A [4+2] mixed ligand approach to ruthenium DNA metallointercalators [Ru(tpa)(N–N)](PF6)2 using a tris(2-pyridylmethyl)amine (tpa) capping ligand

Kraft, Sabine Seeberg née; Bischof, Caroline; Loos, Annette; Braun, Sebastian; Jafarova, N. A.; Schatzschneider, Ulrich

doi:10.1016/j.jinorgbio.2009.05.013

Cited by 9 publications

(4 citation statements)

References 48 publications

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“…6,7,12 It is necessary to mention that DFT calculations previously predicted a dppn-based (dppn ) 4,5,9,16-tetraazadibenzo[a,c]naphthacene) HOMO for dppn-containing Ru(II) complexes using DFT methods, in which the dppn ligand possesses the same extended π-system as pydppn. 13,30 It was also reported that the dppn ligand in [Ru(bpy) 2 (dppn)] 2+ can be oxidized by O 2 under photolysis conditions, while the oxidation state of the Ru(II) center remained unchanged. 31 Substitution of pydppn with the cyclometalating pydbnligand in 6 alters the electron density and energy of the molecular orbitals significantly.…”

Section: Resultsmentioning

confidence: 95%

“…The cyclic and square-wave voltammograms of the free pydppn ligand in deoxygenated CH 2 Cl 2 show an irreversible oxidation wave at +1.57 V vs SCE (Figure S2). This oxidation potential is significantly lower than those of other ligands, showing that pydppn is easier to oxidize than pydppz and pydppx. ,, It is necessary to mention that DFT calculations previously predicted a dppn-based (dppn = 4,5,9,16-tetraazadibenzo[ a,c ]naphthacene) HOMO for dppn-containing Ru(II) complexes using DFT methods, in which the dppn ligand possesses the same extended π-system as pydppn. , It was also reported that the dppn ligand in [Ru(bpy) 2 (dppn)] 2+ can be oxidized by O 2 under photolysis conditions, while the oxidation state of the Ru(II) center remained unchanged …”

Section: Resultsmentioning

confidence: 96%

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Effect of Ligands with Extended π-System on the Photophysical Properties of Ru(II) Complexes

et al. 2010

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Density functional theory calculations were performed on a series of six ruthenium complexes possessing tridentate ligands: [Ru(tpy)(2)](2+) (1; tpy = [2,2';6',2'']-terpyridine), [Ru(tpy)(pydppx)](2+) (2; pydppx = 3-(pyrid-2'-yl)-11,12-dimethyldipyrido[3,2-a: 2',3'-c]phenazine), [Ru(pydppx)(2)](2+) (3), [Ru(tpy)(pydppn)](2+) (4; pydppn = 3-(pyrid-2'-yl)-4,5,9,16-tetraazadibenzo[a,c]naphthacene), [Ru(pydppn)(2)](2+) (5), and [Ru(tpy)(pydbn)](+) (6; pyHdbn = 3-pyrid-2'-yl-4,9,16-triazadibenzo[a,c]naphthacene). The calculations were compared to experimental data, including electrochemistry and electronic absorption spectra. The theoretical results reveal that the lowest-lying singlet and triplet states in 4 and 5 are pydppn-based ππ* in character, which are remarkably different from the lowest-lying metal-to-ligand charge transfer (MLCT) states in 1-3. The calculated lowest triplet states in 4 and 5 are consistent with the (3)ππ* states observed experimentally. However, although the extended π-system of pydbn(-) is similar to that of pydppn, the HOMO of 6 lies above those of 4 and 5, resulting in strikingly different spectroscopic properties. Calculations show that the lowest triplet excited state of 6 is a combination of (3)MLCT and (3)ππ*. This work demonstrates that the electronic structure of the tridentate ligand has a pronounced effect on the photophysical properties of ruthenium(II) complexes and that DFT and TD-DFT methods are a useful tool that can be used to predict photophysical and redox properties of transition metal complexes.

