Emission wavelength independence of the excitation polarization of tris(bipyridine)ruthenium(2+)

Blakley, R. L.; Myrick, Michael L.; DeArmond, M. Keith

doi:10.1021/ic00276a031

Cited by 9 publications

(9 citation statements)

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“…The excitation polarization spectrum for Ru(bpy) 3 2+ is provided to allow comparison with the data for the PE-substituted complexes. Our data for Ru(bpy) 3 2+ are consistent with previous reports; the complex features a maximum r value of ≈0.15 when the excitation wavelength corresponds to the lowest MLCT transition. The fact that r < 0.4 is believed to be due to the fact that although initial excitation produces a state that is localized on a single bpy ligand, randomization from the original ligand-localized state occurs prior to light emission.…”

Section: Resultssupporting

confidence: 92%

“…The fact that r < 0.4 is believed to be due to the fact that although initial excitation produces a state that is localized on a single bpy ligand, randomization from the original ligand-localized state occurs prior to light emission. This randomization results in emission from a population in which some molecules have their emission dipoles displaced significantly from the absorption dipole 4 Absorption (fine lines, scale at left) and excitation anisotropy (bold lines, scale at right) spectra obtained at 80 K on samples in ethanol/methanol (4:1 v:v) glass: (a) Ru(bpy) 3 2+ ; (b) 44Ru ; (c) 55Ru .…”

Section: Resultsmentioning

confidence: 99%

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Excited-State Structure and Delocalization in Ruthenium(II)−Bipyridine Complexes That Contain Phenyleneethynylene Substituents

et al. 2001

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A comprehensive photophysical study has been carried out on the two complexes [(bpy) 2 Ru(4,4′-PE-bpy)] 2+ and [(bpy) 2 Ru(5,5′-PE-bpy)] 2+ (44Ru and 55Ru, respectively, where bpy ) 2,2′-bipyridine and PE ) phenyleneethynylene). The objective of this work is to determine the effect of the phenyleneethynylene substituents on the properties of the metal-to-ligand charge-transfer excited state. The complexes have been characterized by using UV-visible absorption, photoluminescence, and UV-visible and infrared transient absorption spectroscopy. The results indicate that the MLCT excited state is localized on the PE-substituted bpy ligands. Moreover, the photophysical data indicate that in the MLCT excited state the excited electron is delocalized into the PE substituents and the manifestations of the electronic delocalization are larger when the substituents are in the 4,4′-positions.

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Section: Resultssupporting

confidence: 92%

Section: Resultsmentioning

confidence: 99%

Excited-State Structure and Delocalization in Ruthenium(II)−Bipyridine Complexes That Contain Phenyleneethynylene Substituents

et al. 2001

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“…The detection of rotational motions using these complexes is not an obvious result. A large number of published reports have suggested that the anisotropy and anisotropy decay of the Ru metal-ligand complexes is caused by intermolecular processes such as randomization of the excited state among the three organic ligands and/or interactions with the solvent that result in localization of the excited state after randomization (Yersin and Braun, 1991;Myrick et al, 1987;Blakley et al, 1988;Ferguson et al, 1985). The range of measurable correlation times is determined by the lifetime of the excited state.…”

Section: Olmentioning

confidence: 99%

Metal-ligand complexes as a new class of long-lived fluorophores for protein hydrodynamics

Terpetschnig

Szmacinski

Malak

et al. 1995

Biophysical Journal

193

127

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We describe the use of asymmetric Ru-ligand complexes as a new class of luminescent probes that can be used to measure rotational motions of proteins. These complexes are known to display luminescent lifetimes ranging from 10 to 4000 ns. In this report, we show that the asymmetric complex Ru(bpy)2(dcbpy) (PF6)2 displays a high anisotropy value when excited in the long wavelength absorption band. For covalent linkage to proteins, we synthesized the N-hydroxy succinimide ester of this metal-ligand complex. To illustrate the usefulness of these probes, we describe the intensity and anisotropy decays of [Ru(bpy)2(dcbpy)] when covalently linked to human serum albumin, concanavalin A (ConA), human immunoglobulin G (IgG), and Ferritin, and measured in solutions of increased viscosity. These data demonstrate that the probes can be used to measure rotational motions on the 10 ns to 1.5 microseconds timescale, which so far has been inaccessible using luminescence methods. The present probe [Ru(bpy)2(dcbpy)] can be regarded as the first of a class of metal-ligand complexes, each with different chemical reactivity and spectral properties, for studies of macromolecular dynamics.

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“…A large number of reports have questioned the mechanism of depolarization in the Ru-ligand complexes, which could be due in part to exchange of the excited state energy among the ligands (18). This latter process would not depend on rotational motion of the protein.…”

Section: Immunoassay For Hsamentioning

confidence: 99%

Fluorescence Polarization Immunoassay of a High-Molecular-Weight Antigen Based on a Long-Lifetime Ru-Ligand Complex

Terpetschnig

Szmacinski

Lakowicz

1995

Analytical Biochemistry

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We describe a new class of fluorescence polarization immunoassays based on the luminescence from an asymmetrical Ru-ligand complex. We found that such a complex displays larger polarization values than those of comparable symmetrical complexes and appear to be highly photostable in aqueous solution. We synthesized a conjugatable Ru-ligand complex, which was used to label human serum albumin (HSA) as the antigen. The Ru-ligand complex displays a long decay time near 400 ns when covalently linked to proteins. We found that the steady-state polarization of labeled HSA was sensitive to binding of anti-HSA, resulting in a 200% increase in polarization. The labeled HSA was also used in a competitive format using unlabeled HSA as the antigen. The time-resolved anisotropy decays demonstrate increased correlation times for labeled HSA in the presence of anti-HSA, an effect which was partially reversed in the presence of unlabeled HSA. These results demonstrate the potential of the metal-ligand complexes to be used in the fluorescence polarization immunoassay of high-molecular-weight analytes. The use of such metal-ligand complexes enable fluorescence polarization immunoassays which bypass the usual limitation to low-molecular-weight antigens, which is a consequence of the 2-5 ns decay time of the previously used fluorophores.

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Emission wavelength independence of the excitation polarization of tris(bipyridine)ruthenium(2+)

Cited by 9 publications

References 0 publications

Excited-State Structure and Delocalization in Ruthenium(II)−Bipyridine Complexes That Contain Phenyleneethynylene Substituents

Excited-State Structure and Delocalization in Ruthenium(II)−Bipyridine Complexes That Contain Phenyleneethynylene Substituents

Metal-ligand complexes as a new class of long-lived fluorophores for protein hydrodynamics

Fluorescence Polarization Immunoassay of a High-Molecular-Weight Antigen Based on a Long-Lifetime Ru-Ligand Complex

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