[ReF(6)](2-) : a robust module for the design of molecule-based magnetic materials.
A facile synthesis of the [ReF6 ](2-) ion and its use as a building block to synthesize magnetic systems are reported. Using dc and ac magnetic susceptibility measurements, INS and EPR spectroscopies, the magnetic properties of the isolated [ReF6 ](2-) unit in (PPh4 )2 [ReF6 ]⋅2 H2 O (1) have been fully studied including the slow relaxation of the magnetization observed below ca. 4 K. This slow dynamic is preserved for the one-dimensional coordination polymer [Zn(viz)4 (ReF6 )]∞ (2, viz=1-vinylimidazole), demonstrating the irrelevance of low symmetry for such magnetization dynamics in systems with easy-plane-type anisotropy. The ability of fluoride to mediate significant exchange interactions is exemplified by the isostructural [Ni(viz)4 (ReF6 )]∞ (3) analogue in which the ferromagnetic Ni(II) -Re(IV) interaction (+10.8 cm(-1) ) dwarfs the coupling present in related cyanide-bridged systems. These results reveal [ReF6 ](2-) to be an unique new module for the design of molecule-based magnetic materials.
Department of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen (Denmark); CNRS, CRPP, UPR 8641, 33600 Pessac (France); Univ. Bordeaux, CRPP, UPR 8641, 33600 Pessac (France). ksp@kiku.dk.
Kasper S
KS
Pedersen
Marc
M
Sigrist
Mikkel A
MA
Sørensen
Anne-Laure
AL
Barra
Thomas
T
Weyhermüller
Stergios
S
Piligkos
Christian Aa
CA
Thuesen
Morten G
MG
Vinum
Hannu
H
Mutka
Høgni
H
Weihe
Rodolphe
R
Clérac
Jesper
J
Bendix
coordination polymers; fluoride; magnetic anisotropy; rhenium; single-molecule magnets