Synthesis, Characterization, and Amine Intercalation Behavior of Zirconium N-(Phosphonomethyl)iminodiacetic Acid Layered Compounds

New types of zirconium layered compounds containing the N-(phosphonomethyl)iminodiacetic acid group (PMIDAH2) have been synthesized and characterized. A mixed phosphate/phosphonate compound, Zr2(PO4)(O3PCH2N{CH2COOH}2)(O3PCH2N{CH2COOHCH2COO-})(H2O)2 (I) was obtained when a mixture of phosphoric acid and diacetatoiminophosphonic acid (H2PMIDAH2) solution in the ratio of 1:1 was heated with the zirconyl chloride in the presence of HF. The layer structure of this compound is different from that of any known layered zirconium phosphonate compounds. The bridging of metal atoms by the phosphate groups within the layer is similar to that found in γ-ZrP, while the mode of phosphonate binding is similar to that found for α-ZrP. When the above reaction was carried out with additional phosphoric acid, a similar layered structure but with composition Zr2(PO4)(O3PC5H7O4N)(O3PC5H8O4N)x(HPO4)1-x(H2O)2 (II) was obtained. In this compound some of the phosphonate groups are replaced by the HPO42- groups. When the ratio of ...