Effect of alkali ions on optical properties of flavins: vibronic spectra of cryogenic M+lumiflavin complexes (M = Li-Cs).
Effect of alkali ions on optical properties of flavins: vibronic spectra of cryogenic M+lumiflavin complexes (M = Li-Cs).
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碱离子对黄素光学性质的影响：低温 M 发光黄素复合物的振动光谱（M = Li-Cs）
DOI：
10.1039/c8fd00203g
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发表时间：
2019
影响因子：
3.4
通讯作者：
O. Dopfer
中科院分区：
文献类型：
--
作者：
D. Müller;P. Nieto;M. Miyazaki;O. Dopfer
黄素类化合物由于其独特的光学性质而经常被自然界用于光化学过程中，这种性质可以受到周围环境的强烈调制，如溶剂化作用或与金属离子的配位作用。在这里，我们利用黄素家族的母体分子光黄素(Lf，C13H12N4O2)和碱性离子(M=Li-Cs)组成的低温M+LF络合物的振动光解离光谱来表征金属化对LF发色团电子性质的强烈影响。借助于含时密度泛函理论计算(PbE0/cc-pVDZ)和多维Franck-Condon模拟，将记录在5 0 0-5 70 nm范围内的M+Lf离子的可见光解离谱归属于最低能量M+Lf(O4+)异构体的S1←S0(ππ*)跃迁到第一个光学明亮的S1态.在这种O4+结构中，M+以弯曲的络合物与Lf的O4和N5原子的孤对结合。S_1激发引起的电荷重组强烈地增强了M+与L F在该结合部位的相互作用，导致S_1吸收红移约10-20%(例如，从L F的465 nm红移到Li+L F的567 nm)。M+⋯Lf(O4+)中M+ππLf相互作用强度的这种强烈变化可以用参与S1←S0跃迁的轨道来解释，并引起强烈的振动活性。特别是，分子间弯曲和拉伸模式的进展提供了M+⋯LF键强度的准确测量。与实验确定的O4+离子相反，预测的其他低能M+LF异构体O2+和O2的S1起源与LF的S1略有蓝移，表明金属化LF的电子性质不仅随金属离子的大小而变化，而且随其结合位置的变化而变化。
Flavin compounds are frequently used by nature in photochemical processes because of their unique optical properties which can be strongly modulated by the surrounding environment such as solvation or coordination with metal ions. Herein, we employ vibronic photodissociation spectroscopy of cryogenic M+LF complexes composed of lumiflavin (LF, C13H12N4O2), the parent molecule of the flavin family, and alkali ions (M = Li–Cs) to characterize the strong impact of metalation on the electronic properties of the LF chromophore. With the aid of time-dependent density functional theory calculations (PBE0/cc-pVDZ) coupled to multidimensional Franck–Condon simulations, the visible photodissociation (VISPD) spectra of M+LF ions recorded in the 500–570 nm range are assigned to the S1 ← S0 (ππ*) transitions into the first optically bright S1 state of the lowest-energy M+LF(O4+) isomers. In this O4+ structure, M+ binds in a bent chelate to the lone pairs of both the O4 and the N5 atom of LF. Charge reorganization induced by S1 excitation strongly enhances the interaction between M+ and LF at this binding site, leading to substantial red shifts in the S1 absorption of the order of 10–20% (e.g., from 465 nm in LF to 567 nm in Li+LF). This strong change in M+⋯LF interaction strength in M+LF(O4+) upon ππ* excitation can be rationalized by the orbitals involved in the S1 ← S0 transition and causes strong vibrational activity. In particular, progressions in the intermolecular bending and stretching modes provide an accurate measure of the strength of the M+⋯LF bond. In contrast to the experimentally identified O4+ ions, the predicted S1 origins of other low-energy M+LF isomers, O2+ and O2, are slightly blue-shifted from the S1 of LF, demonstrating that the electronic properties of metalated LF not only drastically change with the size of the metal ion but also with its binding site.
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DOI：
10.1039/c8cp05368e
发表时间：
2018
期刊：
Physical chemistry chemical physics : PCCP
影响因子：
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作者：
K. Lincke;J. Langeland;A. Ø. Madsen;H. V. Kiefer;L. Skov;E. Gruber;K. Mikkelsen;L. H. Andersen;M. Nielsen
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发表时间：
1961-01-01
期刊：
BIOCHIMICA ET BIOPHYSICA ACTA
影响因子：
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BAARDA, IF;METZLER, DE
通讯作者：
METZLER, DE
DOI：
10.1039/c4cp01524j
发表时间：
2014-06
期刊：
Physical chemistry chemical physics : PCCP
影响因子：
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作者：
A. Günther;P. Nieto;G. Berden;J. Oomens;O. Dopfer
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A. Günther;P. Nieto;G. Berden;J. Oomens;O. Dopfer
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影响因子：
4.4
作者：
L. Giacomozzi;Christina Kjær;J. L. Knudsen;Lars H. Andersen;S. B. Nielsen;M. Stockett
通讯作者：
M. Stockett