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Section: Resultsmentioning

confidence: 95%

Section: Resultsmentioning

confidence: 96%

Effect of Ligands with Extended π-System on the Photophysical Properties of Ru(II) Complexes

et al. 2010

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“…We recently reported that a ruthenium fragment based on the tetradentate ligand tris[(pyridin-2-yl)methyl]-amine (TPA, Figure 1) is an effective photocaging group for nitriles. 25 Even though the Ru(TPA) motif had been investigated in photochemical molecular machines and switches, 35–38 oxidation 39–49 and hydrogenation 50 catalysts, DNA metallointercalators, 51 and for proton-coupled electron transfer properties, 52–56 its behavior as a photocaging group had only been investigated for release of nitric oxide. 57 Gratifyingly, Ru(TPA) showed promising activity as a caging group for nitriles, including stability in buffer and high selectivity for enzyme inhibition under dark versus light conditions.…”

Section: Introductionmentioning

confidence: 99%

Effects of Methyl Substitution in Ruthenium Tris(2-pyridylmethyl)amine Photocaging Groups for Nitriles

et al. 2016

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Four complexes of the general formula [Ru(L)(CH3CN)2](PF6)2, [L = TPA (5), MeTPA (6), Me2TPA (7), and Me3TPA (8)] [TPA = tris[(pyridin-2-yl)methyl]amine, where methyl groups were introduced consecutively onto the 6-position of py donors of TPA, were prepared and characterized by various spectroscopic techniques and mass spectrometry. While 5 and 8 were isolated as single stereoisomers, 6 and 7 were isolated as mixtures of stereoisomers in 2:1 and 1.5:1 ratios, respectively. Steric effects on ground state stability and thermal and photochemical reactivities were studied for all four complexes using 1H NMR and electronic absorption spectroscopies and computational studies. These studies confirmed that the addition of steric bulk accelerates photochemical and thermal nitrile release.

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“…2 Therefore many studies appeared on complexes, which are active against cancer cells. Various biophysical and biochemical properties of rhodium, 3-7 titanium, [8][9][10] ruthenium, [11][12][13][14][15][16][17][18][19][20][21][22][23][24] and many other metal complexes 25,26 were explored.…”

Section: Introductionmentioning

confidence: 99%

Comparison of hydration reactions for “piano-stool” RAPTA-B and [Ru(η6− arene)(en)Cl]+ complexes: Density functional theory computational study

Chval¹,

Futera

Burda

2011

The Journal of Chemical Physics

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The hydration process for two Ru(II) representative half-sandwich complexes: Ru(arene)(pta)Cl(2) (from the RAPTA family) and [Ru(arene)(en)Cl](+) (further labeled as Ru_en) were compared with analogous reaction of cisplatin. In the study, quantum chemical methods were employed. All the complexes were optimized at the B3LYP/6-31G(d) level using Conductor Polarizable Continuum Model (CPCM) solvent continuum model and single-point (SP) energy calculations and determination of electronic properties were performed at the B3LYP∕6-311++G(2df,2pd)/CPCM level. It was found that the hydration model works fairly well for the replacement of the first chloride by water where an acceptable agreement for both Gibbs free energies and rate constants was obtained. However, in the second hydration step worse agreement of the experimental and calculated values was achieved. In agreement with experimental values, the rate constants for the first step can be ordered as RAPTA-B > Ru_en > cisplatin. The rate constants correlate well with binding energies (BEs) of the Pt∕Ru-Cl bond in the reactant complexes. Substitution reactions on Ru_en and cisplatin complexes proceed only via pseudoassociative (associative interchange) mechanism. On the other hand in the case of RAPTA there is also possible a competitive dissociation mechanism with metastable pentacoordinated intermediate. The first hydration step is slightly endothermic for all three complexes by 3-5 kcal∕mol. Estimated BEs confirm that the benzene ligand is relatively weakly bonded assuming the fact that it occupies three coordination positions of the Ru(II) cation.

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A [4+2] mixed ligand approach to ruthenium DNA metallointercalators [Ru(tpa)(N–N)](PF6)2 using a tris(2-pyridylmethyl)amine (tpa) capping ligand

Cited by 9 publications

References 48 publications

Effect of Ligands with Extended π-System on the Photophysical Properties of Ru(II) Complexes

Effect of Ligands with Extended π-System on the Photophysical Properties of Ru(II) Complexes

Effects of Methyl Substitution in Ruthenium Tris(2-pyridylmethyl)amine Photocaging Groups for Nitriles

Comparison of hydration reactions for “piano-stool” RAPTA-B and [Ru(η6− arene)(en)Cl]+ complexes: Density functional theory computational study

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