Department of Physics, Norwegian University of Science and Technology (NTNU), NO-7491 Trondheim, Norway.
J Photochem Photobiol B. 2012 Jan 5;106:34-9. doi: 10.1016/j.jphotobiol.2011.10.003. Epub 2011 Oct 19.
Though long-lived transient photoproducts of flavins have received much attention over the last five decades, their spectroscopic characterization remains rudimentary and altogether inconclusive. Lumiflavin and riboflavin have therefore been reexamined, using nanosecond laser photolysis and multichannel detection over a wide spectral range (230-900 nm); differential absorption spectra of flavin solutions in aqueous buffer at neutral pH have been recorded; radical cations and semiquinone radicals were generated by quenching the triplets with C (NO(2))(4) (electron acceptor) and NO(2)(-) (electron donor), respectively. The problem of estimating the extent of ground state depletion after a single flash has been solved by developing a new strategy that provides reliable lower and upper bounds for the depletion (and for the molar absorption coefficients of the transient species of interest). The spectra of the neutral radicals and triplets of the two flavins are almost identical, but those of the two cations are not.
尽管黄素类物质的长寿命瞬态光产物在过去五十年中受到了广泛关注，但它们的光谱特征仍然很基础，完全没有定论。因此，我们重新使用纳秒激光光解和多通道检测技术（波长范围 230-900nm），对光黄素和核黄素进行了重新检测；在中性 pH 值的水缓冲溶液中记录了黄素溶液的差示吸收光谱；分别用 C(NO2)4（电子受体）和 NO2-（电子供体）猝灭三重态，生成了自由基阳离子和半醌自由基。通过开发一种新策略，我们解决了在单次闪光后估计基态消耗程度的问题，该策略为消耗（以及感兴趣的瞬态物质的摩尔吸收系数）提供了可靠的下限和上限。两种黄素的中性自由基和三重态的光谱几乎相同，但两种阳离子的光谱则不同。
