Photoacoustic calorimetry study of ligand photorelease from the Ru(II)bis(2,2′-bipyridine)(6,6′-dimethyl-2,2′-bipyridine) complex in aqueous solution

Word, Tarah A.; Whittington, Christi L.; Karolak, Aleksandra; Kemp, Maurice C.; Woodcock, H. Lee; Vaart, Arjan van der; Larsen, Randy W.

doi:10.1016/j.cplett.2014.11.012

Cited by 4 publications

(4 citation statements)

References 43 publications

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“…As a control, [Ru(bpy) 2 dmbpy] 2+ was analyzed and gave a value of 0.10. This is somewhat dissimilar to a previously reported value of 0.19 for this compound . The discrepancy may be due to inaccuracies in the measurement stemming from the rapid photoejection with the Indigo LED.…”

Section: Resultsmentioning

confidence: 99%

Photochemical and Photobiological Activity of Ru(II) Homoleptic and Heteroleptic Complexes Containing Methylated Bipyridyl-type Ligands

Kohler

Nease

et al. 2017

Inorg. Chem.

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Light activated compounds are powerful tools and potential agents for medical applications, as biological effects can be controlled in space and time. Ruthenium polypyridyl complexes can induce cytotoxic effects through multiple mechanisms, including acting as photosensitizers for singlet oxygen (1O2) production, the generation of other reactive oxygen species (ROS), the release of biologically active ligands, or through the creation of reactive intermediates that form covalent bonds to biological molecules. A structure activity relationship (SAR) study was performed on a series of Ru(II) complexes containing isomeric tetramethyl-substituted bipyridyl-type ligands. Three of the ligand systems studied contained strain-inducing methyl groups and created photolabile metal complexes, which can form covalent bonds to biomolecules upon light activation, while the fourth was unstrained and resulted in photostable complexes, which can generate 1O2. The compounds studied included both bis-heteroleptic complexes containing two bipyridine ligands and a third, substituted ligand, and tris-homoleptic complexes containing only the substituted ligand. The photophysics, electrochemistry, photochemistry, and photobiology were assessed. Strained heteroleptic complexes were found to be more photo-active and cytotoxic then tris-homoleptic complexes, and bipyridine ligands were superior to bipyrimidine. However, the homoleptic complexes exhibited an enhanced ability to inhibit protein production in live cells. Specific methylation patterns were associated with improved activation with red light, and photolabile complexes were generally more potent cytotoxic agents than the photostable 1O2 generating compounds.

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Section: Resultsmentioning

confidence: 99%

Photochemical and Photobiological Activity of Ru(II) Homoleptic and Heteroleptic Complexes Containing Methylated Bipyridyl-type Ligands

Kohler

Nease

et al. 2017

Inorg. Chem.

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“…The accessibility of 3 MC states opens several deactivation channels other than 3 MLCT photoluminescence, particularly nonradiative deactivation toward reactant and photodegradation through ligand loss processes . However, despite the fundamental importance of understanding their photoreactivity and the vast amount of experimental data collected in recent years, mechanistic details of photosubstitution processes remain unclear. − Such reactions are difficult to model quantitatively as they typically involve several intercrossing electronic states and different time scales, leading to a scarce number of theoretical mechanistic studies on the photoreactivity itself. − Among them, a large majority deals with the early stage of the photosubstitution reaction, i.e., the photolabilization of the departing ligand, while none of them have addressed the detailed mechanism of formation of the solvent-bound photoproduct. In the particular case of a series of [Ru(tpy)(N–N)(Hmte)] 2+ complexes (tpy = 2,2’:6′,2″-terpyridine, N–N = bpy (2,2′-bipyridine), biq (2,2′-biquinoline), dcbpy (6,6′-dichloro-2,2′-bipyridine),dmbpy (6,6′-dimethyl-2,2′-bipyridine), Hmte = 2-methylthioethanol), a recent static DFT study, which focused on the first steps of the mechanism leading to thioether photolabilization, has shown that the quantum yield of photosubstitution can be rationalized by the existence of two successive nearly degenerate triplet metal-centered ( 3 MC) isomers sharing the same electronic structure.…”

