Abstract: Three monoFe(Ⅲ)substituted Keggintype phosphotungstates with different organic ammonium cations were systhesized: [JP2]［CTA］₄PW₁₁Fe(H₂O)O₃₉ (CTAFe), ［TEA］₄PW₁₁Fe(H₂O)O₃₉ (TEAFe) and ［TMA］₄PW₁₁Fe(H₂O)O₃₉ (TMAFe) (CTA=cetyl trimethyl ammonium bromide, TEA=tetraethyl ammonium bromide, TMA=tetramethyl ammonium bromide). The structure and morphology of three phosphotungstates were characterized by infrared spectroscopy (IR), UV\|visible spectroscopy (UV\|Vis)， Xray diffraction (XRD) and scanning electron microscopy (SEM). The inhibitory effect of three phosphotungstates on the growth of human colorectal carcinoma HCT116, HT29 cells and rat colorectal carcinoma CT26 cells was studied by MTT assay. The results show that the phosphotungstates with different organic ammonium cations still keep Keggintype structure. But the cations affect the morphology. Longer carbon chain of organic ammonium cations makes crystallinity decrease, no clear crystal morphology of CTAFe. TEAFe and TMAFe have no inhibition on HCT116, HT29 and CT26 cell proliferation, but CTAFe can inhibit these three tumor cells proliferation, showing dosedependent. The IC₅₀ value for CT26 and HCT116 cell was 0.038,0.08 mg/mL, respectively. So longer carbon chain of organic ammonium cation makes Keggintype phosphotungstates inhibit tumor cell growth stronger.

Key words: organic ammonium, phosphotungstate, antitumor, Keggintype