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CARBOXYLATED ZINC‐PHTHALOCYANINES–II * DIMERIZATION AND SINGLET MOLECULAR OXYGEN SENSITIZATION IN HEXADECYLTRIMETHYLAMMONIUM BROMIDE MICELLES
Author(s) -
Daraio Marta E.,
Aramendía Pedro F.,
Román Enrique A. San,
Braslavsky Silvia E.
Publication year - 1991
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.1751-1097.1991.tb02029.x
Subject(s) - singlet oxygen , dimer , chemistry , micelle , photochemistry , bromide , pulmonary surfactant , monomer , zinc , photodissociation , oxygen , singlet state , absorption (acoustics) , reaction rate constant , inorganic chemistry , organic chemistry , materials science , kinetics , excited state , aqueous solution , polymer , biochemistry , physics , quantum mechanics , nuclear physics , composite material
The dimerization of the diamide of zinc‐tetracarboxyphthalocyanine was studied spectro‐scopically in hexadecyltrimethylammonium bromide (CTAB) micelles at surfactant concentrations from 0.026 to 0.1 M and dye concentrations between 0.1 and 10 μ M . The apparent dimerization constant in CTAB 0.1 M is 8.6 × 10 5 M −1 , while the intramicellar dimerization constant is 1.8 × 10 3 . The dimer absorption spectrum was also obtained. Singlet molecular oxygen sensitization was studied by steady state photolysis using 1,3‐diphenylisobenzofurane as scavenger in 0.1 M CTAB. The usual sensitization mechanism is extended to include dimer reactions. Singlet molecular oxygen sensitization yields for monomer and dimer in the micelles are 0.7 and 0.1, respectively. With the reported values it is possible to calculate the average yield of singlet molecular oxygen production at any surfactant and dye concentrations.