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Self‐aggregation of Synthetic Protobacteriochlorophyll‐ d Derivatives ¶
Author(s) -
Tamiaki Hitoshi,
Kitamoto Hiroyuki,
Watanabe Takuya,
Shibata Reiko
Publication year - 2005
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.1751-1097.2005.tb01537.x
Subject(s) - bacteriochlorophyll , chromophore , chemistry , porphyrin , chlorin , zinc , photochemistry , moiety , supramolecular chemistry , chlorosome , cyclohexane , circular dichroism , pigment , tetrahydrofuran , stereochemistry , molecule , organic chemistry , solvent
ABSTRACT 3 1 ‐Racemically pure zinc 3 1 ‐hydroxy‐13 1 ‐oxo‐porphyrins (zinc methyl 17,18‐dehydro‐bacteriopheophorbides‐ d ) as well as their 3 1 ‐demethyl form were prepared by modifying chlorophyll‐ a through oxidation by 2,3‐dichloro‐5,6‐dicyano‐benzoquinone. From visible, circular dichroism and infrared spectral analyses, these synthetic pigments self‐aggregated in 1%(vol/vol) tetrahydrofuran and cyclohexane to give large oligomers by an intermolecular bonding of 13‐C=O…H‐O(3 1 ) … Zn(central) and π‐π interaction of the porphyrin chromophores. The supramolecular structures are similar to those of the corresponding chlorins and a core part of extra‐membranous light‐harvesting antennas of photosynthetic green bacteria. The 17,18‐dehydrogenation of a chlorin to porphyrin moiety did not disturb its self‐aggregation, and the synthetic zinc porphyrins are good models for naturally occurring, self‐aggregative bacteriochlorophylls.