex. According to the stable structure determined in this study, the K + ion in the K+?DB18C6?(H2O) n complexes tends to be pulled largely out from the crown cavity by the H2O molecules with increasing n. Multiple conformations observed for the K+ complexes will have an advantage for the effective capture of the K+ ion over the other alkali metal ions by DB18C6 because of entropic effects on the formation of hydrated complexes.
The reactant in an enzyme-catalyzed reaction is called a substrate. Enzyme inhibitors cause a decrease in the reaction rate of an enzyme-catalyzed reaction.I hope my blog about 14187-32-7 is helpful to your research., Recommanded Product: 14187-32-7
Reference£º
Chiral Catalysts,
Chiral catalysts – SlideShare