Interaction of novel cationic meso-tetraphenylporphyrins in the ground and excited states with DNA and nucleotides

Pavel Kubát, Kamil Lang, Pavel Anzenbacher, Karolina Jursíková, Vladimir Král, Benjamin Ehrenberg

Research output: Contribution to journalArticlepeer-review

93 Scopus citations

Abstract

The syntheses and aggregation properties of novel cationic meso-tetraphenylporphyrins substituted in the para-positions with -CH2(pyridinio)+ (P1), -CH2N+(CH3)3 (P2), -CH2P+(n-butyl)3 (P3), -CH2P+(phenyl)3 (P4), -CH2S+-(CH3)2 (P5) and -CH2SC(NH2)2+ (P6) groups are described. Their use as photosensitizers and their interactions with DNA and nucleotides were studied by optical methods and their properties were compared with those of anionic w(?so-tetrakis(4-sulfonatophenyl)porphyrin (TPPS) and cationic meso-tetrakis(4-N-methylpyridyl)porphyrin (TMPyP). P1 and P2 formed stable complexes with calf thymus DNA in phosphate buffer (Ka ∼ 106 M-1; outside stacking binding mode) and with some nucleotides in methanol (Ka ∼103-104 M-1). P3-P6 aggregated readily in aqueous solution due to their more hydrophobic nature. The cationic porphyrins TMPyP and P1-P6 sensitized the decomposition of guanosine 5′-monophosphate (GMP). The rates of GMP decomposition were found to be greater with cationic porphyrins P1-P6 than with anionic TPPS, presumably because of Coulombic attraction between the positively charged porphyrins P1-P6 and the anionic GMP. In oxygen-free conditions, GMP decomposition was initiated by interaction of the singlet (P1, P2) or triplet (P1-P6) excited states of the porphyrins with GMP. In the presence of oxygen, GMP is decomposed predominantly via singlet oxygen mechanism.

Original languageEnglish
Pages (from-to)933-941
Number of pages9
JournalJournal of the Chemical Society, Perkin Transactions 1
Issue number6
DOIs
StatePublished - 2000

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