Spectroscopic Analysis of a Biomimetic Model of TyrZ Function in PSII
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- 作者：Janneke Ravensbergen ; Antaeres Antoniuk-Pablant ; Benjamin D. Sherman ; Gerdenis Kodis ; Jackson D. Megiatto ; Jr. ; Dalvin D. M茅ndez-Hern谩ndez ; Raoul N. Frese ; Rienk van Grondelle ; Thomas A. Moore ; Ana L. Moore ; Devens Gust ; John T. M. Kennis
- 刊名：Journal of Physical Chemistry B
- 出版年：2015
- 出版时间：September 17, 2015
- 年：2015
- 卷：119
- 期：37
- 页码：12156-12163
- 全文大小：367K
- ISSN：1520-5207
文摘
Using natural photosynthesis as a model, bio-inspired constructs for fuel generation from sunlight are being developed. Here we report the synthesis and time-resolved spectroscopic analysis of a molecular triad in which a porphyrin electron donor is covalently linked to both a cyanoporphyrin electron acceptor and a benzimidazole鈥損henol model for the TyrZ-D1His190 pair of PSII. A dual-laser setup enabled us to record the ultrafast kinetics and long-living species in a single experiment. From this data, the photophysical relaxation pathways were elucidated for the triad and reference compounds. For the triad, quenching of the cyanoporphyrin singlet excited state lifetime was interpreted as photoinduced electron transfer from the porphyrin to the excited cyanoporphyrin. In contrast to a previous study of a related molecule, we were unable to observe subsequent formation of a long-lived charge separated state involving the benzimidazole鈥損henol moiety. The lack of detection of a long-lived charge separated state is attributed to a change in energetic landscape for charge separation/recombination due to small differences in structure and solvation of the new triad.