Lithium(I), Cesium(I), Barium(II) and Cadmium (II) [2-(2,6-dichlorophenylamino)phenyl]acetate (diclofenac) complexes and coordination polymers

Abstract

Two new lithium complexes and three coordination polymers with cesium, barium, and cadmium having deprotonated diclofenac acid (HDFA) ligand are reported. All these non-ionic complexes or the coordination polymers were characterized by single crystal X-ray diffraction, IR and thermal studies. The lithium-diclofenac complexes, [Li(DFA)(H2O)3] and [Li(DFA)(H2O)2(DMF)] were respectively obtained from reaction carried out in aqueous ethanol or dimethylformamide as solvent. Each formed hydrogen bonded 2D-sheets, which were further assembled into 3D-layers by involving edge-on Cl-π interactions. The respective average particle sizes determined by dynamic light scattering of the respective lithium complexes were 648.3 nm and 588.8 nm. The average particle size of the tri-aquated complex dissolved in water was decreased upon addition of dimethylformamide. The cesium coordination polymer [Cs(DFA)(μ-H2O)2]n had two-dimensional sheets formed through dative bonds. The hydrophobic parts of the sheets were projecting outward and two alternative sheets were inter-linked by edge-on chlorine-π interactions (3.391 Å) to provide 3-D supramolecular layered structure. One dimensional barium coordination polymer [Ba(DFA)2(H2O)4]n and a cadmium coordination polymer [{Cd(DMF)4}2+{Cd(DFA)4}2−]n having linear-chain structure were reported. The linear chain of the cadmium coordination polymer was comprised of the coordinatively linked assembly of complex cation [Cd(DMF)4]2+ with anion [Cd(DFA)4]2− located at alternative positions by side-on carboxylate bridges.