Linkage Isomerism in Silver Acylpyrazolonato Complexes and Correlation with Their Antibacterial Activity

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• 作者：Fabio Marchetti ; Jessica Palmucci ; Claudio Pettinari ; Riccardo Pettinari ; Stefania Scuri ; Iolanda Grappasonni ; Mario Cocchioni ; Mario Amati ; Francesco Lelj ; Alessandra Crispini
• 刊名：Inorganic Chemistry
• 出版年：2016
• 出版时间：June 6, 2016
• 年：2016
• 卷：55
• 期：11
• 页码：5453-5466
• 全文大小：706K
• 年卷期：0
• ISSN：1520-510X

文摘

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.