Synthesis, crystal structure, spectroscopic properties, and antimicrobial studies of a zinc(II) complex of p-coumaric acid

Abstract

The synthesis of the zinc(II) complex of p-coumaric acid is described. The chemical formula of the complex as obtained from the single-crystal X-ray analysis is [Zn₄(C₉H₇O₃)₈(H₂O)₆]·4(H₂O). The compound crystallizes in the triclinic space group P-1 with one molecule in the unit cell. There are two crystallographically independent Zn(II) cations in the structure. Zn1 is six-coordinate to three different carboxylate oxygens and three waters in a distorted octahedral geometry, whereas Zn2 ions are connected to four oxygens from four p-coumarate anions resulting in tetrahedral geometry. Adjacent cations are connected by bridging carboxylates to form centrosymmetric tetranuclear aggregates. Adjacent molecules are connected by a net of strong O–HO hydrogen bonds into a 3D supramolecular framework with 1D open channels filled with water molecules. The zinc complex was characterized by infrared spectroscopy and ¹H and ¹³C NMR spectra. The antimicrobial activities of zinc p-coumarate toward Bacillus subtilis, Candida albicans, Pseudomonas aeruginosa, Proteus vulgaris, and Staphylococcus aureus were tested.

Keywords:

• Zinc(II) complex of p-coumaric acid
• Synthesis
• X-ray crystallography
• Spectroscopy
• Antimicrobial activity

Acknowledgment

Scientific work was financed from the budget for science in 2010–2013 as a research project of Ministry of Science and Higher Education, Poland, no. N N305 384538. The authors would like to thank prof. Izabela Święcicka for the opportunity of microbiological measurements that were carried out in the Department of Microbiology, Institute of Biology, University of Bialystok, Poland.