title: Active role of proton in excited state intramolecular proton transfer reaction.
abstract: Proton transfer is one of the most important elementary reactions in chemistry and biology. The role of proton in the course of proton transfer, whether it is active or passive, has been the subject of intense investigations. Here we demonstrate the active role of proton in the excited state intramolecular proton transfer (ESIPT) of 10-hydroxybenzo[h]quinoline (HBQ). The ESIPT of HBQ proceeds in 12 ± 6 fs, and the rate is slowed down to 25 ± 5 fs for DBQ where the reactive hydrogen is replaced by deuterium. The results are consistent with the ballistic proton wave packet transfer within the experimental uncertainty. This ultrafast proton transfer leads to the coherent excitation of the vibrational modes of the product state. In contrast, ESIPT of 2-(2'-hydroxyphenyl)benzothiazole (HBT) is much slower at 62 fs and shows no isotope dependence implying complete passive role of the proton.
authors: Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang, 790-784, South Korea.
authors: Junghwa
authors: J
authors: Lee
authors: Chul Hoon
authors: CH
authors: Kim
authors: Taiha
authors: T
authors: Joo
mesh_terms: D052160:Benzothiazoles / Q000737:chemistry*; D015394:Molecular Structure; D010636:Phenols / Q000737:chemistry*; D011522:Protons; D011804:Quinolines / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: C521323:10-hydroxybenzo(h)quinoline; D052160:Benzothiazoles; D010636:Phenols; D011522:Protons; D011804:Quinolines; C070846:2-(2-hydroxyphenyl)benzothiazole