title: Antibacterial action of 4,4'-bipyrazolyl-based silver(I) coordination polymers embedded in PE disks.
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.
authors.affiliation: Scuola di Scienze del Farmaco e dei Prodotti della Salute, Divisione di Chimica, Università degli Studi di Camerino, Via S. Agostino 1, 62032 Camerino (MC), Italy.
authors.forename: Aurel
authors.initials: A
authors.lastname: Tăbăcaru
authors.forename: Claudio
authors.initials: C
authors.lastname: Pettinari
authors.forename: Fabio
authors.initials: F
authors.lastname: Marchetti
authors.forename: Corrado
authors.initials: C
authors.lastname: di Nicola
authors.forename: Konstantin V
authors.initials: KV
authors.lastname: Domasevitch
authors.forename: Simona
authors.initials: S
authors.lastname: Galli
authors.forename: Norberto
authors.initials: N
authors.lastname: Masciocchi
authors.forename: Stefania
authors.initials: S
authors.lastname: Scuri
authors.forename: Iolanda
authors.initials: I
authors.lastname: Grappasonni
authors.forename: Mario
authors.initials: M
authors.lastname: Cocchioni
mesh_terms: D000900:Anti-Bacterial Agents / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D018360:Crystallography, X-Ray; D004926:Escherichia coli / Q000187:drug effects*; D008826:Microbial Sensitivity Tests; D008958:Models, Molecular; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D011550:Pseudomonas aeruginosa / Q000187:drug effects*; D011720:Pyrazoles / Q000737:chemistry*; D012834:Silver / Q000737:chemistry*; D013211:Staphylococcus aureus / Q000187:drug effects*
chemical_list: D000900:Anti-Bacterial Agents; D009942:Organometallic Compounds; D011720:Pyrazoles; D012834:Silver