Antitumor activity of 1.3-diketonato zirconium (IV) and hafnium (IV) complexes.

Ten six-coordinate dihalogenobis (1.3-diketonato)zirconium (IV) and hafnium (IV) complexes as well as seven halogenotris(1.3-diketonato) zirconium(IV) and hafnium(IV) species were prepared and characterized by their elemental analysis, IR- and NMR-spectra. Their antitumor activity was tested using the intraperitoneally transplanted Sarcoma 180 tumor system in mice. Cisplatin was used in several doses as positive control compound. Seven complexes were highly active. The ratio of median survival time of treated to untreated control animals ranged up to 3 (T/C = 300%; the experiment was interrupted after that time) for these compounds. Significance according to Kruskal-Wallis test, long-time survivors, and animals which are dead on day 5 and day 30 are given. The possible mechanism of action compared to cisplatin is discussed.