Expanding monomeric pyrophosphate complexes beyond platinum.

Four new monomeric pyrophosphate complexes, namely [Co(phen)(2)(H(2)P(2)O(7))] x 4 H(2)O (1 x 4 H(2)O), [Ni(phen)(2)(H(2)P(2)O(7))] x 8 H(2)O (2 x 8 H(2)O), [Cu(phen)(H(2)O)(H(2)P(2)O(7))] (3) and {[Cu(phen)(H(2)O)(P(2)O(7))][Na(2)(H(2)O)(8)]} x 6 H(2)O (4 x 14 H(2)O) have been isolated and structurally characterized. The impact of pH and stoichiometry in obtaining 1-4 is described. These complexes have been tested against the adriamycin-resistant ovarian cancer cell line A2780/AD, revealing highly significant (nM) IC(50) values, compared to microM IC(50) values for cisplatin controls.