Syntheses and crystal structures of two new aluminoborates with helical channels

摘要

Two new aluminoborates, K_2[AlB_5O_(10)]-(H_2O)_4 (1) and [C_5H_(16)N_2][AlB_5O_(10)] (2), have been synthesized under hydrothermal conditions and characterized by elemental analysis, IR, TG analysis, powder and single-crystal X-ray diffractions. Both of the compounds are monoclinic with the lattice constants a = 6.2410(2) A, b = 13.7188(5) A, c = 6.9301(4) A, β = 95.365(3)° and V= 590.75(4) A~3 in the space group P2_1 for 1 and a = 9.0802(3) A, b = 11.1131(2) A, c = 7.9230(5) A, (3=117.745(3)° and V= 707.58(5) in the space group C_2 for 2. These two structures share a similar three-dimensional framework constructed by AlO_4 tetrahedra and B_5O_(10) clusters, containing 6, 8-MR helical channels and odd 11-MR channels, in which the guest templates and H_2O molecules are located.