The synthesis and crystal structure of UiO-19; an organically templated layered titanium phosphate with the ULM-11 topology

摘要

An organically templated layered titanium phosphate, [TiOPO4](-)[NH3(CH2)(2)NH2](+), has been synthesised under hydrothermal conditions. The crystal structure was determined from single-crystal X-ray diffraction. The layers of the two-dimensional structure consist of infinite corner-sharing chains of TiO5N octahedra cross linked by PO4 tetrahedra. The bonds to oxygen along the chain of titanium octahedra alternate between a short bond (1.719(1) Angstrom) and a long bond (2.150(1) Angstrom). One nitrogen of the diamine is directly coordinated to titanium while the other participates in hydrogen bonding to the subsequent anionic layer. The presence of Ti-IV in the compound is consistent with bond valence analysis, the observation of diamagnetic susceptibility and sharp signals in the solid state P-31 NMR measurements. The compound is isostructural to the ULM-11 type of Fe-, Al-, V-fluorophoshates and identical to a titanium phosphate which had been assumed to contain Ti-III. [References: 32]