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OCTA‐ALKYL ZINC PHTHALOCYANINES: POTENTIAL PHOTOSENSITIZERS FOR USE IN THE PHOTODYNAMIC THERAPY OF CANCER
Author(s) -
Cook Michael J.,
Chambrier Isabelle,
Cracknell Steven J.,
Mayes Denise A.,
Russell David A.
Publication year - 1995
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.1751-1097.1995.tb02381.x
Subject(s) - chemistry , singlet oxygen , photodynamic therapy , phthalocyanine , photochemistry , cyclohexane , zinc , alkyl , derivative (finance) , fluorescence , porphyrin , photosensitizer , absorbance , rose bengal , organic chemistry , oxygen , financial economics , economics , physics , chromatography , quantum mechanics
— The synthesis, characterization and electronic spectra of a series of nine 1,4,8,11,15,18,22,25‐octa‐alkyl zinc phthalocyanines (ZnPc), potential photosensitizers for the photodynamic therapy of cancer, are described. The substituents on the phthalocyanine (Pc) macrocycle “red‐shift” the absorbance maximum, in cyclohexane, of all nine members of this series to a value of 703 ± 2 nm, with a corrected fluorescence emission maximum for the octadecyl derivative of 715 nm. The solubilities and degree of aggregation of six examples in cyclohexane have been measured. The highest homologue, the octadecyl derivative, remains essentially unaggregated to a concentration of 1.5 ± 10 −4 mol dm −3 . The photostability of this Pc has been examined and the compound shown to be sensitive to photooxidation processes, which lead to its decomposition to 3,6‐fcw‐decylphthalimide. Known singlet oxygen quenchers inhibit the photodecomposition. In a comparative study, the octadecyl ZnPc underwent a more rapid photodecomposition than the corresponding metal‐free derivative.