Five new tri-spin lanthanide–nitronyl nitroxide (LnIII = GdIII, TbIII, DyIII, HoIII, ErIII) complexes: Structures and magnetic properties

Five radical–Ln(III)–radical complexes, [Ln(hfac)3(NITPhOC4H9)2] (Ln = Gd (1), Tb (2), Dy (3), Ho (4), Er (5); hfac = hexafluoroacetylacetonate; and NITPhOC4H9 = 4′-butoxy-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide) have been synthesized, structurally and magnetically characterized. The X-ray crystal structure analysis reveals that the structures of the five complexes are isomorphous in which central Ln(III) ions are coordinated by six oxygen atoms from three hfac and two oxygen atoms from nitronyl radicals. The magnetic studies show that in the Gd(III) complex, there are ferromagnetic Gd(III)–Rad interactions and antiferro-magnetic Rad–Rad interactions in the molecules (with JRad–Gd = 0.19 cm−1, JRad–Gd = −1.91 cm−1). And the analogous complex of [Tb(hfac)3(NITPhOC4H9)2] (2) shows the strong ferromagnetic Tb(III)–Rad interactions.

Graphical abstractA series of radical–Ln(III)–radical complexes have been synthesized and characterized. These complexes show similar structures and coordination modes. Magnetic investigations reveal that ferromagnetic interactions exist in Gd(III)–radical and Tb(III)–radical.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► To explore novel lanthanide–nitronyl nitroxide complexes, we synthesized five tri-spin mononuclear complexes. ► Two Ln(III)–radical complexes exhibit ferromagnetic interactions. ► To explore the magnetic coupling effect of the complexes, the ferromagnetic interaction is favorable.