Cationic triruthenium(III) oxo complexes of the type [Ru3O(OAc)6L3]+ containing imidazole, pyrazole, thiazole and oxazole ligands: Synthesis, molecular structure, and cytotoxicity

The cationic complexes [Ru3O(OAc)(6)L-3](+) [1: L = imidazole (imz), 2: L = pyrazole (pyz), 3: L = thiazole (taz), 4: L = oxazole (oxz), 5: L = benzimidazole (biz), 6: L = benzopyrazole (bpz), 7: L = benzothiazole (btz) and 8: L = benzoxazole (boz)] were synthesized by reaction of the precursor [Ru3O(OAc)(6)(MeOH)(3)](+) with the corresponding heterocycle and isolated as the triflate salts. In all complexes, the heterocycle is coordinated to ruthenium by the pi-bonded nitrogen atom. The single-crystal X-ray structure analysis of [4][CF3-SO3] shows the typical triruthenium mu(3)-oxo core, in which the three ruthenium atoms are pairwise bridged by two acetato ligands and N-coordinated by an oxazole ligand. The in vitro anticancer activity of 1-7 was studied with human lung cancer cells A549, the only active complex being the benzothiazole derivative 7 (IC50 = 49 mu M). (C) 2014 Elsevier B.V. All rights reserved.