title: Linkage Isomerism in Silver Acylpyrazolonato Complexes and Correlation with Their Antibacterial Activity.
abstract: Novel silver(I) acylpyrazolonato coordination polymers of formula [Ag(Q(R))]n (1-3) have been synthesized by interaction of silver nitrate with HQ(R) in methanol in the presence of an equivalent quantity of KOH (in general HQ(R) = 1-phenyl-3-methyl-4-RC(═O)-5-pyrazolone, in detail HQ(fb), R = -CF2CF2CF3; HQ(cy), R = -cyclo-C6H11; HQ(be), R = -C(H)═C(CH3)2). [Ag(Q(R))]n react with 2-ethylimidazole (2EtimH), 1-methylimidazole (Meim), and triphenylphosphine (PPh3), affording the mononuclear Ag(Q(fb))(EtimH) (4), Ag(Q(cy))(Meim)2 (5), Ag(Q(be))(Meim) (6), and Ag(Q(R))(PPh3)2 (7-9). All complexes have been analytically and spectroscopically characterized, and for some of them the X-ray crystal structure has been resolved. In particular, the single crystal molecular structure determination of Ag(Q(fb))(EtimH) and Ag(Q(be))(PPh3)2 has confirmed the different coordination modes of the HQ(fb) and HQ(be) acylpyrazolone ligands, the former being bound to the silver(I) ion in a monodentate fashion while the latter in the O2-chelating mode. Density functional theory computations suggest new insights about metal-ligand interactions and the observed linkage isomerism. While phosphine-containing complexes Ag(Q(R))(PPh3)2 (7-9) seem not to be able to efficiently inhibit the growth of Escherichia coli and Staphylococcus aureus, the polynuclear complexes [Ag(Q(R))]n (1-3) and the mononuclear Ag(Q(fb))(EtimH) (4), Ag(Q(cy))(Meim)2 (5), and Ag(Q(be))(Meim) (6) show a high and almost steady in time antibacterial activity, comparable to that of AgNO3. This activity is likely related to the degree of saturation of the silver center and to the presence of different ancillary ligands in the diverse typologies of complexes.
authors.affiliation: ICCOM, CNR 62032 Camerino, Italy.
authors.forename: Fabio
authors.initials: F
authors.lastname: Marchetti
authors.forename: Jessica
authors.initials: J
authors.lastname: Palmucci
authors.affiliation: ICCOM, CNR 62032 Camerino, Italy.
authors.forename: Claudio
authors.initials: C
authors.lastname: Pettinari
authors.affiliation: ICCOM, CNR 62032 Camerino, Italy.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Pettinari
authors.affiliation: School of Pharmacy, Hygienistic, Environmental and Health Sciences Research Centre, University of Camerino , Via Madonna delle Carceri 9, 62032 Camerino (MC), Italy.
authors.forename: Stefania
authors.initials: S
authors.lastname: Scuri
authors.affiliation: School of Pharmacy, Hygienistic, Environmental and Health Sciences Research Centre, University of Camerino , Via Madonna delle Carceri 9, 62032 Camerino (MC), Italy.
authors.forename: Iolanda
authors.initials: I
authors.lastname: Grappasonni
authors.affiliation: School of Pharmacy, Hygienistic, Environmental and Health Sciences Research Centre, University of Camerino , Via Madonna delle Carceri 9, 62032 Camerino (MC), Italy.
authors.forename: Mario
authors.initials: M
authors.lastname: Cocchioni
authors.affiliation: Dipartimento di Scienze, LASCAMM, CR-INSTM Unità della Basilicata and La.M.I. , Via dell'Ateneo Lucano, 10, 85100 Potenza, Italy.
authors.forename: Mario
authors.initials: M
authors.lastname: Amati
authors.affiliation: Dipartimento di Scienze, LASCAMM, CR-INSTM Unità della Basilicata and La.M.I. , Via dell'Ateneo Lucano, 10, 85100 Potenza, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Lelj
authors.affiliation: Centro di Eccellenza CEMIF.CAL-LASCAMM, CR-INSTM (Unità della Calabria, Dipartimento di Chimica e Tecnologie Chimiche), Università della Calabria , I-87030 Arcavacata di Rende (CS), Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Crispini
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000494:pharmacology*; D018360:Crystallography, X-Ray; D007536:Isomerism; D015394:Molecular Structure; D011720:Pyrazoles / Q000737:chemistry*; D012834:Silver / Q000737:chemistry*; D013057:Spectrum Analysis / Q000379:methods
chemical_list: D000900:Anti-Bacterial Agents; D011720:Pyrazoles; D012834:Silver