Jiyeon Yun, Changseop Jeong, Jiyoung Heo, Nam Joon Kim
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引用次数: 0
Abstract
Vibrational mode-dependent circular dichroism (CD) effects in vibrational CD spectra are often used to determine the handedness of molecules with multiple chiral centers. Here, we investigate vibrational mode-dependent CD effects in the electronic CD spectra of jet-cooled (R)–(+)– and (S)–(−)–styrene oxide obtained by using resonant two-photon ionization CD (R2PICD) spectroscopy. Although most fundamental vibronic bands demonstrated CD signatures consistent with that of the origin band, the overtone and combination bands exhibited opposite CD signatures. Theoretical calculations suggest that CD in fundamental bands are primarily governed by Franck–Condon contributions, whereas Herzberg–Teller contributions, which reflect the influences of vibrational modes on CD values, become more significant in overtone and combination bands. These results underscore the potential of mode-dependent vibronic CD signals in R2PICD spectra for determining the absolute configurations of molecules with multiple chiral centers.
振动 CD 光谱中的振动模式依赖性圆二色性(CD)效应通常用于确定具有多个手性中心的分子的手性。在此,我们利用共振双光子电离 CD(R2PICD)光谱法研究了喷射冷却的(R)-(+)-和(S)-(-)-氧化苯乙烯电子 CD 光谱中的振动模式依赖性 CD 效应。虽然大多数基本振动带显示出与原点带一致的 CD 特征,但泛音带和组合带却显示出相反的 CD 特征。理论计算表明,基带的 CD 主要受弗兰克-康顿贡献的影响,而赫茨伯格-泰勒贡献(反映振动模式对 CD 值的影响)在泛音和组合带中变得更为重要。这些结果凸显了 R2PICD 光谱中依赖于振动模式的振动 CD 信号在确定具有多个手性中心的分子的绝对构型方面的潜力。
期刊介绍:
The Journal of Physical Chemistry (JPC) Letters is devoted to reporting new and original experimental and theoretical basic research of interest to physical chemists, biophysical chemists, chemical physicists, physicists, material scientists, and engineers. An important criterion for acceptance is that the paper reports a significant scientific advance and/or physical insight such that rapid publication is essential. Two issues of JPC Letters are published each month.