The syntheses and characterizations of molybdenum(VI) complexes with catechol and 2,3-dihydroxynaphthalene, and the structure-effect relationship in their in vitro anticancer activities.

The reactions of (NH(4))(2)Mo(2)O(7)·2H(2)O with polyhydroxy phenols (catechol or 2,3-dihydroxynaphthalene) and ethylenediamine (en), trimethylenediamine (tn), 1,2-propanediamine (pn), triethylamine (Et(3)N) respectively, in the mixed-solvent of MeCN-EtOH-amine, have resulted in five molybdenum(VI) complexes, (enH(2))[Mo(VI)O(3)(cat)(en)] (1), (tnH(2))[Mo(VI)O(3)(cat)(tn)] (2), (enH)(2)[Mo(VI)O(2)(cat)(2)](en)(0.5) (3), (pnH(2))(2)[Mo(VI)O(2)(cat)(2)] (4) and (HNEt(3))(2)[Mo(VI)O(2)(C(10)H(8)O(2))(2)] (5), of which the structural features were investigated by X-ray diffraction. MTT assay tests indicated that their inhibition ratios against human cancer cells decreased in the order: (1) ≈ (2) > (3) ≈ (4) > (5), i.