Open-framework aluminoborates co-templated by two types of primary amines

A series of open-framework aluminoborates (ABOs), [CH₃NH ₃][(CH₃CH₂)₂NH₂] [Al(B₅O₁₀)] (1), [CH₃CH₂NH ₃][(CH₃CH₂)₂NH₂] [Al(B₅O₁₀)] (2), [CH₃CH₂NH ₃][(CH₃)₂NH₂](H₂O) _0.5[Al(B₅O₁₀)] (3) and [CH₃NH ₃][CH₃CH₂NH₃](H₂O) ₂[Al(B₅O₁₀)] (4) have been made co-templated by two types of primary amines under solvothermal conditions and characterized by elemental analysis, IR, TGA, UV-Vis, powder XRD, single crystal XRD and NLO determination, respectively. These four ABOs display two structural types: 1, 2 and 3 are isostructural and exhibit CrB₄ topology, showing three different layers along three different directions; while 4 contains 8-, 14-ring layers, which are packed along the [001] direction to form a noncentrosymmetric 3D framework with 8-, 14-ring channels, showing second harmonic generation (SHG) response that is about 0.5 times that of KDP (KH₂PO₄). The electronic structure calculations for 1 and 4 also have been performed.