Studies of electrocatalytic DNA cleavage by oxoruthenium(IV). X-ray crystal structure of [Ru(tpy)(tmen)OH2](ClO4)2 (tmen = N,N,N',N'-tetramethylethylenediamine, tpy = 2,2',2''-terpyridine)

Abstract

The interactions of Run(tpy)(bpy)OH22+ (I), RuII(tpy)(phen)OH22+ (2), and Ruu(tpy)(tmen)OH22+ (3) (tpy = 2,2',2"-terpyridine, bpy = 2,2'-bipyridine, phen = 1,10-phenanthroline, tmen = A',A',Ar',N'-tetramethylethylenediamine) with DNA have been investigated by cyclic voltammetry. The addition of DNA to solutions of these complexes causes a dramatic decrease in current for the Ru(IV/III) and Ru(III/II) couples indicative of binding of the complexes to DNA. From the decrease in current, binding constants 15 x 101 23 M'1, 78 X 103 M'1, and 5.3 X 103 M"1 can be estimated for 1-3, respectively. Thus, the binding affinity appears to be partly a function of the extended planarity and aromaticity of the bidentate ligands. The previously reported activity of the Ru(IV) state toward DNA cleavage is apparent as a current enhancement in the Ru(IV/III) oxidation wave. As a result

(2,2'-Biquinoline-κ2N,N')chloro(2,2':6',2''-terpyridine-κ3N,N',N'')ruthenium(II) hexafluorophosphate, [RuCl(C18H12N2)(C15H11N3)][PF6]

“…The largest distortion of the octahedral geometry is due to the geometrical constraints of the terpy ligand, which exhibits small N--Ru--N angles [N31--Rul--N41 --80.3 (3) and N41--Rul--N51 = 79.3 (3) °] and an Ru--N distance for the central pyridyl ring fragment shorter than those for the outer two. These values are in good agreement with those of other structures of ruthenium(II) complexes and the terpy ligand (Adcock, Keene, Smythe & Snow, 1984;Grover, Gupta, Singh & Thorp, 1992;Hecker, Fanwick & McMillin, 1991;Leising et al, 1990;Thummel & Jahng, 1986). The Ru--N distances of 2.071 (6~)-2.103 (6) ,~ for the biq ligand and 2.060 (7)-2.065 (8) A for the non-central terpy ring fragments are in the range found for other ruthenium(II) complexes with pyridyl-type ligands (Eggleston, Goldsby, Hodgson & Meyer, 1985;.…”

Enhanced electrochemical and electrocatalytic activity of a new supramolecular manganese-porphyrin species containing four bis(bipyridine)(aqua)ruthenium(II) complexes

“…According to this result, [O@Ru IV (bipy) 2 (pyP)] 2þ should be the electrocatalytic active species and not the [Ru III (bipy) 2 -(OH)(pyP)] 2þ species. Similar behavior, involving the Ru IV=III oxidation wave, has been reported by Grover et al [57], in the electrocatalytic oxidation of DNA by [Ru(tpy)(bpy)(OH 2 )] 2þ and related complexes. In the range from 0.2 to 250 mM of nitrite ions, a linear response was observed for the modified electrodes, as shown in Fig.…”

DNA-promoted electrochemical assembly of [Ru(bpy)2dpp]3+/2+ on the ITO electrode by introducing copper(II) ion

“…The electrocatalytic oxidation of guanine or DNA in the presence of ruthenium redox mediators has been studied in detail [19][20][21][22][23]. The indirect electrochemical sensing of DNA hybridization by the catalytic oxidation of polypyridyl cobalt complexes in solution has been reported [24].…”