Time-resolved X-ray absorption spectroscopy for the study of molecular systems relevant for artificial photosynthesis

Smolentsev, Grigory; Sundström, Villy

doi:10.1016/j.ccr.2015.03.001

Cited by 44 publications

(30 citation statements)

References 121 publications

(180 reference statements)

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“…Below, we demonstrate how time-resolved X-ray absorption spectroscopy addresses these questions for a multicomponent photocatalytic system for H 2 evolution. Photosensitizers used in such systems have been studied extensively using time-resolved XAS during the last few years, 220–222 and such research was summarized in a recent review 223 . Time-resolved XAS combines optical laser excitation and probing of the sample solution with X-ray pulses from the synchrotron.…”

Section: Intermolecular Charge Transfermentioning

confidence: 99%

Charge migration and charge transfer in molecular systems

Wörner

Arrell

Banerji

et al. 2017

Structural Dynamics

184

163

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The transfer of charge at the molecular level plays a fundamental role in many areas of chemistry, physics, biology and materials science. Today, more than 60 years after the seminal work of R. A. Marcus, charge transfer is still a very active field of research. An important recent impetus comes from the ability to resolve ever faster temporal events, down to the attosecond time scale. Such a high temporal resolution now offers the possibility to unravel the most elementary quantum dynamics of both electrons and nuclei that participate in the complex process of charge transfer. This review covers recent research that addresses the following questions. Can we reconstruct the migration of charge across a molecule on the atomic length and electronic time scales? Can we use strong laser fields to control charge migration? Can we temporally resolve and understand intramolecular charge transfer in dissociative ionization of small molecules, in transition-metal complexes and in conjugated polymers? Can we tailor molecular systems towards specific charge-transfer processes? What are the time scales of the elementary steps of charge transfer in liquids and nanoparticles? Important new insights into each of these topics, obtained from state-of-the-art ultrafast spectroscopy and/or theoretical methods, are summarized in this review.

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Section: Intermolecular Charge Transfermentioning

confidence: 99%

Charge migration and charge transfer in molecular systems

Wörner

Arrell

Banerji

et al. 2017

Structural Dynamics

184

163

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“…The XANES region primarily provides electronic information of the element of interest, e.g., the oxidation state, but can be also used to obtain some structural information. [17][18][19] The EXAFS region contains further detailed structural information such as the geometry and the nearest neighbor distances of the absorber. [20][21][22] We have developed and established a new setup for time-resolved X-ray absorption fine structure spectroscopy experiments at beamline P11 at the PETRA III storage ring at DESY in Hamburg.…”

Section: Introductionmentioning

confidence: 99%

Time-resolved pump and probe x-ray absorption fine structure spectroscopy at beamline P11 at PETRA III

Göries

Dicke

Roedig

et al. 2016

Review of Scientific Instruments

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We report about the development and implementation of a new setup for time-resolved X-ray absorption fine structure spectroscopy at beamline P11 utilizing the outstanding source properties of the low-emittance PETRA III synchrotron storage ring in Hamburg. Using a high intensity micrometer-sized X-ray beam in combination with two positional feedback systems, measurements were performed on the transition metal complex fac-Tris[2-phenylpyridinato-C2,N]iridium(III) also referred to as fac-Ir(ppy)3. This compound is a representative of the phosphorescent iridium(III) complexes, which play an important role in organic light emitting diode (OLED) technology. The experiment could directly prove the anticipated photoinduced charge transfer reaction. Our results further reveal that the temporal resolution of the experiment is limited by the PETRA III X-ray bunch length of ∼103 ps full width at half maximum (FWHM).

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“…[36][37][38][39][40] The microsecond range is most relevant to studying intermediates of catalysts in multicomponent photocatalytic systems. Time-resolved XANES spectroscopye xtendst he possibilities of the method from species observable at steady-state conditions to excited states and transiently formed intermediates of photochemical reactions.…”

mentioning

confidence: 99%

“…Time-resolved XANES spectroscopye xtendst he possibilities of the method from species observable at steady-state conditions to excited states and transiently formed intermediates of photochemical reactions. [36][37][38][39][40] The microsecond range is most relevant to studying intermediates of catalysts in multicomponent photocatalytic systems. [41][42][43][44][45][46] Thus, the time-resolved XANES enables the investigation of the structure of the cobalt photocatalytic intermediate.…”

mentioning

confidence: 99%

Structure of the Co^I Intermediate of a Cobalt Pentapyridyl Catalyst for Hydrogen Evolution Revealed by Time‐Resolved X‐ray Spectroscopy

et al. 2018

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Cobalt polypyridyls are highly efficient water-stable molecular catalysts for hydrogen evolution. The catalytic mechanism explaining their activity is under debate and the main question is the nature of the involvement of pyridyls in the proton transfer: the pentapyridyl ligand, acting as a pentadentate ligand, can provide stability to the catalyst or one of the pyridines can be involved in the proton transfer. Time-resolved Co K-edge X-ray absorption spectroscopy in the microsecond time range indicates that, for the [Co (aPPy)] catalyst (aPPy=di([2,2'-bipyridin]-6-yl)(pyridin-2-yl)methanol), the pendant pyridine dissociates from the cobalt in the intermediate Co state. This opens the possibility for pyridinium to act as an intramolecular proton donor. In the resting state, the catalyst returns to the original six-coordinate high-spin Co state with a pentapyridyl and one water molecule coordinating to the metal center. Such a bifunctional role of the polypyridyl ligands can be exploited during further optimization of the catalyst.

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Time-resolved X-ray absorption spectroscopy for the study of molecular systems relevant for artificial photosynthesis

Cited by 44 publications

References 121 publications

Charge migration and charge transfer in molecular systems

Charge migration and charge transfer in molecular systems

Time-resolved pump and probe x-ray absorption fine structure spectroscopy at beamline P11 at PETRA III

Structure of the Co^I Intermediate of a Cobalt Pentapyridyl Catalyst for Hydrogen Evolution Revealed by Time‐Resolved X‐ray Spectroscopy

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Time-resolved X-ray absorption spectroscopy for the study of molecular systems relevant for artificial photosynthesis

Cited by 44 publications

References 121 publications

Charge migration and charge transfer in molecular systems

Charge migration and charge transfer in molecular systems

Time-resolved pump and probe x-ray absorption fine structure spectroscopy at beamline P11 at PETRA III

Structure of the CoI Intermediate of a Cobalt Pentapyridyl Catalyst for Hydrogen Evolution Revealed by Time‐Resolved X‐ray Spectroscopy

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Structure of the Co^I Intermediate of a Cobalt Pentapyridyl Catalyst for Hydrogen Evolution Revealed by Time‐Resolved X‐ray Spectroscopy