Three Dimensional Triply Resonant Sum Frequency Spectroscopy Revealing Vibronic Coupling in Cobalamins: Toward a Probe of Reaction Coordinates
Three Dimensional Triply Resonant Sum Frequency Spectroscopy Revealing Vibronic Coupling in Cobalamins: Toward a Probe of Reaction Coordinates
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三维三重共振和频谱揭示钴胺素中的振动耦合：探索反应坐标
DOI：
10.1021/acs.jpca.8b07678
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
Wright, John C.
中科院分区：
文献类型：
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作者：
Handali, Jonathan D.;Sunden, Kyle F.;Thompson, Blaise J.;Neff-Mallon, Nathan A.;Kaufman, Emily M.;Brunold, Thomas C.;Wright, John C.
三共振和频率（TRSF）光谱是一种完全相干的混合振动电子光谱技术，非常适合探测在驱动反应中变得重要的振动电子耦合。我们已经使用氰钴胺素（CNCbl）和氘化水产养殖钴胺素（d20ocbl +）作为模型系统，以证明使用相干多维光谱的选择性来解决过渡金属配合物的宽吸收光谱中的电子状态，并确定振动和电子状态耦合的性质的可行性。我们在振动拥挤的1400-1750 cm - 1区域解决了三种短轴和长轴振动模式，它们分别耦合到18 000 - 21 000 cm - 1区域的不同电子态，但彼此之间的耦合最小。具有单个振动基元及其泛音的双共振选择性地增强了相应的电子共振，并在广泛的吸收光谱内解决了特征。这项工作证明了识别不同电子态对的振动态之间耦合的可行性，这些振动态对共同形成过渡金属酶的反应配位面。
Triply resonant sum frequency (TRSF) spectroscopy is a fully coherent mixed vibrational–electronic spectroscopic technique that is ideally suited for probing the vibrational–electronic couplings that become important in driving reactions. We have used cyanocobalamin (CNCbl) and deuterated aquacobalamin (D2OCbl+) as model systems for demonstrating the feasibility of using the selectivity of coherent multidimensional spectroscopy to resolve electronic states within the broad absorption spectra of transition metal complexes and identify the nature of the vibrational and electronic state couplings. We resolve three short and long axis vibrational modes in the vibrationally congested 1400–1750 cm–1region that are individually coupled to different electronic states in the 18 000–21 000 cm–1region but have minimal coupling to each other. Double resonance with the individual vibrational fundamentals and their overtones selectively enhances the corresponding electronic resonances and resolves features within the broad absorption spectrum. This work demonstrates the feasibility of identifying coupling between different pairs of vibrational states with different electronic states that together form the reaction coordinate surface of transition metal enzymes.