Two New Aluminoborates with 3D Porous-Layered Frameworks

Two new aluminoborates, NaKCs[AlB₇O₁₃(OH)]·H₂O (1) and K₄Na₅[AlB₇O₁₃(OH)]₃·5H₂O (2), have been hydro(solvo)thermally made with mixed alkali metal cationic templates. Both 1 and 2 crystallize in the monoclinic space group P2₁/n and contain similar units of [B₇O₁₃(OH)]⁶⁻ cluster and AlO₄ tetrahedra. The [B₇O₁₃(OH)]⁶⁻ cluster is composed of three classical B₃O₃ rings by vertex sharing, of which two of them connect with AlO₄ tetrahedra to constitute monolayers, and one provides an O atom as a bridging unit to link two oppositely orientated monolayers by Al-O bonds to form 3D porous-layered frameworks with 8-MR channels. UV-Vis diffuse reflectance spectra indicate that both 1 and 2 exhibit short deep-UV cutoff edges below 190 nm, revealing that they have potential applications in deep-UV regions.