Inverse Kinetic Isotope Effect in the Excited-State Relaxation of a Ru(II)–Aquo Complex: Revealing the Impact of Hydrogen-Bond Dynamics on Nonradiative Decay

Hewitt, Joshua; Concepcion, Javier J.; Damrauer, Niels H.

doi:10.1021/ja4037498

Cited by 31 publications

(32 citation statements)

References 41 publications

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“…For example, upon irradiation in the visible range of a basic solution of ( 1 ) 2+ , its emission becomes weaker and its decay shows biexponential behavior, with a short lifetime component that is more pronounced upon extended times of irradiation (Figure ). This behavior, also observed for ( 2 ) 2+ , indicates that the products of the photolysis, ( 1a ) 2+ and ( 2a ) 2+ , are weak emitters, as found for other Ru II –aquo complexes . The observed change in the emission properties of these complexes upon irradiation provides an alternative way to monitor the photolysis reaction when the reaction conditions preclude the use of visible absorption, as in a heterogeneous medium.…”

Section: Resultssupporting

confidence: 56%

Photosubstitution of Monodentate Ligands from Ru^II–Dicarboxybipyridine Complexes

et al. 2017

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We report the photophysical and photochemical properties of RuII–polypyridine complexes [Ru(bpy)(dcbpy)py2]2+ (1)2+ and [Ru(dcbpy)2py2]2+ (2)2+ (bpy = 2,2′‐bipyridine, dcbpy = 4,4′‐dicarboxy‐2,2′‐bipyridine, py = pyridine). These complexes combine a monodentate ligand with a chelate bipyridine substituted with carboxylate groups. At low pH, both complexes present metal‐to‐ligand charge transfer absorption bands in the visible region and room‐temperature photoluminescence with long excited‐state lifetimes (τ > 200 ns). At physiological pH, their absorption and emission maxima are displaced to higher energies, with a significant reduction of their emission lifetime. These species show photosubstitution of the monodentate pyridine upon irradiation at 450 nm. At low pH, the quantum yield for this process is very low, but at physiological pH, they are very active, with a φPS,450 value of 0.14 for (1)2+ and of 0.17 for (2)2+. The products of photosubstitution were identified as monoaquo complexes. Both the reactants and the products of the photosubstitution show photoluminescence, but with very different lifetimes, making it possible to monitor the reaction by the time constant of their decay. The ability of complexes (1)2+ and (2)2+ to photorelease monodentate ligands at physiological pH makes them attractive candidates for the delivery of biomolecules linked to more complex structures through the carboxylate functional group.

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Section: Resultssupporting

confidence: 56%

Photosubstitution of Monodentate Ligands from Ru^II–Dicarboxybipyridine Complexes

et al. 2017

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“…Following excitation at 505 nm, both compounds give rise to an initial excited state spectrum (ES1 505 nm ) typical of the 3 MLCT states seen in ruthenium polypyridine complexes, 24 , 37 , 40 , 42 – 45 with bleaching in the spectral area of the ground state absorption and a weaker positive transient in the spectral range of >550 nm (3D maps and ES1 505 nm in Fig. 3 and S2 † ).…”

Section: Resultsmentioning

confidence: 98%

“…Spectroelectrochemistry has been successfully used to assign the patterns observed in the differential spectra of the MLCT excited states of ruthenium polypyridines. 24 , 34 – 40 Fig. 2 shows the differential changes for metal oxidation (upper panel) and ligand reduction (middle panel) and both contributions summed up (bottom panel) for RubNCS + and RubCN + .…”

Section: Resultsmentioning

confidence: 99%

Trapping intermediate MLCT states in low-symmetry {Ru(bpy)} complexes

et al. 2017

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“…The ruthenium(II) complexes with polypyridyl ligands have been extensively studied as promising functional molecules due to the unique photochemical [1][2][3][4][5][6] and photophysical [7][8][9] properties related to a photoexcited triplet metal-to-ligand charge transfer ( 3 MLCT) state as well as redox properties including electrochromism [10,11], and the multi-electron transfer catalysis. [12][13][14][15] These properties are responsible for potential applications of the ruthenium(II) complexes to a large variety of devices including sensors [16,17], photovoltaic cells [18][19][20], displays [21,22], and photocatalysts.…”

