Ultrafast Circular Dichroism Study of the Ring Opening of 7-Dehydrocholesterol
Ultrafast Circular Dichroism Study of the Ring Opening of 7-Dehydrocholesterol
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DOI：
10.1021/jz2014659
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发表时间：
2012-01-19
影响因子：
5.7
通讯作者：
Dietzek, Benjamin
中科院分区：
文献类型：
--
作者：
Meyer-Ilse, Julia;Akimov, Denis;Dietzek, Benjamin
利用紫外飞秒时间分辨圆二色光谱（TRCD）研究了小分子生物样品7-脱氢胆固醇（7-DHC）的超快手性变化。在UV光激发下，7-DHC经历开环以产生前维生素D-3，并且7-DHC的两个手性中心被去除，这影响分子的整体手性。在这里，测量连接到开环的7-DHC的280 fs的时间分辨率在UV的手性变化的报告。用这种方法，澄清了先前描述的关于7-DHC的物理性质的差异。通过我们的设置，测得手性变化的弛豫时间为1-2 ps，这对应于瞬态吸收（TA）测量中的最短时间常数，使我们能够将该时间常数分配给开环。
UV femtosecond time-resolved circular dichroism (TRCD) spectroscopy has been used to study the ultrafast changes of chirality in a small molecular biological paradigm sample, 7-dehydrocholesterol (7-DHC). Upon UV-photoexcitation, 7-DHC undergoes a ring opening to produce previtamin D-3, and two of the chiral centers of 7-DHC are removed, which impacts the overall chirality of the molecule. Here, measurements of this chirality change connected to the ring opening of 7-DHC with a time resolution of 280 fs in the UV are reported. With this method, a previously described discrepancy concerning the photophysics of 7-DHC was clarified. With our setup, the relaxation time of the chirality change was measured to be 1-2 ps, which corresponds to the shortest time constant in the transient absorption (TA) measurements, allowing us to assign that time constant to the ring opening.