Observation of the Ring-Puckering Vibrational Mode in Thietane Cation

조회수 : 97 등록일 : 2017.04.26 00:00

저자 : Sung, BJ (Sung, Bong June)
출판일 : 2017.02.09
Observation of the Ring-Puckering Vibrational Mode in Thietane Cation
Lee, YR (Lee, Yu Ran)[ 1,2 ] ; Park, CB (Park, Chung Bin)[ 3 ] ; Hwang, J (Hwang, Jiye)[ 3 ] ; Sung, BJ (Sung, Bong June)[ 3 ] ; Kim, HL (Kim, Hong Lae)[ 1,2 ] ; Kwon, CH (Kwon, Chan Ho)[ 1,2 ]
[ 1 ] Kangwon Natl Univ, Dept Chem, Chunchon 24341, South Korea
[ 2 ] Kangwon Natl Univ, Inst Mol Sci & Fus Technol, Chunchon 24341, South Korea
[ 3 ] Sogang Univ, Dept Chem, Seoul 04107, South Korea
We have measured the high-resolution vibrational spectra of a thietane (trimethylene sulfide) cation in the gas phase by employing the vacuum ultraviolet mass analyzed threshold ionization (VUV-MATI) spectroscopic technique. Peaks in the low frequency region of the observed MATI spectrum of thietane originate from a progression of the ring-puckering vibrational mode (typical in small heterocyclic molecules), which is successfully reproduced by quantum-chemical calculations with 1D symmetric double-well potentials along the ring puckering coordinates on both the S-0 and D-0 states, the ground electronic states of neutral and cation of thietane, respectively. The values of the interconversion barrier and the ring-puckering angle on the S-0 state, the parameters used for the quantum-chemical calculations, were assumed to be 274 cm(-1) and 26 degrees. The barrier and the angle on the D-0 state, however, are found to be 48.0 cm(-1) and 18.2 degrees, respectively, where such small barrier height and puckering angle for the cation suggest that the conformation of thietane cation on the D-0 state should be more planar-than that of the thietane neutral.
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