Synthesis, characterization and antimicrobial activity of Co(II), Zn(II) and Cd(II) complexes with N-benzyloxycarbonyl-S-phenylalanine

Abstract In this paper the first complexes of M 2+ ions (M 2+  = Zn 2+ , Cd 2+ and Co 2+ ) with N -benzyloxycarbonyl- S -phenylalaninato ligand ( 1 – 3 ) are described. The new complexes were characterized by means of elemental analysis, IR and UV–vis spectroscopy, molar conductivity measurements and 1 H, 13 C and 15 N NMR spectroscopy (1D and 2D). The Co(II) complex adopts an octahedral geometry, and the Zn(II) and Cd(II) complexes adopt a tetrahedral one. For the first time, the antimicrobial activity of N -benzyloxycarbonyl- S -phenylalaninato ligand ( N -Boc- S -phe) and the complexes 1 – 3 was investigated against Gram-positive: Micrococcus luteus, Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis and Bacillus subtilis and Gram-negative bacteria: Escherichia coli , Klebsiella pneumoniae , Pseudomonas aeruginosa and two strains of the yeast Candida albicans . It was shown that the complexes were effective against most strains. The best activity was detected against the yeast C. albicans .