Copper(I) halides and palladium(II) chloride complexes of 4-thioxo[1,3,5]oxadiazocines: synthesis, structure and antibacterial activity

The copper(I) halides and palladium(II) chloride complexes with tricyclic Monastrol analogs containing oxadiazocine ring have been synthesized and studied. The structures of the complexes were investigated with IR, NMR and UV spectra. Two complexes, [Cu(L1)2Cl] and [Pd(L1)2Cl2], were structurally characterized by X-ray single-crystal and powder diffraction respectively. All the obtained coordination compounds were mononuclear. The ligands were coordinated with copper(I) and palladium(II) only via soft sulfur atoms of thiocarbamide fragments, while harder nitrogen and oxygen atoms remained uncoordinated. Palladium center was coordinated by two Cl ions and two S atoms from two 4-thioxo[1,3,5]oxadiazocine ligands in a distorted square-planar geometry. Copper(I) formed trigonal planar geometry. The complexes demonstrated significant antibacterial activity towards Escherichia coli K12 TG 1 bacterial strain in contrast to the free ligands which didn’t show any noticeable activity.