Photophysical properties of structurally and electronically modified flavin derivatives determined by spectroscopy and theoretical calculations.
Photophysical properties of structurally and electronically modified flavin derivatives determined by spectroscopy and theoretical calculations.
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通过光谱学和理论计算确定结构和电子改性黄素衍生物的光物理性质。
DOI：
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发表时间：
2009
影响因子：
2.9
通讯作者：
W. Gärtner
中科院分区：
文献类型：
--
作者：
Susanne Salzmann;Víctor Martínez;B. Zorn;S. Braslavsky;Madina Mansurova;C. Marian;W. Gärtner
四种不同的核黄素（RF）衍生物，两个电子修饰的化合物（1-和5-deazariboflavin，1DRF和5DRF）和两个空间修饰的化合物（7，8-二甲基-和8-异丙基核黄素，DMRF和iprRF），进行了时间分辨测量（吸收和荧光）和高层次的量子化学研究的组合。两种烷基修饰的黄素显示出与母体化合物相似的荧光性质，但5DRF具有比RF（PhiF = 0.27）更大的荧光量子产率（PhiF = 0.52）。有趣的是，1DRF在这些稳态条件下根本不显示荧光。三重态量子产率对于修饰的黄素是不同的，使得对于1DRF没有发现三重态形成，而其它化合物全部形成三重态（对于5DRF的PhiTR分别为0.64，对于iprRF和DMRF的PhiTR分别为0.50和0.23）。这两种烷基修饰的黄素的三重态以与母体化合物相似的时间常数衰变，而5DRF的寿命较短（tauTR = 15 μ s，而RF的tauTR = 29 μ s）。在计算中，黄素衍生物被建模为光黄素，即没有核糖基链。我们的结论是，DMRF，iprRF，和5DRF的水溶液的系间穿越（ISC）发生从S1 1（pipi*）的T2 3（pipi*）状态的振动自旋轨道耦合机制，一个过程中常见的大多数黄素，而ISC是缓慢的激发1DRF由于没有一个接近的三重态。
Four different riboflavin (RF) derivatives, two electronically modified compounds (1- and 5-deazariboflavin, 1DRF and 5DRF) and two sterically modified compounds (7,8-didemethyl- and 8-isopropylriboflavin, DMRF and iprRF), were subjected to a combination of time-resolved measurements (absorption and fluorescence) and high-level quantum chemical investigations. Both alkyl-modified flavins showed similar fluorescence properties as the parent compound, yet 5DRF had a larger quantum yield of fluorescence (PhiF = 0.52) than RF (PhiF = 0.27). Interestingly, 1DRF did not show fluorescence at all under these steady state conditions. The triplet quantum yield was different for the modified flavins such that no triplet formation was found for 1DRF, whereas the other compounds all formed triplet states (PhiTR for 5DRF of 0.64 and 0.50 and 0.23 for iprRF and DMRF, respectively). The triplet states of the two alkyl-modified flavins decayed with similar time constants as the parent compound, whereas a shorter lifetime was measured for 5DRF (tauTR = 15 micros, compared to tauTR = 29 micros for RF). In the calculations, the flavin derivatives were modeled as lumiflavins, that is, without the ribityl chain. We conclude that for aqueous solutions of DMRF, iprRF, and 5DRF intersystem crossing (ISC) takes place from the S1 1(pipi*) to the T2 3(pipi*) state by a vibronic spin-orbit coupling mechanism, a process common to most flavins, whereas ISC is slow in excited 1DRF due to the absence of a close-by triplet state.
影响因子：
3.4
作者：
Domratcheva, Tatiana;Grigorenko, Bella L.;Nemukhin, Alexander V.
通讯作者：
Nemukhin, Alexander V.
影响因子：
2.9
作者：
Kennis, JTM;Crosson, S;van Grondelle, R
通讯作者：
van Grondelle, R