Diquaternary Salts of 4,4′‐Bipyridine as Electron Relays for the Photoreduction of Water

Summers, L. A.

doi:10.1002/jhet.5570280401

Cited by 21 publications

(4 citation statements)

References 195 publications

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“…The photosensitizer [Ru(bpy) 3 ] 2+ (bpy = 2,2′-bipyridine) is excited with light, and its excited state is quenched by an electron relay compound methyl viologen (MV 2+ ). 15,16 The reduced viologen species (MV •+ ) then delivers an electron to a catalytic center, here cobaloxime. In order to evolve molecular hydrogen (H 2 ), sources of protons and electrons (sacrificial electron donor) are required.…”

Section: ■ Introductionmentioning

confidence: 99%

“…A typical photocatalytic multicomponent system has been described by Gray and co-workers (see Figure ). The photosensitizer [Ru(bpy) 3 ] 2+ (bpy = 2,2′-bipyridine) is excited with light, and its excited state is quenched by an electron relay compound methyl viologen (MV 2+ ). , The reduced viologen species (MV •+ ) then delivers an electron to a catalytic center, here cobaloxime. In order to evolve molecular hydrogen (H 2 ), sources of protons and electrons (sacrificial electron donor) are required.…”

Section: Introductionmentioning

confidence: 99%

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Pump-Flow-Probe X-ray Absorption Spectroscopy as a Tool for Studying Intermediate States of Photocatalytic Systems

et al. 2013

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A new setup for pump-flow-probe X-ray absorption spectroscopy has been implemented at the SuperXAS beamline of the Swiss Light Source. It allows recording X-ray absorption spectra with a time resolution of tens of microseconds and high detection efficiency for samples with sub-mM concentrations. A continuous wave laser is used for the photoexcitation, with the distance between laser and X-ray beams and velocity of liquid flow determining the time delay, while the focusing of both beams and the flow speed define the time resolution. This method is compared with the alternative measurement technique that utilizes a 1 kHz repetition rate laser and multiple X-ray probe pulses. Such an experiment was performed at beamline 11ID-D of the Advanced Photon Source. Advantages, limitations and potential for improvement of the pump-flow-probe setup are discussed by analyzing the photon statistics. Both methods, with Co K-edge probing were applied to the investigation of a cobaloxime-based photo-catalytic reaction. The interplay between optimizing for efficient photoexcitation and time resolution as well as the effect of sample degradation for these two setups are discussed.

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Section: ■ Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Pump-Flow-Probe X-ray Absorption Spectroscopy as a Tool for Studying Intermediate States of Photocatalytic Systems

et al. 2013

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“…Chemistry of heterocycles is always a subject of interest. Besides the fundamental interest in the area of heterocycles, these compounds can be used as intermediates, and fine products for drugs, , color industries, laser dyes, complex-forming agents, , redox systems for solar energy, and organized assemblies . Besides these applications, another area of interest is the study of hydrogen transfer and the prototropism with suitable substituents, for example, amino-, hydroxy-, − and aminophenylbenzazoles .…”

Section: Introductionmentioning

confidence: 99%

Spectral Characteristics of the Various Prototropic Species of 2-(4‘-N,N-Dimethylaminophenyl)pyrido[3,4-d]imidazole

Krishnamoorthy

Dogra

1999

J. Org. Chem.

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Spectral characteristics of 2-(4'-N,N-dimethylaminophenyl)pyrido[3,4-d]imidazole (DMAPPI) have been studied in two different solvents and H(0)/pH/H(-) range of -10 to +16. Combining the results observed in the absorption, fluorescence, and fluorescence excitation spectra, it is found that (i) only one kind of monoanion (deprotonation of >N-H group) and one kind of trication, (ii) two kinds of monocations (MC1 and MC3) in the ground state and (MC2 and MC3) in the excited singlet state, and (iii) three kinds of dications (DC1, DC2, and DC3) are observed. Semiempirical quantum mechanical calculations (AM1) have been carried out on all kinds of ionic species and their resonating structures. The spectral characteristics have been assigned to various prototropic species combining the experimental and theoretical results.

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“…Viologens constitute a very important class of redox mediators (Bird and Kuhn 1981). Usually the substituents on the nitrogens of the bipyridine rings are simple alkyl groups (figure 3), but several compounds with, for example, charged substituents have been synthesized (Summers 1991). The alkyl substituted viologens are in the following abbreviated C~,n,V where n and n' are the number of carbons in the substituents.…”

Section: "4 Systems With Viologens As Mediatorsmentioning

confidence: 99%

Electron transfer through vesicle membranes: Mechanistic ambiguities

Hammarström

Almgren

1993

J Chem Sci

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We have studied transmembrane electron transfer mediated by an amphiphilic viologen (Ct6" r vz +) in lecithin vesicles. There is no long-range electron transfer between viologens bound to opposite interfaces of the vesicle membrane, as is often proposed. Instead we proposed a mechanism where the rate-determining step is the disproportionation of two viologen radical cations (2C16.I,V+cz-CI6.1,V 2+ +C16.rV ~ forming a doubly reduced, uncharged viologen that transfers electrons by rapid transmembrane diffusion and subsequent reduction of electron acceptors. Studies on other redox mediators provided further information. A brief background to the field is given, including comments on work done by others in relevant systems.

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Diquaternary Salts of 4,4′‐Bipyridine as Electron Relays for the Photoreduction of Water

Cited by 21 publications

References 195 publications

Pump-Flow-Probe X-ray Absorption Spectroscopy as a Tool for Studying Intermediate States of Photocatalytic Systems

Pump-Flow-Probe X-ray Absorption Spectroscopy as a Tool for Studying Intermediate States of Photocatalytic Systems

Spectral Characteristics of the Various Prototropic Species of 2-(4‘-N,N-Dimethylaminophenyl)pyrido[3,4-d]imidazole

Electron transfer through vesicle membranes: Mechanistic ambiguities

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