Synthesis, crystal structures and properties of three new mixed-ligand d10 metal complexes constructed from pyridinecarboxylate and in situ generated amino-tetrazole ligand

Three new metal–organic frameworks, [Zn(atz)(nic)]n(1), [Zn(atz)(isonic)]n·nHisonic(2) and [Cd(atz)(isonic)]n(3) (Hnic=nicotinic acid, Hisonic=isonicotinic acid), have been firstly synthesized by employing mixed-ligand of pyridinecarboxylate with the in situ generated ligand of 5-amino-tetrazolate(atz−), and characterized by elemental analysis, IR spectroscopy, TGA and single crystal X-ray diffraction. The results revealed that 1 presents a two-dimensional (2D) “sql” topological network constructed from the linear chain subunit of Zn(nic)2 and atz− ligand. A remarkable feature of 2 is a 2-fold interpenetrated diamondoid network with free Hisonic molecules locating in the channels formed by the zigzag chain subunits of Zn(isonic)2. Complex 3 is a 3D non-interpenetrated pillared framework constructed from the double chain subunits of Cd–COO−–Cd. It possesses a rarely observed (4,6)-connected “fsc” topology. The thermal stabilities and fluorescent properties of the complexes were investigated. All of these complexes exhibited intense fluorescent emissions in the solid state at room temperature.