Series of Lanthanide–Mercury Compounds with Three-Dimensional Structures: Rational Preparation, Structures and Properties

Three novel Ln–Hg complexes [Ln­(H2O)2(μ-IA)3Hg3Br6]n (Ln = Pr (1), Nd (2), and Er (3); HIA is isonicotinic acid) are synthesized and characterized. They feature three-dimensional (3-D) motifs. Solid-state UV/vis diffuse reflectance spectroscopy found that their band gaps are 4.91, 4.59, and 2.68 eV. It is found that lanthanide ions could adjust the band structures of semiconductors. Their photoluminescence comes from their characteristic emissions of 1D2 → 3H4 of Pr3+, 7F7/2 → 4S3/2 and 4F3/2 → 4I9/2 of Nd3+, and 4I15/2 → 4F7/2 and 4I15/2 → 4S3/2 of Er3+. The CIE chromaticity coordinate is (x = 0.5726, y = 0.4206), (x = 0.7268, y = 0.2732), and (x = 0.2923, y = 0.4317). Their magnetization susceptibility totally obeys the Curie–Weiss equation with antiferromagnetic performances