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)]b>nb> (<b>1b>–<b>3b>) 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 = -CFb>2b>CFb>2b>CFb>3b>; HQ^cy, R = -cyclo-Cb>6b>Hb>11b>; HQ^be, R = -C(H)═C(CHb>3b>)b>2b>). [Ag(Q^R)]b>nb> react with 2-ethylimidazole (2EtimH), 1-methylimidazole (Meim), and triphenylphosphine (PPhb>3b>), affording the mononuclear Ag(Q^fb)(EtimH) (<b>4b>), Ag(Q^cy)(Meim)b>2b> (<b>5b>), Ag(Q^be)(Meim) (<b>6b>), and Ag(Q^R)(PPhb>3b>)b>2b> (<b>7b>–<b>9b>). 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)(PPhb>3b>)b>2b> 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 Ob>2b>-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)(PPhb>3b>)b>2b> (<b>7b>–<b>9b>) seem not to be able to efficiently inhibit the growth of Escherichia coli and Staphylococcus aureus, the polynuclear complexes [Ag(Q^R)]b>nb> (<b>1b>–<b>3b>) and the mononuclear Ag(Q^fb)(EtimH) (<b>4b>), Ag(Q^cy)(Meim)b>2b> (<b>5b>), and Ag(Q^be)(Meim) (<b>6b>) show a high and almost steady in time antibacterial activity, comparable to that of AgNOb>3b>. 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.