Synthesis and crystal structures of zinc complexes derived from N,N'-bis (4-bromosalicylidene)-1,3-propanediamine with antimicrobial activity

A series of new zinc(II) complexes, [Zn2Cl2L(MeOH)2] (1), [Zn4Cl2L2(N3)2] (2), [Zn4Br2L2(N3)2] (3) and [Zn4I2L2(N(CN)2)2] (4), where L is the dianionic form of N,N'-bis(4-bromosalicylidene)-1,3-propanediamine, have been synthesized and structurally characterized by elemental analysis, infrared spectra, as well as single crystal X-ray diffraction. X-ray analysis indicates that the Zn atoms in the dinuclear complex 1 are in octahedral and tetrahedral coordination, while in the tetranuclear complexes 2, 3 and 4 are in square pyramidal and tetrahedral coordination. In vitro bacterial viability revealed that the complexes have effective antimicrobial activities against B. subtilis, S. aureus, E. coli and P. fluorescens, while weak activities against the fungal strains C. albicans and A. niger.