M-O Bonding Beyond the Oxo Wall: Spectroscopy and Reactivity of Cobalt(III)-Oxyl and Cobalt(III)-Oxo Complexes

0517294 - ÚFCH JH 2020 RIV DE eng J - Článek v odborném periodiku
Andris, E. - Navrátil, R. - Jašík, J. - Srnec, Martin - Rodríguez, M. - Costas, M. - Roithová, J.
M-O Bonding Beyond the Oxo Wall: Spectroscopy and Reactivity of Cobalt(III)-Oxyl and Cobalt(III)-Oxo Complexes.
Angewandte Chemie - International Edition. Roč. 58, č. 28 (2019), s. 9619-9624. ISSN 1433-7851. E-ISSN 1521-3773
Grant CEP: GA ČR(CZ) GA18-13093S
GRANT EU: European Commission(XE) 682275
Institucionální podpora: RVO:61388955
Klíčová slova: terminal oxo * electronic-structure * catalytic-reduction * water oxidation * iron complexes * activation * generation * alkanes * C-H activation * cobalt-oxo complexes
Obor OECD: Physical chemistry
Impakt faktor: 12.959, rok: 2019
Způsob publikování: Open access

Terminal oxo complexes of late transition metals are frequently proposed reactive intermediates. However, they are scarcely known beyond Group8. Using mass spectrometry, we prepared and characterized two such complexes: [(N4Py)Co-III(O)](+) (1) and [(N4Py)Co-IV(O)](2+) (2). Infrared photodissociation spectroscopy revealed that the Co-O bond in 1 is rather strong, in accordance with its lack of chemical reactivity. On the contrary, 2 has a very weak Co-O bond characterized by a stretching frequency of <= 659cm(-1). Accordingly, 2 can abstract hydrogen atoms from non-activated secondary alkanes. Previously, this reactivity has only been observed in the gas phase for small, coordinatively unsaturated metal complexes. Multireference ab-initio calculations suggest that 2, formally a cobalt(IV)-oxo complex, is best described as cobalt(III)-oxyl. Our results provide important data on changes to metal-oxo bonding behind the oxo wall and show that cobalt-oxo complexes are promising targets for developing highly active C-H oxidation catalysts.
Trvalý link: http://hdl.handle.net/11104/0302605