Synthesis and crystal structures of the first cadmium complexes of 3,5,6-tris(2-pyridyl)-1,2,4-triazine ligand

Three new cadmium(II) complexes, [Cd2(TPT)2(SCN)4]·H2O (1), [Cd(TPT)I2] (2) and [Cd(TPT)Br2] (3) (“TPT” is the abbreviation of 3,5,6-tris(2-pyridyl)-1,2,4-triazine), have been synthesized and characterized by elemental analysis, IR, 1H NMR spectroscopy, and studied by thermal gravimetric as well as X-ray single crystal diffraction. Two anions of four thiocyanate anions bridge two CdII ions to form a dinuclear complex, 1, and iodide and bromide ions produce two halide-coordinated [Cd(TPT)X2] complexes (X = I for 2 and Br for 3). Cadmium(II) in 1 is six coordinate, CdN4S2 and in 2 and 3 is five coordinate, CdN3I2 and CdN3Br2. The supramolecular features in these complexes are guided/controlled by N⋯O hydrogen bonding (in 1) and weak directional intermolecular CH⋯N, Cg⋯I, CH⋯Br and π–π interactions.