Ultrafast Excited State Dynamics and Fluorescence from Vitamin B 12 and Organometallic [Co]–C≡C–R Cobalamins
Ultrafast Excited State Dynamics and Fluorescence from Vitamin B 12 and Organometallic [Co]–C≡C–R Cobalamins
复制标题
维生素 B 12 和有机金属 [Co]–C–C–R 钴胺素的超快激发态动力学和荧光
DOI：
10.1021/acs.jpcb.0c04886
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Sension, Roseanne J.
中科院分区：
文献类型：
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作者：
Salerno, Elvin V.;Miller, Nicholas A.;Konar, Arkaprabha;Li, Yan;Kieninger, Christoph;Kräutler, Bernhard;Sension, Roseanne J.
钴胺素是以钴为中心的环状四吡咯环分子，为特殊的生物过程提供辅助因子，并具有独特的合成可调光化学。典型的钴胺素的特征在于由标记为 α、β 和 sh 的峰组成的可见吸收光谱。尽管进行了大量研究，但这些峰作为电子起源或电子振动级数的物理基础仍然不明确。在这里，首次在几种衍生物中鉴定出钴胺素荧光。荧光寿命约为。由于“暗”激发态的快速增长，量子产率约为 100–200 fs，量子产率约为 10–6–10–5。将结果与用锌取代咕啉环中的钴的荧光类似物进行比较。对发射光谱宽度的分析提供了证据，表明单激发电子态的振动进展对可见光吸收带做出了主要贡献。
Cobalamins are cobalt-centered cyclic tetrapyrrole ring-based molecules that provide cofactors for exceptional biological processes and possess unique and synthetically tunable photochemistry. Typical cobalamins are characterized by a visible absorption spectrum consisting of peaks labeled α, β, and sh. The physical basis of these peaks as having electronic origin or as a vibronic progression is ambiguous despite much investigation. Here, for the first time, cobalamin fluorescence is identified in several derivatives. The fluorescence lifetime is ca. 100–200 fs with quantum yields on the order of 10–6–10–5because of rapid population of “dark” excited states. The results are compared with the fluorescent analogue with zinc replacing the cobalt in the corrin ring. Analysis of the breadth of the emission spectrum provides evidence that a vibrational progression in a single excited electronic state makes the dominant contribution to the visible absorption band.