Three new Hg(II) complexes constructed from mercapto- and amino-containing triazole ligands: Syntheses, crystal structures and luminescent properties

Three new mercury(II) complexes [HgI₂(3-aptt)₂] (1), [Hg(4-aptt)₂] (2) and [Hg(a-mtt)₂]·H₂O (3) were synthesized based on three structurally related ligands: 4-amino-3-(3-pyridyl)-1H-1,2,4-triazole-5-thione (3-Haptt), 4-amino-3-(4-pyridyl)-5-mercapto-1,2,4-triazole (4-Haptt) and 4-amino-3-methyl-1,2,4-triazoline-5-thiadone (a-Hmtt). The structures of complexes 1-3 were determined by single-crystal X-ray diffraction techniques and further characterized by elemental analyses, IR spectra. The results reveal that these three complexes take mononuclear structures. And various weak interactions, including N-H···I and N···H-O H-bondings, N_trz···N_py and π···π stacking, play significant roles in crystal structures, just these weak interactions link the mononuclear units into higher-dimensional supramolecular networks. Their thermal stabilities and the solid state luminescent properties have also been discussed.