Synthesis, crystal structures and urease inhibition of nickel(II), copper(II), zinc(II) and molybdenum(VI) complexes derived from N,n’ -bis(4-bromosalicylidene)-1,3-propanediamine

Three new trinuclear complexes containing either nickel(II), copper(II) or zinc(II), Ni3L2(NO3)2(CH3OH)2·2CH3OH (1), Cu3Br2L2 (2), Zn3L2(NCS)2(CH3OH)2·0.5CH3OH·0.5H2O (3), and a new dioxidomolybdenum(VI) complex, MoO2L (4), have been prepared from the bis-Schiff base N,N'-bis(4-bromosalicylidene)-1,3-propanediamine (H2L) with various metal salts in methanol. The complexes were characterized by elemental analysis, IR and UV–Vis spectra. Molecular structures were confirmed by single crystal X-ray diffraction experiments. The Ni ions in 1 adopt an octahedral coordination environment, bridged by phenolate oxygen and nitrate ligands. The Cu ions in 2 are square pyramidal and square planar, and the Zn ions in 3 are square pyramidal and octahedral. The metal atoms in 2 and 3 are bridged by phenolate oxygen donors. The Mo ion in 4 is octahedral. The Schiff base ligand coordinates to the metal atoms through two phenolate O and two imino N donors. Biological assays revealed that the nickel and copper complexes have effective urease inhibition.