The Impact of the 515nm Effect on Singlet Oxygen Quenching in Photosynthesis:  Model System Studies Using β –Carotene–Acid Complexes

Title

The Impact of the 515nm Effect on Singlet Oxygen Quenching in Photosynthesis: Model System Studies Using β –Carotene–Acid Complexes

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Description

β-carotene (βC) is an orange biological pigment present in green plants, where it plays a protective role against the potential harmful effects of light. βC does this by deactivating “singlet oxygen”, which is a toxic molecule generated during photosynthesis. During photosynthesis, βC temporarily converts from its native orange state to a pink state. We hypothesized that pink βC reacts with singlet oxygen less efficiently than native orange βC. To test this hypothesis, we chemically modeled βC’s pink state with blue βC–acid complexes, which are chemically similar to pink βC, created by reacting βC with trichloroacetic acid (TCA). βC’s efficiency at deactivating singlet oxygen was characterized by measuring the rate of degradation of 1,3-diphenylisobenzofuran (DPBF), which has a high reactivity towards singlet oxygen and is used to detect the amount of singlet oxygen in a solution. Our DPBF–based results to date indicate that native orange βC and blue βC–TCA complexes quench singlet oxygen with roughly equal efficiency. In future studies, we intend to confirm our DPBF–based results by monitoring the impact of βC and βC–TCA complexes on the 1270 nm (near–infrared) emission of singlet oxygen using a state–of–the–art, time–resolved near–infrared spectrometer; the UD Chemistry Department hopes to purchase this instrument in the near future. The results from this research could facilitate the development of solar energy devices with greater long-term stability.

Publication Date

4-18-2018

Project Designation

Honors Thesis

Primary Advisor

Mark B Masthay

Primary Advisor's Department

Chemistry

Keywords

Stander Symposium poster

Comments

Presenters: Lauren Arlene Hoody, Caoqinglong Huang, Ashlee Elizabeth Wertz

The Impact of the 515nm Effect on Singlet Oxygen Quenching in Photosynthesis:  Model System Studies Using β –Carotene–Acid Complexes

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