Syntheses and Crystal Structures of Three Organically Templated Gallium Phosphates.

Three open-framework gallium phosphates [C₆H₁₆N₂][Ga(HPO₄)(PO₄)] (1), {H[C₆H₁₆N₂]₂[Ga₇(OH)₂(PO₄)₈]} (2), and {H[C₄H₁₂N₂]₂[Ga₇(OH)₂(PO₄)₈]·2H₂O} (3) were solvothermally synthesized in the presence of 2,6-dimethylpyrazine, N-ethylpiperazine, and piperazine as templates, respectively. Compound 1 possesses an infinite one-dimensional chain structure connected by hydrogen-bond interactions to generate a 3D supramolecular framework. Compounds 2 and 3 show similar inorganic framework structures, which may be viewed as the assembly of a secondary building unit (SBU), Ga₆P₈ containing two GaO₄, two GaO₅, two GaO₆ as well as eight PO₄ groups. The SBUs are linked with each other by vertexsharing oxygen atoms to form 2D sheets, which are further connected by GaO₄ tetrahedra to result in the final 3D open-framework with leftand right-handed helical chains. In these materials, the well-ordered organic species reside in the voids of structures and interact with the framework by way of hydrogen bonds. [ABSTRACT FROM AUTHOR]