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New DNA‐binding ruthenium(II) complexes as photo‐reagents for mononucleotides and DNA
Author(s) -
Moucheron Cécile,
KirschDe Mesmaeker Andrée
Publication year - 1998
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/(sici)1099-1395(199808/09)11:8/9<577::aid-poc53>3.0.co;2-x
Subject(s) - chemistry , ruthenium , chromophore , photochemistry , guanine , ligand (biochemistry) , quenching (fluorescence) , luminophore , dna , luminescence , electron transfer , intercalation (chemistry) , stereochemistry , crystallography , fluorescence , nucleotide , inorganic chemistry , organic chemistry , catalysis , biochemistry , physics , receptor , optoelectronics , quantum mechanics , gene
The spectroscopic properties of two photoprobes for DNA, Ru(phen) 2 (PHEHAT) 2+ and Ru(TAP) 2 (PHEHAT) 2+ (phen = 1,10‐phenanthroline, TAP = 1,4,5,8‐tetraazaphenanthrene, PHEHAT = 1,10‐phenanthrolino[5,6‐ b ]‐1,4,5,8,9,12‐hexaazatriphenylene), were examined and compared with those of complexes containing either an extended planar ligand (DPPZ) or π‐acceptor ligands. The orbitals involved in the absorption and emission processes for Ru(phen) 2 (PHEHAT) 2+ imply the PHEHAT ligand, whereas the chromophore and luminophore for Ru(TAP) 2 (PHEHAT) 2+ are associated with the Ru(II) → TAP MLCT transition. The two complexes exhibit completely different behaviour in the presence of DNA. Whereas Ru(phen) 2 (PHEHAT) 2+ , which does not emit in water, luminesces upon intercalation between the DNA base pairs, the luminescence of Ru(TAP) 2 (PHEHAT) 2+ is quenched by binding to DNA. Emission quenching is also observed in the presence of GMP, with a quenching rate constant of 1.25 × 10 9 l mol −1 s −1 . This strongly suggests the presence of a photo‐induced electron transfer from the guanine residues of GMP or DNA to the excited complex and leads to the conclusion that this complex is a good DNA photoreagent. © 1998 John Wiley & Sons, Ltd.