A new tetrairon(III) single-molecule magnet with enhanced volatility and processability was obtained by partial ﬂuorination of the ancillary β-diketonato ligands. Fluorinated proligand Hpta = pivaloyltriﬂuoroacetone was used to assemble the bis(alkoxido)-bridged dimer [Fe2(OEt)2(pta)4] (1) in crystalline form, from which the new tetranuclear complex [Fe4(L)2(pta)6] (2) was synthesized in a one-pot reaction with H3L = 2-hydroxymethyl-2- phenylpropane-1,3-diol, NaOEt, and FeCl3 in a Et2O:EtOH solvent mixture. The structure of compound 2 was inferred from 1 H NMR, mass spectrometry, magnetic measurements, and DFT calculations. Direct current magnetic data are consistent with the expected metal-centered triangular topology for the iron(III) ions, with an antiferromagnetic coupling constant J = 16.20(6) cm−1 between the central iron and the peripheral ones and consequent stabilization of an S = 5 spin ground state. Alternating current (ac) susceptibility measurements in 0 and 1 kOe static applied ﬁelds show the presence of a thermally activated process for magnetic relaxation, with τ0 = 2.3(1) 10−7 s and Ueff/kB = 9.9(1) K at zero static ﬁeld and τ0 = 2.0(2) 10−7 s and Ueff/kB = 13.0(2) K at 1 kOe. At a pressure of 10−7 mbar, compound 2 sublimates at (440 ± 5) K vs (500 ± 10) K for the nonﬂuorinated variant [Fe4(L)2(dpm)6] (Hdpm = dipivaloylmethane). According to XPS, ToF-SIMS, and ac susceptibility studies, the chemical composition, fragmentation pattern, and slow magnetic relaxation of the pristine material are retained in sublimated samples, suggesting that the molecular structure remains totally unaﬀected upon vapor-phase processing
Rigamonti, L., Piccioli, M., Malavolti, L., Poggini, L., Mannini, M., Totti, F., et al. (2013). Enhanced Vapor-Phase Processing in Fluorinated Fe4 Single-Molecule Magnets. INORGANIC CHEMISTRY, 52(10), 5897-5905.
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|Titolo:||Enhanced Vapor-Phase Processing in Fluorinated Fe4 Single-Molecule Magnets|
|Citazione:||Rigamonti, L., Piccioli, M., Malavolti, L., Poggini, L., Mannini, M., Totti, F., et al. (2013). Enhanced Vapor-Phase Processing in Fluorinated Fe4 Single-Molecule Magnets. INORGANIC CHEMISTRY, 52(10), 5897-5905.|
|Appare nelle tipologie:||1.1 Articolo in rivista|