Synthesis, structure, and solid-state transformation studies of phosphonoacetate based hybrid compounds of uranium and thorium.

Three new phosphonoacetate hybrid frameworks based on the actinide elements uranium and thorium have been synthesized. The compounds [C(4)N(2)H(14)][(UO(2))(2)(O(3)PCH(2)COO)(2)] x H(2)O, I, [C(4)N(2)H(14)][(UO(2))(2)(C(2)O(4))(O(3)PCH(2)COOH)(2)], II, and Th(H(2)O)(2)(O(3)PCH(2)COO)(C(2)O(4))(0.5) x H(2)O, III, are built up from the connectivity between the metal polyhedra and the phosphonoacetate/oxalate units. Compound II has been prepared using a solvent-free approach, by a solid state reaction at 150 degrees C. It has been shown that II can also be prepared through a room temperature mechanochemical (grinding) route. The layer arrangement in III closely resembles to that observed in I. The compounds have been characterized by powder X-ray diffraction, IR spectroscopy, thermogravimetric analysis, and fluorescence studies.