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Syntheses of Chalcone‐Type Chlorophyll Derivatives Possessing a Bacteriochlorin, Chlorin or Porphyrin π‐System and Their Optical Properties
Author(s) -
Ohashi Kota,
Kinoshita Yusuke,
Tamiaki Hitoshi
Publication year - 2018
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/php.13044
Subject(s) - chlorin , porphyrin , chalcone , chemistry , photochemistry , chlorophyll , chlorophyll a , organic chemistry , biochemistry
C3‐( Trans ‐2‐arylethenyl)carbonylated chlorophyll derivatives possessing a bacteriochlorin or chlorin π‐system were synthesized by cross‐aldol (Claisen–Schmidt) condensation of methyl pyrobacteriopheophorbide‐ a or 3‐acetyl‐3‐devinyl‐pyropheophorbide‐ a bearing the C3‐acetyl group with p ‐(un)substituted benzaldehydes under basic conditions. The corresponding porphyrin‐type chlorophyll derivatives were prepared by the oxidation (17,18‐didehydrogenation) of the chlorin‐type. Their Qy absorption and fluorescence emission maxima in dichloromethane correlated well with Hammett substituent constants of the p ‐substituents. Several electron‐withdrawing p‐ substituents suppressed the emission due to photoinduced electron transfer quenching in a molecule. The substitution sensitivities for their maxima and fluorescence quantum yields decreased in the order of bacteriochlorin‐, chlorin‐ and porphyrin‐type derivatives.