Beyond the Classical Contributions to Exchange Coupling in Binuclear Transition Metal Complexes

0541747 - ÚOCHB 2022 RIV US eng J - Journal Article
Chalupský, Jakub - Srnec, Martin
Beyond the Classical Contributions to Exchange Coupling in Binuclear Transition Metal Complexes.
Journal of Physical Chemistry A. Roč. 125, č. 11 (2021), s. 2276-2283. ISSN 1089-5639. E-ISSN 1520-5215
R&D Projects: GA ČR(CZ) GA18-13093S; GA ČR(CZ) GJ20-06451Y; GA MŠMT(CZ) LTAUSA19148
Institutional support: RVO:61388963 ; RVO:61388955
Keywords : magnetic properties * metals * exchange coupling * chemical calculations
OECD category: Physical chemistry; Physical chemistry (UFCH-W)
Impact factor: 2.944, year: 2021
Method of publishing: Limited access
https://doi.org/10.1021/acs.jpca.0c11237

Complexes with two or more magnetically coupled metal ions have attracted considerable attention as catalysts of many vital processes, single-molecule magnets, or spin-crossover compounds. Elucidation of their electronic structures is essential for understanding their catalytic and magnetic properties. Here, we provide an unprecedented insight into exchange-coupling mechanisms between the magnetic centers in six prototypical bis-μ-oxo bimetallic M2O2 complexes, including two biologically relevant models of non-heme iron enzymes. Employing multiconfigurational/multireference methods and related orbital entanglement analysis, we revealed the essential and counterintuitive role of predominantly unoccupied valence metal d orbitals in their strong antiferromagnetic coupling. We found that the participation of these orbitals is twofold. First, they enhance the superexchange between the singly occupied d orbitals. Second, they become substantially occupied and thus directly magnetically active, which we perceive as a new mechanism of the exchange interaction between the magnetic transition metal centers.
Permanent Link: http://hdl.handle.net/11104/0319279