Syntheses of fluorescent thiocyanate supramolecular compounds with unusual two-dimensional structures

Compound [pipH]2[Co(NCS)4] 1 possesses a two-dimensional layer connected by the combination of N-H⋯N hydrogen bonds and weak S⋯S contacts. Under the same conditions, using nickel salt instead of cobalt salt as a starting material, we obtained a different two-dimensional supramolecular layer [pipH]2[Ni(NCS)4] 2 connected by unusual N-H⋯S hydrogen bonds and weak S⋯S contacts. In order to observe the influence of the dimension of ligand on the self-assembly structure, dabco was used substituting for pip, and only compound [dabcoH]2[Ni(NCS)4] 3 was gained, which constructed two-dimensional, highly wavy network with hourglass-shaped cavities only through N-H⋯S hydrogen bonds.