Syntheses and structures of a new 2D layered borate and a novel 3D porous-layered aluminoborate

Two new layered and porous-layered borates ([H₂dap][B₇O₁₁(OH)] (1, dap = 1,2-propanediamine) and [H₃O]K_3.52Na_3.48{Al₂[B₇O₁₃(OH)][B₅O₁₀][B₃O₅]}[CO₃] (2)) have been solvothermally made. 1 features a 2D layer made of the [B₇O₁₃(OH)]^6- cluster, in which H₂dap is located in the windows of the layers. The fundamental building block (FBB) [B₇O₁₃(OH)]^6- cluster in 1 represents a new type of FBB of the hepta-borate family. 2 is a novel aluminoborate with a 3D porous-layered structure formed by three types of oxoboron clusters, [B₇O₁₃(OH)]^6-, [B₅O₁₀]^5- and [B₃O₇]^5-, respectively. The strict alternation of the different oxoboron clusters and AlO₄ tetrahedra leads to the abundant channel systems of the structure. 2 is the first aluminoborate (ABO) containing three types of oxoboron clusters and the first 3D porous-layered ABO with seven types of channels. UV-vis diffuse reflectance spectra reveal that both of them are wide band-gap semiconductors and have potential applications in UV regions.