Probing DNA Using Metal Complexes

Marcélis, Lionel; Vanderlinden, Willem; Mesmaeker, Andrée Kirsch‐De

doi:10.1002/9781118682975.ch6

Cited by 3 publications

(9 citation statements)

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“…In the last few years, the group of Kirsch-De Mesmaeker focused its attention on the detection of nucleic acids using metal complexes. 100 As an example, they employed highly photo-reactive Ru complexes to irreversibly crosslink ODNs to a DNA target sequence. A photoinduced electron transfer (PET) takes place between a Ru complex and the guanine present in close vicinity in the complementary DNA sequence.…”

Section: Ruthenium Complexes In Pactmentioning

confidence: 99%

Combination of Ru(ii) complexes and light: new frontiers in cancer therapy

et al. 2015

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Section: Ruthenium Complexes In Pactmentioning

confidence: 99%

Combination of Ru(ii) complexes and light: new frontiers in cancer therapy

et al. 2015

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“…11,25,26 AFM studies have also shown that such photocross-linkings can even occur between G bases belonging to different portions of a DNA plasmid. 11,26 These discoveries have prompted us to try to understand the origin of such crosslinking processes.…”

Section: Introductionmentioning

confidence: 99%

“…Polypyridyl ruthenium complexes have been the focus of numerous studies dealing with their photophysical and photochemical properties for many years. Thus, since the first studies of [Ru(bpy) 3 ] 2+ (bpy = 2,2′-bipyridine), − numerous new ligands generating novel Ru II complexes have been prepared and used in various research fields such as solar energy conversion, water splitting, , molecular machines, , and in biological applications. − Among the various ligands that have been developed not only for complexation with the Ru ion but also with other transition metal ions, the TAP ligand (TAP = 1,4,5,8-tetraazaphenanthrene) and derivatives have been the subject of increasing interest in the literature during these last few years. − In spite of the TAP similarity with the extensively used phen ligand (phen = 1,10-phenanthroline), the two supplementary N atoms of TAP (Figure ) are the origin of its attractive properties in coordination chemistry as exemplified also in the present work. Due to its enhanced π-deficiency, the TAP confers to the corresponding complexes an increased photo-oxidation power as compared to phen-equivalent complexes.…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, in the presence of a reducing agent this results in a photoinduced electron transfer (ET). More particularly in the area of biology, the Ru compounds based on this TAP ligand are of peculiar interest. ,− ,, In the presence of DNA, , the ET process takes place between the DNA guanine (G) bases and the complex under irradiation. This photoinduced ET produces radical species that either give rise to the back electron transfer (BET) process with regeneration of the starting material or after several reaction steps lead to a final photoproduct.…”

Section: Introductionmentioning

confidence: 99%

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Photoaddition of Two Guanine Bases to Single Ru-TAP Complexes. Computational Studies and Ultrafast Spectroscopies to Elucidate the pH Dependence of Primary Processes

et al. 2015

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The covalent photoadduct (PA) between [Ru(TAP)3](2+) (TAP = 1,4,5,8-tetraazaphenanthrene) and guanosine monophosphate (GMP) opened the way to interesting photobiological applications. In this context, the PA's capability upon illumination to give rise to the addition of a second guanine base is especially interesting. The origins of these intriguing properties are for the first time thoroughly investigated by an experimental and theoretical approach. The PA's spectroscopic and redox data combined with TDDFT results corroborated with resonance Raman data show that the properties of this PA (pKa around 7) depend on the solution pH. Theoretical results indicate that the acid form PA.H(+) when excited should relax to MLCT (metal-to-ligand charge transfer) excited states, in contrast to the basic form PA whose excited state should have LLCT/ILCT (ligand-to-ligand charge transfer/intra ligand charge transfer) characteristics. Ultrafast excitation of PA.H(+) at pH 5.9 produces continuous dynamic processes in a few hundred picoseconds involving coupled proton-electron transfers responsible for luminescence quenching. Long-lived species of a few microseconds capable of reacting with GMP are produced at that pH, in agreement with the formation of covalent addition of a second GMP to PA, as shown by mass spectrometry results. In contrast, at pH 8 (mainly nonprotonated PA), other ultrafast transient species are detected and no GMP biadduct is formed in the presence of GMP. This pH dependence of photoreaction can be rationalized with the different nature of the excited states, thus at pH 8, unreactive LLCT/ILCT states and at pH 5.9 reactive MLCT states.

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“…Most of these have been examined as DNA photoprobes because their luminescence, quenched in water, is switched on in the presence of DNA. [7] In contrast, the use of highly π-deficient ligands such as 1,4,5,8-tetraazaphenanthrene (TAP) or 1,4,5,8,9,12-hexaazatriphenylene (HAT) enhances the photo-oxidizing power of the resulting complex, so that a photoinduced electron transfer (PET) from a guanine (G) base of DNA towards the excited complex leads to luminescence quenching. [4] Interestingly, the recombination of the two radical species generated by this PET process produces an irreversible covalent adduct between the guanine (G) moiety and the Ru II complex (Figure 1, a).…”

Section: Introductionmentioning

confidence: 99%