Intrinsic Structure and Electronic Spectrum of Deprotonated Biliverdin: Cryogenic Ion Spectroscopy and Ion Mobility
Intrinsic Structure and Electronic Spectrum of Deprotonated Biliverdin: Cryogenic Ion Spectroscopy and Ion Mobility
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去质子化胆绿素的本质结构和电子能谱：低温离子能谱和离子淌度
DOI：
10.1021/jacs.1c08701
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发表时间：
2021
影响因子：
15
通讯作者：
Weber, J. Mathias
中科院分区：
文献类型：
--
作者：
Zagorec-Marks, Wyatt;Dodson, Leah G.;Weis, Patrick;Schneider, Erik K.;Kappes, Manfred M.;Weber, J. Mathias
采用低温离子光谱、离子迁移率光谱和密度泛函理论相结合的方法研究了单去质子化胆绿素阴离子真空的结构和光谱性质。离子迁移率结果表明，至少存在两种构象，其中优势构象的相对丰度为75-90%。振动NH拉伸特征对四吡咯结构敏感，表明四吡咯体系为螺旋结构，与模拟离子迁移率碰撞截面一致。指纹区振动谱显示两个丙酸基团共享剩余的酸性质子。尽管在离子制备过程中离子阱温度为20k，但真空中的电子能谱s1波段仍然很宽，具有拥挤的frank - condon包膜，显示出部分分解的振动特征。垂直跃迁在水溶液中表现出较小的溶剂变色红移（−320 cm-1）。
We investigated the structural and spectroscopic properties of singly deprotonated biliverdin anionsin vacuo, using a combination of cryogenic ion spectroscopy, ion mobility spectrometry, and density functional theory. The ion mobility results show that at least two conformers are populated, with the dominant conformer at 75–90% relative abundance. The vibrational NH stretching signatures are sensitive to the tetrapyrrole structure, and they indicate that the tetrapyrrole system is in a helical conformation, consistent with simulated ion mobility collision cross sections. The vibrational spectrum in the fingerprint region of this singly deprotonated species shows that the two propionate groups share the remaining acidic proton. The S1band of the electronic spectrumin vacuois broad, despite ion trap temperatures of 20 K during ion preparation, with a congested Franck–Condon envelope showing partially resolved vibrational features. The vertical transition exhibits a small solvatochromic red shift (−320 cm–1) in aqueous solution.