Section: Introductionmentioning

confidence: 99%

Influence of chloro substituent on photoisomerization, redox reactions and water oxidation catalysis of mononuclear ruthenium complexes

Takahashi

Zhang

Hirahara

et al. 2015

Journal of Photochemistry and Photobiology A: Chemistry

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distal-[Ru(Cl-tpy)(pynp)Cl] + (d-2Cl) (Cl-tpy = 4'-chloro-2,2';6',2"-terpyridine, pynp = 2-(2-pyridyl)-1,8-naphthyridine), and distaland proximal-[Ru(Cl-tpy)(pynp)OH 2 ] 2+ (d-and p-2H 2 O) complexes are newly synthesized and characterized to compare structures and physicochemical properties with a 2,2';6',2"-terpyridine (tpy) ligand derivatives of distal-[Ru(tpy)(pynp)Cl] + (d-1Cl), distal-and proximal-[Ru(tpy)(pynp)OH 2 ] 2+ (d-and p-1H 2 O). The equilibrium turned out to be involved in the aquation reaction of d-2Cl to d-2H 2 O in contrast to observed irreversible aquation reaction of d-1Cl under the same conditions. The kinetic analysis showed that the aquation reaction of d-2Cl is slightly slower than that of d-1Cl. The stoichiometric photoisomerization of d-2H 2 O to p-2H 2 O occurs by visible light irradiation as it is for d-1H 2 O, and Φ (2.1%) at 520 nm for photoisomerization of d-2H 2 O was higher than that (1.5%) observed for d-1H 2 O. d-2H 2 O undergoes the two-step reaction involving the successive one-proton-coupled one-electron reactions of the Ru II-OH 2 /Ru III-OH and Ru III-OH/Ru IV =O redox couples, whereas p-2H 2 O undergoes the one-step reaction involving the two-proton-coupled two-electron reaction of the Ru II-OH 2 /Ru IV =O redox couple. These redox potentials of d-and p-2H 2 O are higher than those for d-and p-1H 2 O at pH = 7.0 by 10 ~ 50 mV due to the electron-withdrawing chloro substitution. The turnover frequency (k O2 = 6.3 × 10-3 s-1) of d-2H 2 O for water oxidation was higher than that (3.9 × 10-4 s-1) of p-2H 2 O by a factor of 16. k O2 for d-2H 2 O was also 1.6 times higher than that (3.8 × 10-3 s-1) for d-1H 2 O, whereas k O2 for p-2H 2 O was 1.2 times lower than that (4.8 × 10-4 s-1) for p-1H 2 O.

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Inverse Kinetic Isotope Effect in the Excited-State Relaxation of a Ru(II)–Aquo Complex: Revealing the Impact of Hydrogen-Bond Dynamics on Nonradiative Decay

Cited by 31 publications

References 41 publications

Photosubstitution of Monodentate Ligands from Ru^II–Dicarboxybipyridine Complexes

Photosubstitution of Monodentate Ligands from Ru^II–Dicarboxybipyridine Complexes

Trapping intermediate MLCT states in low-symmetry {Ru(bpy)} complexes

Influence of chloro substituent on photoisomerization, redox reactions and water oxidation catalysis of mononuclear ruthenium complexes

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Inverse Kinetic Isotope Effect in the Excited-State Relaxation of a Ru(II)–Aquo Complex: Revealing the Impact of Hydrogen-Bond Dynamics on Nonradiative Decay

Cited by 31 publications

References 41 publications

Photosubstitution of Monodentate Ligands from RuII–Dicarboxybipyridine Complexes

Photosubstitution of Monodentate Ligands from RuII–Dicarboxybipyridine Complexes

Trapping intermediate MLCT states in low-symmetry {Ru(bpy)} complexes

Influence of chloro substituent on photoisomerization, redox reactions and water oxidation catalysis of mononuclear ruthenium complexes

Contact Info

Product

Resources

About

Photosubstitution of Monodentate Ligands from Ru^II–Dicarboxybipyridine Complexes

Photosubstitution of Monodentate Ligands from Ru^II–Dicarboxybipyridine Complexes