Newly-Obtained Two Organic-Inorganic Hybrid Compounds Based on Potassium Peroxidomolybdate and Dicarboxypyridinic Acid: Structure Determination, Catalytic Properties, and Cytotoxic Effects of Eight Peroxidomolybdates in Colon and Hepatic Cancer Cells

Two new organic-inorganic hybrid compounds containing dicarboxylic pyridine acids have been obtained and characterized. Both compounds are potassium oxidodiperoxidomolybdates with 2,6-dicarboxylicpyridine acid or 3,5-dicarboxylicpyridine acid moieties, respectively. The chemical formula for the first one is C(14)H(7)K(3)Mo(2)N(2)O(18) denoted as K26dcpa, the second C(7)H(4)K(1)Mo(1)N(1)O(11.5)—K35dcpa. Their crystal structures were determined using single crystal (K26dcpa) or XRPD—X-ray powder diffraction techniques (K35dcpa). The purity of the compounds was confirmed by elemental analysis. Their thermal stability was determined with the use of non-ambient XRPD. In addition, they were examined by IR spectroscopy methods and catalytic activity studies were performed for them. Catalytic tests in the Baeyer–Villiger reaction and biological activity have been performed for eight compounds: K26dcpa, K35dcpa, and six peroxidomolybdates previously obtained by our group. The anti-proliferative activity of peroxidomolybdenum compounds after 24 h of incubation was studied in vitro against three selected human tumor cell lines (SW620, LoVo, HEP G2) and normal human cells (fibroblasts). The data were expressed as IC(50) values. The structure of the investigated oxodiperoxomolybdenum compounds was shown to have influence on the biological activity and catalytic properties. It has been shown that the newly-obtained compound, K35dcpa, is a very efficient catalyst in the Baeyer–Villiger reaction. The best biological activity results were obtained for Na-picO (previously obtained by us), which is a very effective anti-cancer agent towards SW 620 colorectal adenocarcinoma cells.