A family of multi-spin rare-earth complexes based on a triazole nitronyl nitroxide radical: synthesis, structure and magnetic properties. Issue 28 (24th April 2018) - Chen, Peng Yun
Abstract : Three Ln III –triazole–radical complexes have been synthesized, which exhibit interesting magnetic properties. The Tb III complex shows frequency-dependent ac magnetic susceptibilities, which suggests the presence of slow magnetic relaxation. Abstract : The combination of Ln III ions (Gd III, Tb III or Dy III ) and a triazole nitronyl nitroxide radical (4-Me-3-NITtrz) as spin carriers results in two mononuclear and one binuclear compounds, namely, [Ln(hfac)3 (4-Me-3-NITtrz)(H2 O)] (Ln = Gd(1 ), Tb(2 ); hfac = hexafluoroacetylacetone; 4-Me-3-NITtrz = 2-[3-(4-methyl-l, 2, 4-triazolyl)]-4, 4, 5, 5-tetramethylimidazoline-1-oxyl-3-oxide) and [Dy(hfac)2 (4-Me-3-NITtrz)2 ][Dy(hfac)4 ]·CHCl3 . Compounds1 and2 are isostructural and crystallize in the P 1̄ space group, whereas compound3 crystallizes in the P 21 / n space group. In1 and2, the central Ln III ions are nine-coordinated (LnNO8 ) in a distorted spherical capped square antiprism geometry ( C 4v ) finished by three bischelate hfac anions and one bidentate triazole radical and one aqua molecule. While3 is a mixed-coordinated binuclear compound with Dy1 in a triangular dodecahedron ( D 2d ) coordination sphere and Dy2 in a biaugmented trigonal prism ( C 2v ) coordination sphere. Magnetic studies show that compound2 exhibits field-induced single-molecule magnet (SMM) behavior.