Ultrafast Time-Resolved Spectroscopy of Diarylethene-Based Photoswitchable Deoxyuridine Nucleosides

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• 作者：Tiago Buckup ; Christopher Sarter ; Hans-Robert Volpp ; Andres J盲schke ; Marcus Motzkus
• 刊名：The Journal of Physical Chemistry Letters
• 出版年：2015
• 出版时间：December 3, 2015
• 年：2015
• 卷：6
• 期：23
• 页码：4717-4721
• 全文大小：327K
• ISSN：1948-7185

文摘

Photoswitches based on the diarylethene architecture have been attracting considerable attention for the investigation and control of a variety of biological processes. The reversible photoisomerization reaction between their open- and closed-ring forms can be selectively addressed by irradiation with light of two markedly different wavelengths. In this work, the dynamics of the photochromic ring-opening reaction of four novel diarylethene-based photoswitchable deoxyuridine nucleosides is investigated by femtosecond transient absorption. Upon photoexcitation with sub-20 fs pulses in the first absorption band (500 nm), all four photoswitches showed a fast ballistic excited-state deactivation within less than 500 fs toward the S₁/S₀ conical intersection. Transient data was globally analyzed, and a relaxation kinetic model with a branching between open and closed ring forms without any loss channels was derived. Ring-opening quantum yields, 桅_r-o, were found to strongly depend on the substituents (R), ranging from 0.64 (dU^PSI: R = 2-naphthyl) to 0.30 (dU^PSIV: R = 2-pyridyl).