Femtosecond dynamics of the ring closing process of diarylethene: A case study of electrocyclic reactions in photochromic single crystals

H Jean-Ruel, RR Cooney, M Gao, C Lu… - The Journal of …, 2011 - ACS Publications
H Jean-Ruel, RR Cooney, M Gao, C Lu, MA Kochman, CA Morrison, RJD Miller
The Journal of Physical Chemistry A, 2011ACS Publications
The cyclization reaction of the photochromic diarylethene derivative 1, 2-bis (2, 4-dimethyl-5-
phenyl-3-thienyl) perfluorocyclopentene was studied in its single crystal phase with
femtosecond transient absorption spectroscopy. The transient absorption measurements
were performed with a robust acquisition scheme that explicitly exploits the photoreversibility
of the molecular system and monitors the reversibility conditions. The crystalline system
demonstrated 3× 104 repeatable cycles before significant degradation was observed …
The cyclization reaction of the photochromic diarylethene derivative 1,2-bis(2,4-dimethyl-5-phenyl-3-thienyl)perfluorocyclopentene was studied in its single crystal phase with femtosecond transient absorption spectroscopy. The transient absorption measurements were performed with a robust acquisition scheme that explicitly exploits the photoreversibility of the molecular system and monitors the reversibility conditions. The crystalline system demonstrated 3 × 104 repeatable cycles before significant degradation was observed. Immediately following photoexcitation, the excited state absorption associated with the open-ring conformation undergoes a large spectral shift with a time constant of approximately 200 fs. Following this evolution on the excited state potential energy surface, the ring closure occurs with a time constant of 5.3 ps, which is significantly slower than previously reported measurements for similar derivatives in the solution phase. Time resolved electron diffraction studies were used to further demonstrate the assignment of the transient absorption dynamics to the ring closing reaction. The mechanistic details of the ring closing are discussed in the context of prior computational work along with a vibrational mode analysis using density functional theory to give some insight into the primary motions involved in the ring closing reaction.
ACS Publications
以上显示的是最相近的搜索结果。 查看全部搜索结果