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Abstract: Five novel Ln(III) complexes based on a new nitronyl nitroxide radical have been synthesized, characterized structurally and magnetically: [Ln(hfac)3(NITPh-3-Br-4-OMe)2] (Ln(III)=Eu(1), Gd(2), Tb(3), Dy(4), Ho(5); hfac=hexafluoroacetylacetonate; and NITPh-3-Br-4-OMe=2-3′-Br-4′-methoxyphenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide). The single-crystal structures analyses show that these complexes have similar mononuclear tri-spin structures, in which central Ln(III) ions are all eight coordinated by three hfac molecules and two NITPh-3-Br-4-OMe radicals. The variable-temperature magnetic susceptibility studies reveal the antiferromagnetic interactions between the paramagnetic ions (Ln(III) and radicals) in complexes 1, 2, 3 and 5 and ferromagnetic interaction in complex 4. The luminescence characterizations of complexes Eu(1), Tb(3) and Dy(4) are also studied in this paper. [Copyright &y& Elsevier]

Abstract: Three new lanthanide complexes based on a novel nitronyl nitroxide radical [Ln(hfac)3(NITPhiPr)2] (Ln=Gd(1), Tb(2), Dy(3); hfac=hexafluoroacetylacetonate, NITPhiPr=4′-isopropyl-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide) have been successfully synthesized, characterized structurally and magnetically, which all display radical-Ln(III)-radical tri-spin structures. The magnetic studies reveal the ferromagnetic interactions between the Gd(III) ion and radicals and the antiferromagnetic interaction between two radicals in the complex 1. And both Ln(III)–radical ferromagnetic interactions exist in complexes 2 and 3. [Copyright &y& Elsevier]

Two new lanthanide–radical complexes, [Tb(hfac)3(EtVNIT)2] (1) and [Dy(hfac)3(EtVNIT)2] (2) (EtVNIT = 2-(4′-ethoxy-3′-methoxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide, hfac = 1,1,1,5,5,5-hexafluoroacetylacetonate), were synthesized; both display radical–Ln(III)–radical (Ln=Tb (1), Dy (2)) tri-spin structures. Magnetic studies reveal that interactions between the lanthanide ions and radicals are ferromagnetic. [ABSTRACT FROM PUBLISHER]

Abstract: Three new lanthanide-radical complexes containing the same radical ligand were successfully synthesized, which all display radical-Ln(III)-radical (Ln=Pr (1), Gd (2), Ho(3)) tri-spin structures. The magnetic studies revealed that, for complex 2, the interactions between the Gd(III) ion and radical are ferromagnetic, while the interaction between two radicals is antiferromagnetic. In complexes 1 and 3, antiferromagnetic couplings exist between the lanthanide ions and radicals. [Copyright &y& Elsevier]

Two heterospin complexes [Cu(NIT3Py)(cda)H2O] ·H2O ( 1) and [Cu(NIT2Py)(cda)H2O] ·H2O ·CH3OH ( 2) with CuII ions and pyridyl-substituted nitronyl nitroxide radicals (NIT xPy = 2-( x′-pyridyl)-4,4,5,5-tetramethyl-imidazoline-1-oxyl-3-oxide, x = 3, 2; H2cda = 4-hydroxy-pyridine-2,6-dicarboxylic acid) were synthesized and characterized structurally and magnetically. The single crystal structures show that the two complexes are both two-spin complexes, in which the different radicals make the two complexes have different hydrogen bonding interactions to form 2D and 1D supramolecular network for complexes 1 and 2, respectively. The magnetic measurements indicate that complexes 1 and 2 both exhibit antiferromagnetic interactions between CuII and radicals. [ABSTRACT FROM AUTHOR]

Abstract: Three heterospin complexes [M(NIT4Py)2(cda)H2O] (M=Cu(II) (1), Ni(II) (2), Co(II) (3)) with various paramagnetic 3d metal ions and pyridyl-substituted nitronyl nitroxide radical (NIT4Py=2-(4′-pyridyl)-4,4,5,5-tetramethyl-imidazoline-1-oxyl-3-oxide, H2cda=4-hydroxy-pyridine-2,6-dicarboxylic acid) have been synthesized, characterized structurally and magnetically. The single crystal structures show that complexes 1–3 are isomorphic, and have 2D supramolecular network consisting of [M(NIT4Py)2(cda)H2O] with three paramagnetic centers. The magnetic measurements indicated that complexes 1–3 exhibit all antiferromagnetic interactions between M(II) and radicals with J Cu–rad =−7.30cm−1, J Ni–rad =−3.58cm−1 and J Co–rad =−1.85cm−1, respectively. Their magnetic behaviors were interpreted in terms of the spin polarization mechanism of the π-electrons of NIT4Py and the orthogonality of 3d magnetic orbital of M(II) ion and the 2pπ orbital on the pyridine rings of NIT4Py. [Copyright &y& Elsevier]