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Download fileTuning Magnetic Relaxation in a Tb-Nitronyl Nitroxide Complex by Using Cocrystalline Paramagnetic Complex
journal contribution
posted on 2015-12-07, 00:00 authored by Juan-Juan Wang, Juan Sun, Meng Yang, Li-Cun LiNew
2p–4f and 2p–3d–4f compounds [Tb(hfac)3(NIT-PhNO2)2]·0.5C7H16 (1) and [Ln(hfac)3(NIT-PhNO2)2]2[Cu(hfac)2(NIT-PhNO2)2] (LnIII = Gd 2, Tb 3; hfac = hexafluoroacetylacetonate; NIT-PhNO2 = 2-(p-nitrophenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide)
have been obtained. Complex 1 consists of mononuclear
trispin [Tb(hfac)3(NIT-PhNO2)2] units
in which two radical ligands are ligated to the Tb(III) ion as monodentate
ligands through the NO groups, while complexes 2 and 3 contain two kinds of trispin moieties, namely, [Ln(hfac)3(NIT-PhNO2)2] and [Cu(hfac)2(NIT-PhNO2)2]. In the [Cu(hfac)2(NIT-PhNO2)2] moiety, the radicals are bonded
to the copper(II) ion in the axial positions via the nitroxides. For
three compounds, 1D supramolecular chains are formed via the π–π
stacking interactions involving the radical ligands. Magnetic investigations
show that both Tb complexes exhibit slow relaxation of magnetization
at low temperature; strikingly, complex 3 displays a
higher energy barrier than that of 1. It represents the
first example to use the paramagnetic complex to tune magnetic relaxation
of 4f-based compounds.
