A series of Ln(4)(III) clusters: Dy(4) single molecule magnet and Tb(4) multi-responsive luminescent sensor for Fe(3+), CrO(4)(2−)/Cr(2)O(7)(2−) and 4-nitroaniline

Five tetranuclear lanthanide clusters of compositions [Ln(4)L(4)(NO(3))(2)(Piv)(2)]·2CH(3)OH (Ln = Gd (1), Tb (2), Dy (3), Ho (4), Er (5); H(2)L = 2-(((2-hydroxy-3-methoxybenzyl)imino)methyl)-6-methoxyphenol; Piv = pivalic acid) were synthesized under solvothermal conditions. The structures of 1–5 were characterized by single-crystal X-ray crystallography. Complexes 1–5 possess a zig-zag topology with [Ln(4)O(6)] cores being formed by the fusion of oxygen atom-bridged two [Ln(2)O(2)] moieties. Direct-current magnetic susceptibility studied in the 2–300 K range revealed weak antiferromagnetic interactions in 1, 2, 4, 5 and ferromagnetic interactions in 3. Complex 3 exhibits single molecule magnet (SMM) behavior. The luminescence studies indicated that complex 2 can serve as highly sensitive and selective luminescent materials for Fe(3+), CrO(4)(2−), Cr(2)O(7)(2−) and 4-nitroaniline (4-NA), demonstrating that complex 2 should be a potential candidate for multi-responsive luminescent sensor.