Syntheses and Crystal Structures of Two New Pentaborates Templated by Transition-Metal Complexes

Two new pentaborates [M(dap)(3)][B5O6(OH)(4)](2)center dot H2O (M = Co (1) and Ni (2); dap = 1,2-diaminopropane) have been hydrothermally synthesized. Both structures were determined by single crystal X-ray diffraction and further characterized by elemental analysis, FT-IR, thermogravimetric analysis and photoluminescence spectroscopy. Two compounds are isostructural and consist of isolated pentaborate [B5O6(OH)(4)](-) anions and [M(dap)(3)](2+) complex cations. The anionic [B5O6(OH)(4)](-) groups are linked by extensive hydrogen bonds to form a 3-D supramolecular framework with large channels, in which the transition-metal complex templates are located. The luminescent properties of 1 and 2 were studied, and blue luminescence occurs with an emission maximum at 405 and 408 nm upon excitation at 332 and 328 nm respectively. Crystal data: 1, monoclinic, space group P2(1)/c (No. 14), a = 9.7159(5) , b = 29.3372(19) , c = 11.5121(6) , beta = 103.286(5)A degrees, V = 3193.6(3) (3), Z = 4; 2, monoclinic, space group P2(1)/c, a = 9.7264(4) , b = 29.3810(16) , c = 11.5185(6) , beta = 103.249(4)A degrees, V = 3204.0(3) (3), Z = 4.