Hydrothermal synthesis, crystal structure and spectroscopic properties of a novel 3D chromium(III) complex

The hydrothermal synthesis of CrCl3·6H2O, NaOH, 2,6-dipicolinic acid (H2dpa), salicylic acid (HSAL) in water and ethanol at 140 °C for 5 days yields a novel 3D coordination polymer NaCr(C7H3O4N)2(H2O)2 (1). In the complex, each Cr center is in a distorted octahedral environment, and coordinates to two nearly perpendicular dpa anions, which act as tridentate ligands. Na(I) is in a compact sixfold coordination with three non-coordination carbonyl oxygen atoms of neighboring asymmetric units, a carboxylate oxygen atom shares coordination with Cr(III) and two aqueous. Two adjacent asymmetric units are linked together through Na–O and a set of intermolecular hydrogen bonds, which generates the finally 3D supermolecular network structure.