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Ultrafast proton release reaction and primary photochemistry of phycocyanobilin in solution observed with fs-time-resolved mid-IR and UV/Vis spectroscopy

Theiß, Maximilian; Grupe, Merten; Lamparter, Tilman 1; Mroginski, Maria Andrea; Diller, Rolf
1 Karlsruher Institut für Technologie (KIT)

Deactivation processes of photoexcited (λ$_{ex}$ = 580 nm) phycocyanobilin (PCB) in methanol were investigated by means of UV/Vis and mid-IR femtosecond (fs) transient absorption (TA) as well as static fluorescence spectroscopy, supported by density-functional-theory calculations of three relevant ground state conformers, PCB$_{A}$, PCB$_{B}$ and PCB$_{C}$, their relative electronic state energies and normal mode vibrational analysis. UV/Vis fs-TA reveals time constants of 2.0, 18 and 67 ps, describing decay of PCB$_{B}$*, of PCB$_{A}$* and thermal re-equilibration of PCB$_{A}$, PCB$_{B}$ and PCB$_{C}$, respectively, in line with the model by Dietzek et al. (Chem Phys Lett 515:163, 2011) and predecessors. Significant substantiation and extension of this model is achieved first via mid-IR fs-TA, i.e. identification of molecular structures and their dynamics, with time constants of 2.6, 21 and 40 ps, respectively. Second, transient IR continuum absorption (CA) is observed in the region above 1755 cm$^{-1}$ (CA1) and between 1550 and 1450 cm$^{-1}$ (CA2), indicative for the IR absorption of highly polarizable protons in hydrogen bonding networks (X–H…Y). ... mehr

Verlagsausgabe §
DOI: 10.5445/IR/1000133660
Veröffentlicht am 09.06.2021
DOI: 10.1007/s43630-021-00045-7
Zitationen: 2
Web of Science
Zitationen: 2
Zitationen: 2
Cover der Publikation
Zugehörige Institution(en) am KIT Botanisches Institut (BOTANIK)
Publikationstyp Zeitschriftenaufsatz
Publikationsjahr 2021
Sprache Englisch
Identifikator ISSN: 1474-905X, 1474-9092
KITopen-ID: 1000133660
Erschienen in Photochemical and Photobiological Sciences
Verlag Royal Society of Chemistry (RSC)
Nachgewiesen in Web of Science
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