Syntheses and crystal structures of two new aluminoborates with helical channels

Two new aluminoborates, K2[AlB5O10]·(H2O)4 (1) and [C5H16N2][AlB5O10] (2), have been synthesized under hydrothermal conditions and characterized by elemental analysis, IR, TG analysis, powder and single-crystal X-ray diffractions. Both of the compounds are monoclinic with the lattice constants a = 6.2410(2) Å, b = 13.7188(5) Å, c = 6.9301(4) Å, β = 95.365(3)° and V = 590.75(4) Å3 in the space group P21 for 1 and a = 9.0802(3) Å, b = 11.1131(2) Å, c = 7.9230(5) Å, β = 117.745(3)° and V = 707.58(5) in the space group C2 for 2. These two structures share a similar three-dimensional framework constructed by AlO4 tetrahedra and B5O10 clusters, containing 6, 8-MR helical channels and odd 11-MR channels, in which the guest templates and H2O molecules are located.

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► Syntheses and single-crystal structures of two aluminoborates, K2[AlB5O10]
• (H2O)4 (1) and [C5H16N2][AlB5O10] (2).
► Both structures share a similar three-dimensional framework constructed by the common AlO4 tetrahedra and B5O10 clusters.
► Both structures simultaneously exhibit intersecting 6, 8-MR helical channels and large odd 11-MR channels.