Journal Article

PUBDB-2021-02558

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Ionization and photofragmentation of isolated metalloporphyrin cations investigated by VUV action spectroscopy

Schubert, K.XFEL.EU*DESY* ; Schwob, L. (Corresponding author)XFEL.EU*DESY* ; Dörner, S.Extern*XFEL.EU* ; Girod, M. ; MacAleese, L.Extern*XFEL.EU* ; Pieterse, C. L. ; Schlathölter, T.Extern* ; Techert, S.XFEL.EU*DESY* ; Bari, S. (Corresponding author)DESY*

2021
Wiley-VCH Weinheim

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Please use a persistent id in citations: doi:10.1002/chem.202101515  doi:10.3204/PUBDB-2021-02558

Abstract: We investigated the photoionization and fragmentation of isolated metal protoporphyrin IX cations (MPPIX+ with M=Fe, Co, Zn) by means of vacuum-ultraviolet (VUV) action spectroscopy in the energy range of 8.5–35 eV. Experiments were carried out in the gas phase by interfacing an electrospray ionization tandem mass spectrometer with a synchrotron beamline. The mass spectra and partial ion yields show that photoexcitation of the precursor ions predominantly leads to .CH$_2$COOH radical side-chain losses of the macrocycle with additional methyl radical (.CH$_3$) side-chain losses. Ionization, in contrast, leads to the formation of the intact ionized precursor and various doubly charged fragments which are mostly due to side-chain cleavages. Although statistical fragmentation dominates, we found evidence for non-statistical processes such as new fragments involving for example single and double H2O losses, indicating that different relaxation mechanisms are at play upon photoionization compared to photoexcitation. The measured ionization energies were 9.6±0.2 eV, 9.4±0.2 eV and 9.6±0.2 eV for FePPIX$^+$, CoPPIX$^+$ and ZnPPIX$^+$, respectively.

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Contributing Institute(s):

1. Strukturdynamik Chemischer Systeme (FS-SCS)

Research Program(s):

1. 633 - Life Sciences – Building Blocks of Life: Structure and Function (POF4-633) (POF4-633)
2. DFG project 28586557 - SFB 755: Photonische Abbildungen auf der Nanometerskala (28586557) (28586557)

Experiment(s):

1. Measurement at external facility

Appears in the scientific report 2021

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Database coverage:
; ; ; Chemical Reactions ; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; DEAL Wiley ; Ebsco Academic Search ; Essential Science Indicators ; IF < 5 ; Index Chemicus ; JCR ; Nationallizenz ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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