Photochemical activation of carbon dioxide in Mg+(CO2)(H2O)0,1

Autor: Christian van der Linde, Martin K. Beyer, Milan Ončák, Erik Barwa, Tobias F. Pascher
Rok vydání: 2020
Předmět:
Zdroj: Theoretical Chemistry Accounts. 139
ISSN: 1432-2234
1432-881X
DOI: 10.1007/s00214-020-02640-w
Popis: We combine multi-reference ab initio calculations with UV–VIS action spectroscopy to study photochemical activation of CO2 on a singly charged magnesium ion, [MgCO2(H2O)0,1]+, as a model system for the metal/ligand interactions relevant in CO2 photochemistry. For the non-hydrated species, two separated Mg+ 3s–3p bands are observed within 5.0 eV. The low-energy band splits upon hydration with one water molecule. [Mg(CO2)]+ decomposes highly state-selectively, predominantly via multiphoton processes. Within the low-energy band, CO2 is exclusively lost within the excited state manifold. For the high-energy band, an additional pathway becomes accessible: the CO2 ligand is activated via a charge transfer, with photochemistry taking place on the CO2– moiety eventually leading to a loss of CO after absorption of a second photon. Upon hydration, already excitation into the first and second excited state leads to CO2 activation in the excited state minimum; however, CO2 predominantly evaporates upon fluorescence or absorption of another photon.
Databáze: OpenAIRE
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