Hydrothermal syntheses and crystal structures of five complexes with 3,5-dinitrosalicylate and N-donor ligand: Helical chains, 2D network and extended 3D structures

Five complexes with 3,5-dinitrosalicylate (3,5-(NO2)2sal) and N-donor ligand, [Cd{3,5-(NO2)2sal}(phen)(H2O)]n (1), Ni{3,5-(NO2)2sal}(phen)(H2O)2 (2), [Co{3,5-(NO2)2sal}(4,4′-bipy)(H2O)·(H2O)]n (3), [Co{3,5-(NO2)2sal}(phen)]n (4) and [Zn{3,5-(NO2)2sal}(phen)]n (5), have been synthesized by hydrothermal reactions and characterized by single crystal X-ray analysis, where phen = 1,10-phenanthroline and 4,4′-bipy = 4,4′-bipyridine. There are one-dimensional left- and right-handed helical chains in complexes 1, 4 and 5, an extended 3D structure in 2, and a 2D rectangular grid-like network in 3. The C–H···O hydrogen bonds lead to the formation of 3D supramolecular structures in the five title complexes. The fluorescent spectra study show that compounds 1 and 5 exhibit weak fluorescent emission in the solid state at room temperature.