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confidence: 99%

Photoinduced Ligand Exchange Dynamics of a Polypyridyl Ruthenium Complex in Aqueous Solution

Dixon

Bonnet

Alary

et al. 2021

J. Phys. Chem. Lett.

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The understanding of photoinduced ligand exchange mechanisms in polypyridyl ruthenium(II) complexes operating in aqueous solution is of crucial importance to rationalize their photoreactivity. Herein, we demonstrate that a synergetic use of ab initio molecular dynamics simulations and static calculations, both conducted at the DFT level, can provide a full understanding of photosubstitution mechanisms of a monodentate ligand by a solvent water molecule in archetypal ruthenium complexes in explicit water. The simulations show that the photoinduced loss of a monodentate ligand generates an unreactive 16-electron species in a hitherto undescribed pentacoordinated triplet excited state that converts, via an easily accessible crossing point, to a reactive 16-electron singlet ground state, which combines with a solvent water molecule to yield the experimentally observed aqua complex in less than 10 ps. This work paves the way for the rational design of novel photoactive metal complexes relevant for biological applications.

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“…Experimental UV–vis absorption (top, Word et al 76 and this paper) and TD M06 spectra (bottom) of Ru(bipy) 3 2+ . Vertical excitations for the in vacuo TD M06 spectrum are reported as orange spikes.…”

Section: Computational Detailsmentioning

confidence: 96%

“…Theoretical calculations were carried out both in the gas phase, i.e., without solvent, and with water and acetonitrile solvents modeled with the polarizable continuum method (PCM) to take into account the effect of the environment on the excitation energies. 75 The simulated UV–vis absorption spectra at the TD-DFT level of theory are compared with the experimental optical profiles for Ru(bipy) 3 2+ complexes in water 76 and acetonitrile solvents. The latter experimental data were generated within the framework of this work (vide infra for details on the experimental part).…”

Section: Computational Detailsmentioning

confidence: 99%

Optical Properties of Isolated and Covalent Organic Framework-Embedded Ruthenium Complexes

et al. 2019

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Heterogenization of RuL 3 complexes on a support with proper anchor points provides a route toward design of green catalysts. In this paper, Ru(II) polypyridyl complexes are investigated with the aim to unravel the influence on the photocatalytic properties of varying nitrogen content in the ligands and of embedding the complex in a triazine-based covalent organic framework. To provide fundamental insight into the electronic mechanisms underlying this behavior, a computational study is performed. Both the ground and excited state properties of isolated and anchored ruthenium complexes are theoretically investigated by means of density functional theory and time-dependent density functional theory. Varying the ligands among 2,2′-bipyridine, 2,2′-bipyrimidine, and 2,2′-bipyrazine allows us to tune to a certain extent the optical gaps and the metal to ligand charge transfer excitations. Heterogenization of the complex within a CTF support has a significant effect on the nature and energy of the electronic transitions. The allowed transitions are significantly red-shifted toward the near IR region and involve transitions from states localized on the CTF toward ligands attached to the ruthenium. The study shows how variations in ligands and anchoring on proper supports allows us to increase the range of wavelengths that may be exploited for photocatalysis.

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Photoacoustic calorimetry study of ligand photorelease from the Ru(II)bis(2,2′-bipyridine)(6,6′-dimethyl-2,2′-bipyridine) complex in aqueous solution

Cited by 4 publications

References 43 publications

Photochemical and Photobiological Activity of Ru(II) Homoleptic and Heteroleptic Complexes Containing Methylated Bipyridyl-type Ligands

Photochemical and Photobiological Activity of Ru(II) Homoleptic and Heteroleptic Complexes Containing Methylated Bipyridyl-type Ligands

Photoinduced Ligand Exchange Dynamics of a Polypyridyl Ruthenium Complex in Aqueous Solution

Optical Properties of Isolated and Covalent Organic Framework-Embedded Ruthenium Complexes

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