Circular Dichroism Spectroscopy of Cold Molecules and Clusters in the Isolated Gas Phase

Speaker: 김남준 교수(충북대)

Date & Time: 2019. 11. 27. 수요일 17:00

Where: 융대원 D-122호

Abstract

Circular dichroism (CD) spectra measured in solution represent only the average CD values of all conformational isomers. In contrast, the CD spectroscopy of jet-cooled chiral molecules in the gas phase can provide conformation-selective CD values without influence of solvent molecules. We developed a new CD spectroscopic technique that could be used to obtain the resonant two-photon CD spectra of jet-cooled molecules. Using this CD technique, we investigated the induced circular dichroism (ICD) of jet-cooled phenol complexes with (–)-methyl L-lactate (PhOH-(–)ML). CD is generally observed for chiral molecules. However, achiral molecules can have CD when they are bound with a chiral molecule through noncovalent interactions, which is denoted as ICD. ICD has been employed to investigate the structures and binding properties of various host-guest complexes. Here, we obtained the first isomer-selective ICD spectra of jet-cooled PhOH-(–)ML. The ICD values of the two conformers have different signs and magnitudes, which were explained by differences both in the geometrical asymmetries of PhOH bound to (–)ML and in the electronic coupling strengths between PhOH and (–)ML. The ICD spectra of phenol complexes with R-(–)-2-butanol and R-(–)-1-amino-2-propanol were also obtained to investigate the physical properties that might govern the differences of the ICD values between the two complexes.

Biography

[학력]

Ph.D Chemistry, Seoul National University, Seoul, Korea [2000]

M.S. Chemistry, Seoul National University, Seoul, Korea [1994]

B.S. Chemistry, Seoul National University, Seoul, Korea [1992]

 

[경력]

Professor, Department of Chemistry, Chungbuk National University [2003. 3 – present]

Post-doctoral scholar, Division of Chemistry and Chemical Engineering, California Institute of Technology [2000. 10 – 2003. 2]

 

초청자 : 융합과학부 나노융합전공 김창순 교수(changsoon@snu.ac.kr)

2019-11-24|