Substituted group-directed magnesium(II) coordination compounds based on the derivatives of tetrazole-2-acetic acid

The different substituted group will have a substantial effect on the crystal structures of the resulting compounds. Tetrazole–carboxylate ligands are outstanding blocks for construction of novel coordination architectures. Three derivative ligands of tetrazole-2-acetic acid, H3-pytza, H4-pytza and H3tzpha, where H3-pytza = 5-(3-pyridyl)tetrazole-2-acetic acid, H4-pytza = 5-(4-pyridyl)tetrazole-2-acetic acid and H3tzpha = 1,3,5-tris(tetrazol-5-yl)benzene-N2,N2′,N2″-triacetic acid, have been chosen to be reacted with Mg(NO3)2·6H2O, resulting in the formation of three new compounds, [Mg(H2O)6](3-pytza)2·2H2O (1), [Mg(4-pytza)2(H2O)4] (2) and [Mg3(tzpha)2(H2O)12]·10H2O (3). These compounds were characterized by elemental analysis, IR spectroscopy and single-crystal X-ray diffraction. The X-ray diffraction reveals that compounds 1 and 2 are mononuclear structures, while compound 3 shows a one-dimensional chain. The structures of these compounds are controlled by not only the different 5-substituted group of the tetrazole-2-acetic acid, but also the complementary hydrogen bonds. Furthermore, the luminescence studies show that compounds 1–3 show stronger emission than the corresponding ligands.