Ligand Selection in Ru<sup>II</sup> Complexes for Direct One‐Electron Photooxidation of Guanine: A Combined Computational and Experimental Study

Boggio‐Pasqua, Martial; Vicendo, Patricia; Oubal, Mohamed; Alary, Fabienne; Heully, Jean‐Louis

doi:10.1002/chem.200802520

Cited by 12 publications

(6 citation statements)

References 20 publications

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“…Ru͑bpy͒ 3 2+ is not a good example for such electron transfer but other ligands such as 2,2Ј-bipyrazine or dipyrido͓3,2-a :2Ј ,3Ј-c͔phenazine are, as we have shown in a recent paper. 35 The emission spectra from both the D 3 and C 2 MLCT states have been calculated and again, at least for the D 3 MLCT state, the spectra reproduce quite well the experimental data. However, we have shown that it will be very difficult to differentiate the emission from these two states ͑D 3 versus C 2 MLCT͒.…”

Section: Discussionmentioning

confidence: 61%

Spin-orbit effects on the photophysical properties of Ru(bpy)32+

Heully¹,

Alary²,

Boggio‐Pasqua³

2009

The Journal of Chemical Physics

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We present in this article a detailed study of the photophysics of the Ru(bpy)(3)(2+) complex based on a formalism using density functional theory and an a posteriori treatment of the spin-orbit coupling. The absorption and emission spectra were computed and a very good agreement was obtained with the available experimental data. This work also reveals for the first time that the triplet metal-centered (MC) dd state cannot deactivate radiatively and corresponds to a transient structure for the nonradiative de-excitation of the triplet metal-to-ligand charge transfer (MLCT) state. Thus, a competition takes place between the luminescence of the MLCT state and nonradiative decay back to the ground state via population of the MC state. This radiationless return to the ground state occurs via a deactivation funnel which has been characterized for the first time by optimizing the minimum energy crossing point between the triplet MC and singlet ground state potential energy surfaces. Its low-lying energy position relative to the energy necessary to access the MC minimum suggests that this funnel will be readily accessible.

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Section: Discussionmentioning

confidence: 61%

Spin-orbit effects on the photophysical properties of Ru(bpy)32+

Heully¹,

Alary²,

Boggio‐Pasqua³

2009

The Journal of Chemical Physics

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“…Moreover, we have shown that the energy level of the singlet and triplet MLCT states can be tuned by the use of the dab ligand. This ligand can therefore be useful to adjust the energy of the excited state populated after photoabsorption of ruthenium(II) complexes opening new perspectives for photoinduced electron transfer applications. ,, …”

Section: Resultsmentioning

confidence: 99%

Theoretical Investigation on the Photophysical Properties of Model Ruthenium Complexes with Diazabutadiene Ligands [Ru(bpy)_3−x(dab)_x]²⁺ (x = 1−3)

et al. 2010

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In this study we report a theoretical comparative study of some photophysical properties in the [Ru(bpy)(3-x)(dab)(x)](2+) (x = 0-3) series. Density functional theory calculations, validated by highly correlated ab initio benchmark calculations, were used to investigate the absorption and emission properties of the complexes with x = 1-3. The presence of a 1,4-diaza-1,3-butadiene (dab) ligand dramatically changes these properties because of the strong π-acceptor character of this ligand. As a result, comparing to the reference [Ru(bpy)(3)](2+) complex previously studied, we observed (i) a strong red-shift of the maximum of the absorption band, (ii) a strong decrease of the emission energy of the lowest triplet metal-to-ligand charge transfer state, with all the [Ru(bpy)(3-x)(dab)(x)](2+) (x = 1-3) complexes luminescent in the near-infrared region, while [Ru(bpy)(3)](2+) emits in the visible region, and (iii) the triplet metal-centered states become inaccessible in all the [Ru(bpy)(3-x)(dab)(x)](2+) (x = 1-3) complexes. Consequently, these complexes could be potential candidates for infrared light-emitting diodes and probes.

