Two Sm/Hg and Gd/Hg bimetallic complexes: Reasonable synthesis, structure and properties

Abstract

Two new lanthanide mercury isonicotinic acid complexes [Sm(IA)3(H2O)2]2n2n(HgCl4)·3nCl·7nH3O·2nH2O (1; IA = isonicotinic acid anion) and {[Gd(IA)3(H3O)2]2(Hg3Br8)}n(nHgBr2)·2nNO3 (2; IA = isonicotinic acid anion) were synthesized. The crystal structures are characterized by single-crystal X-ray diffraction. Complex 1 is characteristic of a one-dimensional (1-D) chain-like structure, while complex 2 features a two-dimensional (2-D) layer-like structure. The photophysical properties of in solid state have been investigated by photoluminescence and solid-state UV/Vis diffuse reflectance spectra. The photoluminescence reveals that they display red or ultraviolet photoluminescence and, the photoluminescence are resulted from the characteristic emissions of the 4f electron intrashell transitions of the 4G5/2 → 6HJ (J = 7/2, 9/2 and 11/2 of the Sm3+ ions in 1) and the 6P7/2 → 8S7/2 of the Gd3+ ions in 2. The CIE (Commission Internationale de I'Éclairage) chromaticity coordinates for 1 are (0.6597, 0.34) and its CCT (Correlated Color Temperature) is 12853 K. The solid-state UV/Vis diffuse reflectance spectra reveal that the semiconductor bandgaps are 5.01 eV and 2.77 eV.