New complexes of Zn(II) with the anti-inflammatory non-steroidal drug, ibuprofen and nitrogen donor ligands. Synthesis, characterization and biological activity

<p>Complexes of [Zn(ibup)₂(4,4′-bipy)]_n <b>1</b>, [Zn(ibup)₂(phen)] <b>2</b>, [Zn(ibup)₂(2,9-dmphen)] <b>3</b>, [Zn(ibup)₂(1,2-dmimidazole)₂] <b>4</b>, and [Zn(ibup)₂(2-am-6-picoline)₂] <b>5</b> (ibu = ibuprofen, 4,4′-bipy = 4,4′-bipypyridine, phen = 1,10-phenanthroline, 2,9-dmephen = 2,9-dimethyl-1,10-phenanthroline, 1,2-dmimidazole = 1,2-dimethylimidazole, and 2-am-6-picoline = 2-amino-6-picoline) were prepared and characterized. The crystal structure of <b>1</b> was determined by single-crystal X-ray diffraction. The <i>in vitro</i> anti-bacterial activities for the complexes against Gram-positive (<i>Micrococcus luteus</i>, <i>Staphylococcus aureus</i> and <i>Bacillus subtilis</i>) and Gram-negative (<i>Escherichia coli</i>, <i>Klebsiella pneumonia</i> and <i>Proteus mirabilis</i>) bacteria were done using the agar well-diffusion method. Complexes <b>1</b>–<b>3</b> showed anti-bacterial activity against Gram-positive bacteria, while <b>4</b> and <b>5</b> did not exhibit anti-bacterial activity. Complexes <b>2</b> and <b>3</b> were selected for further studies. Complexation of zinc-ibuprofen with phen as in <b>2</b> decreased the anti-bacterial activity against most of the bacteria used. The complexation in <b>3</b> decreased the anti-bacterial activity in Gram-positive bacteria but for Gram-negative bacteria, the overall anti-bacterial activity of uncoordinated 2,9-dmphen was enhanced upon coordination with zinc ibuprofen.