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“…As a first step, the geometries of the ground state of the low-spin Ru(II) (4d 6 valence configuration) complexes were optimized in vacuo using the B3LYP functional. , The 6-31G* basis set , was used for the C, N, and H atoms while the “Stuttgart RSC 1997 ECP” relativistic effective core potential and associated basis set was employed to describe the Ru atom. This potential has been shown to allow an accurate description of the electronic and bonding properties of Ru complexes. − The structures obtained for the [Ru(tap) 3 ] •+ and [Ru(tap) 2 (phen)] •+ complexes display a D 3 and C 2 symmetry, respectively. By performing geometry optimizations in the C 1 symmetry group, we verified that we obtained a higher total energy for both systems.…”

Section: Methodsmentioning

confidence: 99%

Density Functional Theory Interpretation of the ¹H Photo-Chemically Induced Dynamic Nuclear Polarization Enhancements Characterizing Photoreduced Polyazaaromatic Ru(II) Coordination Complexes

et al. 2010

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The unprotonated and protonated monoreduced forms of the polyazaaromatic Ru(II) coordination complexes [Ru(tap)(3)](2+) and [Ru(tap)(2)(phen)](2+) (tap = 1,4,5,8-tetraazaphenanthrene ; phen = 1,10-phenanthroline), that is, [Ru(tap)(3)](*+), [Ru(tap)(2)(phen)](*+), [Ru(tap)(2)(tap-H)](*2+), and [Ru(tap)(tap-H)(phen)](*2+), were studied by Density Functional Theory (DFT). The electron spin density of these radical cations, the isotropic Fermi-contact, and the anisotropic dipolar contributions to the hyperfine coupling constants of the H nuclei were calculated in vacuo and using a continuum model for water solvation. For [Ru(tap)(2)(phen)](*+), as well as for its protonated form, the DFT results show that the unpaired electron is not localized on the phen ligand. For both [Ru(tap)(3)](*+) and [Ru(tap)(2)(phen)](*+), they reveal high electron spin density in the vicinity of tap H-2 and tap H-7 (the H atoms in the ortho position of the tap non-chelating N atoms). These results are in full agreement with recent steady-state (1)H photo-Chemically Induced Dynamic Nuclear Polarization (photo-CIDNP) measurements. The DFT calculations performed for the protonated species also predict major (1)H photo-CIDNP enhancements at these positions. Interestingly, they indicate significantly different polarization for tap H-9,10, suggesting that the occurrence of a photoinduced electron transfer with protonation of the reduced species might be detected by high-precision photo-CIDNP experiments.

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

Cited by 12 publications

References 20 publications

Spin-orbit effects on the photophysical properties of Ru(bpy)32+

Spin-orbit effects on the photophysical properties of Ru(bpy)32+

Theoretical Investigation on the Photophysical Properties of Model Ruthenium Complexes with Diazabutadiene Ligands [Ru(bpy)_3−x(dab)_x]²⁺ (x = 1−3)

Density Functional Theory Interpretation of the ¹H Photo-Chemically Induced Dynamic Nuclear Polarization Enhancements Characterizing Photoreduced Polyazaaromatic Ru(II) Coordination Complexes

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

Cited by 12 publications

References 20 publications

Spin-orbit effects on the photophysical properties of Ru(bpy)32+

Spin-orbit effects on the photophysical properties of Ru(bpy)32+

Theoretical Investigation on the Photophysical Properties of Model Ruthenium Complexes with Diazabutadiene Ligands [Ru(bpy)3−x(dab)x]2+ (x = 1−3)

Density Functional Theory Interpretation of the 1H Photo-Chemically Induced Dynamic Nuclear Polarization Enhancements Characterizing Photoreduced Polyazaaromatic Ru(II) Coordination Complexes

Contact Info

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About

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

Theoretical Investigation on the Photophysical Properties of Model Ruthenium Complexes with Diazabutadiene Ligands [Ru(bpy)_3−x(dab)_x]²⁺ (x = 1−3)

Density Functional Theory Interpretation of the ¹H Photo-Chemically Induced Dynamic Nuclear Polarization Enhancements Characterizing Photoreduced Polyazaaromatic Ru(II) Coordination Complexes