Quenching Dynamics of the Photoluminescence of [Ru(bpy)<sub>3</sub>]<sup>2+</sup>-Pendant PAMAM Dendrimers by Nitro Aromatics and Other Materials

Glazier, Samantha; Barron, Jason A.; Morales, Nelson; Ruschak, Amy M.; Houston, Paul L.; Abruña, Héctor D.

doi:10.1021/ma020045f

Cited by 42 publications

(36 citation statements)

References 36 publications

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“…43,44 For the sake of completeness, the main points are summarized in Table 1. The electroluminescence (EL) spectra were found to be similar to the photoluminescence (PL) spectra from spin-coated films.…”

Section: Resultsmentioning

confidence: 99%

“…[41][42][43][44] stimulated not only by their redox chemistry but also by their photophysical behavior. In this regard, the study of dendrimers containing pendant [Ru(bpy) 3 ] +2 chromophores is of particular interest.…”

Section: Introductionmentioning

confidence: 99%

“…44 This seems to be due, at least in part, to the folding nature of the dendrimers. As the dendrimers become larger they begin to displace the solvent around the chromophore and change its solvation.…”

Section: Introductionmentioning

confidence: 99%

“…In the case of the poly(amidoamine) starburst dendrimers used in this paper, the proximity of the chromophores initially decreases from generation 0 to generation 2. 44 In this regime, the additional bond length of each generation offsets the increase in the number of chromophores. In going from generation 2 to higher generations, de Gennes dense packing takes effect, the crowding factor rapidly increases, and we observe a significant decrease in the quantum efficiency of the molecules in solution.…”

Section: Introductionmentioning

confidence: 99%

“…In going from generation 2 to higher generations, de Gennes dense packing takes effect, the crowding factor rapidly increases, and we observe a significant decrease in the quantum efficiency of the molecules in solution. 26,44,45 The use of these systems in OLEDs allows us to further elucidate what roles the concentration and density of the chromophore play in transport and luminescence. They also allow us to determine what effect the supramolecular architecture has on device performance and to gain further information on the role that the dendrimer structure plays on the photophysics of [Ru(bpy) 3 ] +2 in a solid-state environment.…”

Section: Introductionmentioning

confidence: 99%

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Electroluminescence in Ruthenium(II) Dendrimers

Barron¹,

Bernhard²,

Houston³

et al. 2003

J. Phys. Chem. A

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We have investigated the electroluminescent properties of polyamidoamine dendrimers containing pendant [Ru(bpy) 3 ] +2 chromophores. Devices were made using indium tin oxide (ITO) and gold electrodes, and they were compared to devices made from [Ru(bpy) 3 ]+2 films. The turn-on time, steady-state current, and electroluminescence efficiency were analyzed in order to provide information about the ionic and electronic carrier mobilities and the degree of self-quenching of luminescence in these materials.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Electroluminescence in Ruthenium(II) Dendrimers

Barron¹,

Bernhard²,

Houston³

et al. 2003

J. Phys. Chem. A

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Sensing of 2,4,6‐Trinitrotoluene (TNT) and 2,4‐Dinitrotoluene (2,4‐DNT) in the Solid State with Photoluminescent Ru^II and Ir^III Complexes

Mosca

Khnayzer

Lazorski

et al. 2015

Chemistry A European J

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A series of metal-organic chromophores containing Ru(II) or Ir(III) were studied for the luminometric detection of nitroaromatic compounds, including trinitrotoluene (TNT). These complexes display long-lived, intense photoluminescence in the visible region and are demonstrated to serve as luminescent sensors for nitroaromatics. The solution-based behavior of these photoluminescent molecules has been studied in detail in order to identify the mechanism responsible for metal-to-ligand charge-transfer (MLCT) excited state quenching upon addition of TNT and 2,4-dinitrotoluene (2,4-DNT). A combination of static and dynamic spectroscopic measurements unequivocally confirmed that the quenching was due to a photoinduced electron transfer (PET) process. Ultrafast transient absorption experiments confirmed the formation of the TNT radical anion product following excited state electron transfer from these metal complexes. Reported for the first time, photoluminescence quenching realized through ink-jet printing and solid-state titrations was used for the solid-state detection of TNT; achieving a limit-of-quantitation (LOQ) as low as 5.6 ng cm(-2). The combined effect of a long-lived excited state and an energetically favorable driving force for the PET process makes the Ru(II) and Ir(III) MLCT complexes discussed here particularly appealing for the detection of nitroaromatic volatiles and related high-energy compounds.

