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Binding of 3 O 2 and 1 O 2 to dyes used in photodynamic therapy in gas phase and aqueous media
Author(s) -
Kushwaha P. S.,
Mishra P. C.
Publication year - 2006
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.20919
Subject(s) - chemistry , proflavine , moiety , density functional theory , aqueous solution , photochemistry , methylene , acridine orange , ring (chemistry) , molecule , methylene blue , crystallography , stereochemistry , computational chemistry , medicinal chemistry , photocatalysis , organic chemistry , dna , apoptosis , biochemistry , catalysis
Abstract Density functional theory (DFT) was employed at the B3LYP/6‐31+G* level to study complexes of 1 O 2 and 3 O 2 with the dye molecules proflavine, methylene blue, and acridine orange, which are useful in photodynamic therapy. It was found that the most stable complex between 1 O 2 and proflavine are formed when 1 O 2 is located above the central ring, while the most stable complex between 1 O 2 and methylene blue is formed when 1 O 2 is located above the molecular plane, but not above any of the rings, near the sulfur atom. 1 O 2 can make a stable complex with acridine orange, as it is located above the outer ring of the dye. The binding energies of the complexes of 1 O 2 with all three dyes are enhanced considerably in going from gas phase to aqueous media. The complexes of 3 O 2 with the dyes will be unstable in all cases, while those of 1 O 2 with the same will be quite stable and will not be dissociated due to thermal fluctuations at room temperature. In the complexes of 1 O 2 and 3 O 2 with the dyes, charge transfer occurs from the dyes to the O 2 moiety, the amount of charge transfer being much more to 1 O 2 than to 3 O 2 in each case. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2006