Three new aluminoborates: from 1D tube to 3D framework.

Three new aluminoborates (ABOs) KCs[Al{B 5 O 9 (OH)}{BO(OH) 2 } (1), K 0.5 Cs[Al{B 5 O 10 } 1/2 {BO 2 (OH)}] (2), and Cs 1.5 [Al{B 5 O 10 } 1/2 {BO 2 (OH)}] (3) have been made under solvothermal conditions. 1 features a 1D tube constructed by the alternation of [B 5 O 9 (OH)] 4- clusters and AlO 4 units, onto which the [BO(OH) 2 ] - triangles are grafted. To further construct higher dimensional structures based on the structure 1, solvents were adjusted for high basicity, resulting in the formations of the 3D ABO frameworks 2 and 3. 2 and 3 are isostructural and built from [B 5 O 10 ] 5- clusters, AlO 4 tetrahedra and [BO 2 (OH)] 2- triangles, in which [B 5 O 10 ] 5- clusters are bridged by AlO 4 tetrahedra to produce a 2D ABO layer with 14-membered ring (MR) windows, and the [BO 2 (OH)] 2- triangles act as the linkers to bridge the adjacent ABO layers to form 3D ABO frameworks containing eight types of channels. UV-vis diffuse reflectance spectra indicate that 1, 2, and 3 have potential applications in deep ultraviolet (DUV) regions.