The introduction of antibacterial drug pipemidic acid into the POM field: Syntheses, characterization and antitumor activity

Two new compounds based on polyoxometalates (POMs) and the quinolone antibacterial drug pipemidic acid (HPPA), {[Ni(PPA)(2)]H-4[SiW12O40]}center dot HPPA center dot 3H(2)O (1), and {[Zn(PPA)(2)](2)H-4[SiW12O40]}center dot 3H(2)O (2), have been synthesized under hydrothermal conditions and structurally characterized by routine technique. Single-crystal X-Ray diffraction analysis shows that compound 1 is constructed by Keggin clusters grafted by binuclear nickel clusters, isolated HPPA and water molecules, while compound 2 consists of Keggin clusters grafted by binuclear zinc clusters and water molecules. Due to the selection of different transition metal (TM) ions, compounds 1 and 2 exhibit different structures and antitumor activities. Compound 1 possesses OD structure and shows no antitumor activities. However, compound 2 possesses 1D structure and exhibits higher antitumor activities than its parent compound. The results show that introduction of different TM-PPA moieties onto the polyoxoanion surface can affect not only the final structures but also their antitumor activities. (C) 2011 Elsevier Masson SAS. All rights reserved.