Two Zeolitic Open-Framework Aluminoborates Directed by Similar Zn-Complexes

Two three-dimensional (3D) zeolitic open-framework aluminoborates (ABOs) [Zn(ma)(en)₂][AlB₅O₁₀] (1) and [Zn(ma)(en)₂][AlB₆O₁₁(OH)] (2) (ma = methylamine, en = ethylenediamine) were successfully made under solvothermal conditions, which represent the first examples using similar metal complex (MC) with mixed amines as the structure-directing agents in ABOs. Notice that the central atom in the MC is coordinated by mixed amines is uncommon. However, they exhibit distinctly different structures: 1 crystallizes in a centrosymmetric [Al(B₅O₁₀)]_n^2n- zeolitic framework built by pentaborate (B₅O₁₀) clusters and AlO₄ tetrahedra, exhibiting a 4-connected cag topology, while 2 contains hexaborate (B₆O₁₁(OH)) clusters and AlO₄ groups, further alternately joined to form a noncentrosymmetric [AlB₆O₁₁(OH)]_n^2n- zeolitic framework with 7-/9-, 8-/10-ring helical channels and large 13-ring channels, showing a dia topology. Nonlinear optical (NLO) determination showed that 2 exhibits good second-harmonic generation response of ∼1.9 × KH₂PO₄ and is phase-matchable, combining the short UV cutoff edge, making 2 a potential UV NLO material.