Photoaddition of ruthenium(II)-tris-1,4,5,8-tetraazaphenanthrene to DNA and mononucleotides

Photoreaction of [Ru(hat)2phen]2+ with Guanosine‐5′‐Monophosphate and DNA: Formation of New Types of Photoadducts

“…Figure 1), B = guanine, C = GMP with the phosphate under the form H 2 PO 4 À , and D = GMP with the phosphate under the form HPO 4 2À ; À2H = formation of the covalent bond between the ruthenium(ii) complex and the base with loss of two hydrogen atoms. [13,14,[18][19][20] Illumination time: 3 h. …”

“…Such shifts were observed previously for photoadducts between polyazaaromatic Ru II complexes and GMP. [15,20,38] The ESMS data for the products around 37 min are given in Table 4. The predominant peak (m/z 457.7) would correspond to a photoadduct of [Ru-(hat) 2 …”

“…[15,18,20,38] Steady state illuminations were carried out with the complex alone and in the presence of GMP. No change in the absorption spectra were observed after several hours of illumination of the complex alone; this suggests that [Ru-(hat) 2 2 + (c t ) was kept constant at 5 mm while the DNA concentration (expressed in equivalents of phosphate concentration) was increased; I(t) is the emission intensity (lifetime) in the presence of CT-DNA and I 0 (t 0 ) is the emission intensity (lifetime) in the absence of CT-DNA.…”

“…The two radicals react and lead to formation of a photoadduct with a covalent link between these two species. [4,13,14,[18][19][20] However, most of the TAP based photoreactive complexes studied until now exhibit a low affinity for polynucleotides and DNA.…”

Ligand Selection in RuII Complexes for Direct One‐Electron Photooxidation of Guanine: A Combined Computational and Experimental Study

“…This electron transfer then induces a proton transfer (Scheme 1, step 3). The key step in the mechanism of formation of these photoadducts is the primary one-electron transfer, [5,[7][8][9][10] which is the focus of this work. Because the excited-state redox potential of these complexes can be tuned by the judicious choice and combination of ligands, [11] many Ru II polypyridine complexes have been synthesized.…”