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

作者：Buckup Tiago; Sarter Christopher; Volpp Hans Robert; Jaeschke Andres; Motzkus Marcus^*

来源：Journal of Physical Chemistry Letters, 2015, 6(23): 4717-4721.

DOI：10.1021/acs.jpclett.5b01949

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 femto-second 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 Is toward the S-1/S-0 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, Phi(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).

• 出版日期2015-12-3