Thiacalix[4]arene-Supported Planar Ln₄ (Ln = Tb^III, Dy^III) Clusters: Toward Luminescent and Magnetic Bifunctional Materials

This paper reports the syntheses, crystal structures, and luminescent and magnetic properties of four tetranuclear TbIII (1 and 3) and DyIII (2 and 4) complexes supported by p-phenylthiacalix[4]arene (H4PTC4A) and p-tert-butylthiacalix[4]arene (H4TC4A). All four frameworks can be formulated as [LnIII4(PTC4A/TC4A)2(μ4-OH)Cl3(CH3OH)2(H2O)3], and some methanol and water solvent molecules are occupied in the interstices. The compounds are featured with a sandwichlike unit constructed by two tail-to-tail calixarene molecules and a planar tetragonal (μ4-OH)Ln4 cluster. The photoluminescent analyses suggest that there is an efficient ligand-to-LnIII energy transfer for compounds 1−3 and H4PTC4A is a more efficient “antenna” than H4TC4A. The DyIII compounds exhibit slow magnetic relaxation behavior of single-molecule magnet nature. The substitution of the t-Bu group with a phenyl group at the up-rim of thiacalix[4]arene leads to different extended structures and physical properties of as-synthesized compounds.