Antibacterial action of 4,4'-bipyrazolyl-based silver(I) coordination polymers embedded in PE disks

Inorg Chem. 2012 Sep 17;51(18):9775-88. doi: 10.1021/ic3011635. Epub 2012 Aug 24.

Abstract

Coupling the rigid spacer 4,4'-bipyrazole (H(2)BPZ), in its anionic or neutral form, to different silver(I) salts allowed isolation of the novel coordination polymers [Ag(2)(BPZ)] (1) and [Ag(H(2)BPZ)(X)] (X = NO(3), 2; ClO(4), 3; BF(4), 4; PF(6), 5; CH(3)SO(3), 6; CF(3)SO(3), 7), which were fully characterized by infrared and emission spectroscopies, thermal analysis, and X-ray powder diffraction. The crystal structure of 1 consists of 2-D layers containing 1-D chains of Ag(I) ions bridged by exo-tetradentate bipyrazolato moieties. The crystal structures of the [Ag(H(2)BPZ)(X)] species 2-7 feature 1-D chains of [Ag(H(2)BPZ)] stoichiometry, along which the metal centers are bridged by exo-bidentate bipyrazolyl spacers. Contacts among adjacent chains are mediated by the counterions through nonbonding interactions involving the Ag(I) ions and the pyrazolyl N-H groups. Thermogravimetric analyses disclosed the good thermal stability of these materials, decomposing in the range 200-300 °C. Under UV irradiation at room temperature, all the species showed a yellow-green emission centered in the range 520-522 nm. When embedded into polyethylene disks, 1, 2, and 4-7 demonstrated their activity as topical antibacterial agents against suspensions of E. coli, P. aeruginosa, and S. aureus: complete reduction of the three bacterial strains was achieved in 24 h, reduction of S. aureus reaching ca. 90% in only 2 h. Biocidal action was expressed also by contact susceptibility tests.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Bacterial Agents / chemical synthesis
  • Anti-Bacterial Agents / chemistry
  • Anti-Bacterial Agents / pharmacology*
  • Crystallography, X-Ray
  • Escherichia coli / drug effects*
  • Microbial Sensitivity Tests
  • Models, Molecular
  • Molecular Structure
  • Organometallic Compounds / chemical synthesis
  • Organometallic Compounds / chemistry
  • Organometallic Compounds / pharmacology*
  • Pseudomonas aeruginosa / drug effects*
  • Pyrazoles / chemistry*
  • Silver / chemistry*
  • Staphylococcus aureus / drug effects*

Substances

  • Anti-Bacterial Agents
  • Organometallic Compounds
  • Pyrazoles
  • Silver