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Direct Voltammetric Evidence for a Reducing Agent Generated from the Electrochemical Oxidation of Tripropylamine for Electrochemiluminescence of Ruthenium Tris(bipyridine) Complexes?

et al. 2003

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After the initial suggestion [1] involving the simultaneous electrochemical formation of [Ru(bpy) 3 ] 3 (bpy 2,2'-bipyridine) and tripropylamine (TPA) cation radical [(C 3 H 7 ) 3 N]. , referred to here as TPA . , several mechanisms for [Ru(bpy) 3 ] 2 /TPA electrochemiluminescence (ECL) system have been proposed and examined.[2±5] In all these proposals, a strong reducing agent, which is believed to be a free radical produced from the deprotonation of the cation radical TPA. , serves as a key coreactant in the course . , which, contrary to the previous conception, is considered to be reasonably long-lived and evidenced by its electron spin resonance (ESR) signal.[5]Although the search for voltammetric evidence of TPA . failed, this mechanism provides an explanation for the luminescence observed at potentials where the electrochemical oxidation of [Ru(bpy) 3 ] 2 does not occur. It was also used to explain the ECL that is thought to be generated from the microbead surface out of the electrode diffusion layer in the commercial immunoassay systems.[6±7] As a fundamental factor in this mechanism, the redox potential of the reducing radical must be more negative than À 1.48 V (vs. Ag/AgCl), a value for the [Ru(bpy) . is formed. Therefore, instead of searching for TPA . , the study reported here was focused on tracing voltammetric evidence for the reducing agent and its oxidized product Pr. Although the ECL studies [1±5] mentioned above were carried out in aqueous solutions, a nonaqueous system is suitable for the electrochemical study of TPA. Cyclic voltammograms (CVs) of TPA were first recorded using a platinum-disk working electrode (0.785 mm 2 ) in acetonitrile solutions with tetrabutylammonium hexafluorophosphate (TBAPF 6 , 0.1 M) as a supporting electrolyte and silver wire as a quasi-reference electrode, which was calibrated with the ferrocene/ferrocenium (Fc/Fc ) redox couple by taking E8 Fc/Fc 0.35 V vs. Ag/AgCl. The details of the procedure and the specially designed cell connected with a vacuum line for removing water and oxygen were described previously.[10±11] To rule out the possibility of any redox active impurity existing in the system, we scanned the potential, firstly, downwards from À 0.28 to À 2.28 V and then upwards to 1.02 V. After sufficient amount of TPA was oxidized (oxidation peak appeared), the scan was reversed to move downwards until a cathodic wave was found. Once a cathodic wave was detected, multiple cyclic scans around the wave were followed. Figure 1 demonstrates a typical experimental result. During the initial scan from À 0.28 to À 2.28 V, no redox wave was detected. It indicates that no electrochemically active impurity existed in the system and that TPA itself cannot be reduced. As expected, after TPA undergoes an electrochemical oxidation and the potential scanning is switched back, a cathodic wave with a peak potential (E pc ) equal to À 1.02 V can be found. The follow-up multiple scans between À 1.48 and À 0.58 V indicate a fair reversibility and stability of the redox coupl...

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Quenching Dynamics of the Photoluminescence of [Ru(bpy)₃]²⁺-Pendant PAMAM Dendrimers by Nitro Aromatics and Other Materials

Cited by 42 publications

References 36 publications

Electroluminescence in Ruthenium(II) Dendrimers

Electroluminescence in Ruthenium(II) Dendrimers

Sensing of 2,4,6‐Trinitrotoluene (TNT) and 2,4‐Dinitrotoluene (2,4‐DNT) in the Solid State with Photoluminescent Ru^II and Ir^III Complexes

Direct Voltammetric Evidence for a Reducing Agent Generated from the Electrochemical Oxidation of Tripropylamine for Electrochemiluminescence of Ruthenium Tris(bipyridine) Complexes?

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Quenching Dynamics of the Photoluminescence of [Ru(bpy)3]2+-Pendant PAMAM Dendrimers by Nitro Aromatics and Other Materials

Cited by 42 publications

References 36 publications

Electroluminescence in Ruthenium(II) Dendrimers

Electroluminescence in Ruthenium(II) Dendrimers

Sensing of 2,4,6‐Trinitrotoluene (TNT) and 2,4‐Dinitrotoluene (2,4‐DNT) in the Solid State with Photoluminescent RuII and IrIII Complexes

Direct Voltammetric Evidence for a Reducing Agent Generated from the Electrochemical Oxidation of Tripropylamine for Electrochemiluminescence of Ruthenium Tris(bipyridine) Complexes?

Contact Info

Product

Resources

About

Quenching Dynamics of the Photoluminescence of [Ru(bpy)₃]²⁺-Pendant PAMAM Dendrimers by Nitro Aromatics and Other Materials

Sensing of 2,4,6‐Trinitrotoluene (TNT) and 2,4‐Dinitrotoluene (2,4‐DNT) in the Solid State with Photoluminescent Ru^II and Ir^III Complexes