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Picosecond Transient Absorption Setup for Detection of Short-Lived Photoproducts and Excited States in Molecular Systems

Applicant Wenger Oliver
Number 157687
Funding scheme R'EQUIP
Research institution Institut für Anorganische Chemie Universität Basel
Institution of higher education University of Basel - BS
Main discipline Inorganic Chemistry
Start/End 01.11.2015 - 31.10.2016
Approved amount 210'000.00
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All Disciplines (2)

Discipline
Inorganic Chemistry
Physical Chemistry

Keywords (5)

time-resolved spectroscopy; pump-probe measurements; transient absorption; photoluminescence; electron transfer

Lay Summary (German)

Lead
In diesem Forschungsvorhaben geht es um die Untersuchung von photochemischen Prozessen, die auf einer Zeitskala von wenigen Milliardstel-Sekunden ablaufen. Solche Prozesse sind wichtig in der biologischen Photosynthese und deren Verständnis ist daher auch im Hinblick auf eine künstliche Umwandlung von Sonnenenergie in chemisch gespeicherte Energie bedeutsam.
Lay summary

Konkret geht es um lichtinduzierte Elektronentransfer- und um Energietransferprozesse. Das geförderte Gerät ermöglicht die Beobachtung von äusserst kurzlebigen Reaktionsprodukten, die nach Lichtanregung mit einem kurzen Laserpuls in verschiedenen chemischen Systemen entstehen. Dies beinhaltet sowohl rein künstliche Modellsysteme vom Typ „Donor-Brücke-Akzeptor“ wie auch natürliche Enzyme und Proteine, in denen photochemische Reaktionen ablaufen können. Es ist geplant, dass dieses Gerät von mindestens 5 verschiedenen Forschungsgruppen im Departement Chemie der Universität Basel benutzt wird, und zwar unter der Leitung der Gruppe von Prof. Oliver Wenger.

Direct link to Lay Summary Last update: 10.11.2014

Responsible applicant and co-applicants

Publications

Publication
Improved light absorbance does not lead to better DSC performance: studies on a ruthenium porphyrin–terpyridine conjugate
Lanzilotto Angelo, Büldt Laura A., Schmidt Hauke C., Prescimone Alessandro, Wenger Oliver S., Constable Edwin C., Housecroft Catherine E. (2016), Improved light absorbance does not lead to better DSC performance: studies on a ruthenium porphyrin–terpyridine conjugate, in RSC Adv., 6, 15370-15381.

Associated projects

Number Title Start Funding scheme
144500 Sustainable nanoscale and materials chemistry 01.10.2012 Project funding (Div. I-III)
149067 Structural and photophysical diversity in coordination macrocycles, polymers and networks 01.10.2013 Project funding (Div. I-III)
146231 From organic mixed valence to photoinduced proton-coupled multi-electron transfer 01.10.2013 Project funding (Div. I-III)
144354 Directed Evolution of Artificial Metalloenzymes : Towards Chemical Biology Applications 01.10.2012 Project funding (Div. I-III)

Abstract

Many photophysical and photochemical processes which are relevant for light-to-chemical energy conversion occur on very rapid timescales. Time-resolved UV-Vis absorption spectroscopy has become an indispensable tool in modern photochemistry. Several ongoing Ph. D. theses and postdoctoral research projects in the main applicant’s group ask for a transient absorption spectrometer with picosecond time resolution and an appropriate laser source. Among these projects are for example the investigation of photoinduced multi-electron transfer reactions in order to spatially separate multiple electrons from multiple holes, which is of key importance for producing chemical fuels with sunlight as energy input (projects 1 and 2). Similarly, picosecond transient absorption spectrosocopy will permit mechanistic studies of photoinduced proton-coupled electron transfer (PCET) reactions which will greatly further our current fundamental understanding of this important class of reactions (project 3). The activation of small inert molecules such as H2O, CO2 or N2 will invariably rely on multi-electron, multi-proton chemistry hence the proposed photochemical studies are important in the greater context of solar energy conversion. In addition to the multi-electron transfer and PCET studies, the main applicant’s group aims to explore ultra-long-range (> 100 Å) triplet-triplet energy transfer reactions in suitably designed donor-bridge-acceptor molecules (project 4). This work is relevant for the funneling of excitation energy over great distances to a photochemical reaction center. Studies of controlling long-range electron transfer across organoboron “wires” by coordinating anions complement the portfolio of projects currently planned in the main applicant’s group (project 5).Among the planned projects with co-applicants are: (i) the investigation of photochemical hydrogen production in artificial metalloenzymes based on the biotin-streptavidin technology (with Prof. Thomas R. Ward); (ii) the exploration of the role of the potentially highly redox-active amino acid ergothioneine in peptides and proteins by studies of phototriggered long-range electron transfer (with Prof. Florian P. Seebeck); (iii) the exploration of the photophysics of copper(I) complexes in dye-sensitized solar cells (DSCs) and in light-emitting electrochemical cells (LECs) (with Profs. Edwin C. Constable, Catherine E. Housecroft)); and (iv) the investigation of solvent-mediated electron transfer with cyclophane-based donor-acceptor dyads (with Prof. Marcel Mayor).In each of the proposed projects there is a clear emphasis on understanding elementary reaction steps occurring after photoexcitation, and this experimental approach will ultimately permit the rational design of photochemically functional systems. Toward this end, transient absorption spectroscopy measurements with high temporal resolution (up to ca. 30 ps) are of vital importance. Funding for a transient absorption spectrometer with picosecond time resolution from Hamamatsu (TRASS system) and a picosecond Nd:YVO4/YAG laser from Ekspla (PL2251B-20-SH/TH/FH model) is therefore requested.
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