Unusual self-assembled 1D tape of tetramers and water–nitrate clusters trapped in a zinc(II) complex: Synthesis, characterization, luminescence and catalytic properties

Abstract

Unusual tetramers and water–nitrate clusters have been observed in a mononuclear zinc(II) complex of [Zn(4-cpa)(phen)2(H2O)]·(H2O)·(NO3)] (1), (4-Hcpa=4-chlorophenoxyacetic acid, phen=1,10-phenanthroline), which was synthesized under hydrothermal conditions and characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis (TGA), powder X-ray diffraction, UV–vis absorption spectra and single-crystal X-ray diffraction. The crystal structure analysis of 1, reveals that the nitrate anions, water molecules and carboxylate oxygen atoms (O3) pack to form a one-dimensional infinite tape parallel to the c-axis. The uncoordinated carboxylate oxygen atoms (O3) of 4-cpa ligands, water molecules and nitrate anions interact via hydrogen bonds and extend 1 into a water–anion-cation tape, which are finally connected into a 3D supramolecular structure via π⋯π stacking interactions. Excitation (λex=310nm) and luminescence data observed at room temperature show that 1 emits bright blue fluorescence. Moreover, 1 has a remarkable activity for degradation of methyl orange in a photo-assisted Fenton-like process.