Slow magnetic relaxation in Fe(ii) m-terphenyl complexes
Ikusi/ Ireki
Data
2022Egilea
Valentine, Andrew J.
Geer, Ana M.
Blundell, Toby J.
Cliffe, Matthew J.
Davies, E. Stephen
Argent, Stephen P.
Lewis, William
McMaster, Jonathan
Taylor, Laurence J.
Reta Mañeru, Daniel
Kays, Deborah L.
Dalton Transactions 51(47) : 18118-18126 (2022)
Laburpena
Two-coordinate transition metal complexes are exciting candidates for single-molecule magnets (SMMs) because their highly axial coordination environments lead to sizeable magnetic anisotropy. We report a series of five structurally related two-coordinate Fe(II) m-terphenyl complexes (4-R-2,6-Xyl(2)C(6)H(2))(2)Fe [R = tBu (1), SiMe3 (2), H (3), Cl (4), CF3 (5)] where, by changing the functionalisation of the para-substituent (R), we alter their magnetic function. All five complexes are field-induced single-molecule magnets, with relaxation rates that are well-described by a combination of direct and Raman mechanisms. By using more electron donating R groups we were able to slow the rate of magnetic relaxation. Our ab initio calculations predict a large crystal field splitting (> 850 cm(-1)) and sizeable zero-field splitting parameters (ca. -60 cm(-1), |E| < 0.2 cm(-1)) for 1-5. These favourable magnetic properties suggest that m-terphenyl ligands have untapped potential as chemically versatile ligands able to impose highly axial crystal fields.