Size-dependent reactivity of rhodium deuteride cluster anions Rh3Dn - (n = 0-3) toward dinitrogen: The prominent role of σ donation.
J Chem Phys
; 156(6): 064303, 2022 Feb 14.
Article
em En
| MEDLINE
| ID: mdl-35168360
ABSTRACT
Nitrogen (N2) fixation is a challenging task for chemists. Adsorption of N2 on transition metal (TM) sites has been identified as a prerequisite for activating the very stable N≡N triple bond in both industrial and biological processes. The importance of π back-donation (filled orbitals of TM â π* orbitals of N2) between metal sites and N2 has been well elucidated while the role of another classic orbital interaction, namely σ donation (σ orbitals of N2 â empty orbitals of TM), remains ambiguous. Herein, the size-dependent reactivity of trinuclear rhodium deuteride cluster anions Rh3Dn - (n = 0-3) toward N2 adsorption in the gas phase was investigated experimentally and theoretically. A reverse relationship that higher electron-donating ability of clusters corresponds to lower N2 adsorption reactivity was experimentally observed, which is uncommon in N2 activation by gas-phase species. Theoretical analysis revealed that the σ donation rather than the π back-donation plays a predominant role in the adsorption complexes Rh3DnN2 - and the enhanced reactivity upon D addition is ascribed to the lowered energy levels of active orbitals in Rh3Dn - as n increases. This study provides the first experimental evidence to declare the important role of σ donation and new clues for the design of reactive metal species in nitrogen fixation.
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01-internacional
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MEDLINE
Idioma:
En
Revista:
J Chem Phys
Ano de publicação:
2022
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Article