Two metal-pipemidic acid complexes modifying Keggin polyoxometalates

Two new organic–inorganic hybrid compounds based on Keggin polyoxometalates (POMs) and the quinolone antibacterial, pipemidic acid (HPPA), {[Cu(PPA)2]2[H3PMo12O40]}·8H2O (1), and {[Zn(PPA)2][H3PMo12O40]}·[HPPA]·3H2O (2) have been synthesized under hydrothermal conditions and structurally characterized. In 1, Keggin POMs combine with two chelate Cu(PPA)2 complexes forming a discrete “seesaw-like” motif, while Keggin POMs combine with the binuclear zinc clusters [Zn2(PPA)4] forming a discrete “dumbbell-like” motif in 2. Antitumor activities in vitro and the interactions with CT-DNA of the compounds have been investigated by MTT experiment and UV spectra, respectively.