Effect of pH on the self-assembly of three Cd(II) coordination compounds containing 5-(4-pyridyl)tetrazole: syntheses, structures, and properties

Abstract

Hydrothermal reactions of CdSO4, 4-cyanopyridine, and sodium azide yield three metal coordination compounds via controlling the pH, [Cd2(4-ptz)(SO4)(OH)(H2O)2](H2O) (1) [Cd2(4-ptz)(SO4)(OH)(H2O)]n (2), and known [Cd2(4-ptz)2(H2O)4](H2O)2 (3) (4-ptz = 5-(4-pyridyl)tetrazole). The in situ [2 + 3] cycloaddition reaction of nitrile and azide in the presence of Cd(II) produces the multidentate 4-ptz in these compounds. X-ray diffraction results indicate that metal centers in 1 are linked by 4-ptz–, , and OH− in their respective μ5-, μ2-, μ3-bridging modes, forming a 3-D coordination polymer. For 2, although the same raw materials are used, the component anions are linked to Cd(II) centers in completely different ways, i.e. for 4-ptz− in μ3−, in μ5-, and OH− in μ3-bridging modes, forming another 3-D coordination network. Thermal stabilities and photoluminescent properties of 1 and 2 have also been investigated.