Ladders,rings and cubes as structural motifs in three new zinc(II) azide complexes: Synthesis,spectral and structural characterization

Three new zinc(II) azide complexes, namely {Zn₂(N₃)₄(py-tetrazole)₂](py-tetrazole)}_n (1), {Zn₂(N₃)₄(3-OHpy)] · 2H₂O}_n (2) and Zn(N₃)₂(pym)]_n (3), where py-tetrazole = tetrazolo1,5-a]pyridine, 3-OHpy = 3-hydroxypyridine and pym = pyrimidine, have been synthesized by the hydrothermal methods and structurally characterized. The ligand py-tetrazole was obtained through the interaction of 2-chloropyridine with the azide ion under hydrothermal condition. The structure of 1 consists of a ladder-like arrangement of 1D double chain zinc(II) azide. In the coordination chain, each zinc atom binds di-EO azide bridges connecting another zinc atom in opposite chain, and two EO bridges, one on each side, and the fifth position is occupied by a N atom of py-tetrazole ligand. The structure of 2 features 2D sheets composed of tetranuclear zinc(II) ring and octanuclear zinc(II) ring interconnected by EO azide bridges. The 2D carrying into 3D supramolecular network by the help of several hydrogen bonding interactions. The 3-OHpy molecule acts in the tautomeric keto-form as O,O-bidentate bridging ligand. Complex 3 features distorted octahedral geometry around each zinc center, N,N′-bidentate pyrimidine ligand and EE azido bridges leading to 3D network structure. The IR spectra are measured and discussed. Complex 2 only exhibits photoluminescence properties whereas the other two complexes do not luminesce at room temperature.