A variety of
gold(III) and
gold(I) derivatives of
2-(2'-pyridyl)benzimidazole (pbiH) were synthesized and fully characterized and their antiproliferative properties evaluated in a representative
ovarian cancer cell line. The complexes include the mononuclear species [(pbi)AuX(2)] (X = Cl, 1; OAc, 2), [(pbiH)AuCl] (3), [(pbiH)Au(PPh(3))][PF(6)] (4-PF(6)), and [(pbi)Au(L)] (L = PPh(3), 5; TPA, 6), and the binuclear
gold(I)/
gold(I) and
gold(I)/
gold(III) derivatives [(PPh(3))(2)Au(2)(μ(2)-pbi)][PF(6)] (10-PF(6)), [ClAu(μ(3)-pbi)AuCl(2)] (7),and [(PPh(3))Au(μ(3)-pbi)AuX(2)][PF(6)] (X = Cl, 8-PF(6); OAc, 9-PF(6)). The molecular structures of 6, 7, and 10-PF(6) were determined by X-ray diffraction analysis. The chemical behavior of these compounds in
solution was analyzed both by cyclic voltammetry in DMF and absorption UV-vis spectroscopy in an aqueous
buffer. Overall, the stability of these
gold compounds was found to be acceptable for the cellular studies. For all complexes, relevant antiproliferative activities in vitro were documented against A2780 human ovarian
carcinoma cells, either resistant or sensitive to
cisplatin, with IC(50) values falling in the low micromolar or even in the nanomolar range. The investigated
gold compounds were found to overcome resistance to
cisplatin to a large degree. Results are interpreted and discussed in the frame of current knowledge on cytotoxic and antitumor
gold compounds.