122nd General Meeting of the KCS

Type Oral Presentation
Area Oral Presentation for Young Scholars in Physical Chemistry
Room No. Room 324A
Time THU 09:36-:
Code PHYS.O-4
Subject Excited state intramolecular proton transfers and solvation dynamics probed by femtosecond stimulated Raman spectroscopy
Authors Myungsam Jen, Sebok Lee, Kooknam Jeon, Joonwoo Kim, Yoonsoo Pang*
Department of Chemistry, Gwangju Institute of Science and Technology, Korea
Abstract Proton transfer reactions are one of fundamental chemical reactions and have been of great interest in many disciplines including chemistry and biology. Excited state intramolecular proton transfer (ESIPT) of 1,2-dihydroxyanthraquinone (alizarin) and (1E,6E)-1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione (curcumin) between a hydroxyl and the adjacent carbonyl occurs on ultrafast time scales (<100 fs). Curcumin often forms a hydrogen bonding with solvents, where the deactivation occurs via the intermolecular hydrogen bonds between curcumin and solvents with decreasing the quantum yield. In this research, ultrafast chemical reactions of solute molecules in DMSO and subsequent solvent responses due to the solvation dynamics have been studied by femtosecond stimulated Raman spectroscopy. We have found that the (S=O) and (CSC) show a fast (<100 fs) increase especially at the frequencies for the aggregate (or dimer) form of DMSO molecules, and dissipates as the solute undergoes the vibrational relaxation along the potential energy surfaces of the reaction products. We try to convince that the solvent vibrational modes of DMSO can be utilized to monitor ultrafast chemical reactions of solute molecules, which can be widely applicable to the study of chemical reaction dynamics.
E-mail watqdt@gist.ac.kr