Aluminoborates with Open Frameworks: Syntheses, Structures, and Properties.

Five aluminoborates Al[B5O10]∙H2dab∙2H2O (1), [Al(B4O9)(BO)] ∙ H2en (2), [Al(B4O9)(BO)]∙H2dap (3), K2Al[B5O10]∙4H2O (4), and (NH4)2Al[B5O10] ∙ 4H2O (5) have been synthesized under hydrothermal conditions and characterized by means of elemental analysis, IR, TG analysis, MAS NMR, UV-vis and fluorescence spectroscopy, powder X-ray diffraction, single-crystal X-ray diffraction, and NLO determination. The structure 1 comprises of A1O4 tetrahedra and B5O10 clusters and contains 12-, 11-, and 8-MR 3D-intersecting channels with a CrB4 topological net. Structures 2 and 3 are both constructed from the same AlB5O13 clusters and exhibit a six-connected framework with 41263 topology. Structures 4 and 5 are isomorphous and are composed of AlO4 tetrahedra and B5O10 clusters that possess odd 11-MR channels and 8-MR helical channels. Structures 2-5 crystallized in an acentric structure and presented good SHG properties. UV-vis spectral investigation indicates that they are wide-band-gap semiconductors. The electronic structure calculations for the compounds also have been performed. [ABSTRACT FROM AUTHOR]