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A REVERSIBLE PHOTOCHEMICAL REACTION OF CHLOROPHYLL a WITH I 2
Author(s) -
Livingston Robert,
Conrad J. R.
Publication year - 1969
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1969.tb05919.x
Subject(s) - photochemistry , methanol , absorption (acoustics) , chlorophyll a , chemistry , chlorophyll , analytical chemistry (journal) , optics , environmental chemistry , physics , organic chemistry , biochemistry
— Chlorophyll a and I 2 form a 1:1 addition compound, which exhibits a strong absorption maximum at about 360 nm. When dissolved in anaerobic methanol, this compound can be reversibly bleached by illumination with red light. Prolonged illumination at low temperatures (˜– 75°C) or intense illumination at room temperature reduces the height of the red absorp tion maximum to about half of its normal value. Since the thermal back reaction is negligibly slow at – 75°C, presumably the chlorophyll‐I 2 complex is converted completely to its bleached form, when illuminated under those conditions. This assumption leads to a simple mechanism which is consistent with the experimental data.