Hexaborate(2-) and Dodecaborate(6-) Anions as Ligands to Zinc(II) Centres: Self-Assembly and Single-Crystal XRD Characterization of [Zn{O-3-B6O7(OH)(6)}(N-3-dien)]center dot 0.5H(2)O (dien = NH(CH2-CH2NH2)(2)), (NH4)(2)[Zn{O-2-B6O7(OH)(6)}(2) (H2O)(2)]center dot 2H(2)O and (1,3-pnH(2))(3)[(N-1-H3N{CH2}(3)NH2) Zn{O-3-B12O18(OH)(6)}](2)center dot 14H(2)O (1,3-pn = 1,3-diaminopropane)

Two zinc(II) hexaborate(2-) complexes, [Zn{3O-B6O7(OH)6}(3N-dien)].0.5H2O (dien = NH(CH2CH2NH2)2) (1) and (NH4)2[Zn{2O-B6O7(OH)6}2(H2O)2].2H2O (2), and a zinc(II) dodecaborate(6-) complex, (1,3-pnH2)3[(1N-H3N{CH2}3NH2)Zn{3O-B12O18(OH)6}]2.14H2O (1,3-pn = 1,3-diaminopropane) (3), have been synthesized and characterized by single-crystal XRD studies. The complexes crystallized, through self-assembly processes, from aqueous solutions containing 10:1 ratios of B(OH)3 and appropriate Zn(II) amine complex: [Zn(dien)2](OH)2, [Zn(NH3)4](OH)2, and [Zn(pn)3](OH)2. The hexaborate(2-) anions in 1 and 2 are coordinated to octahedral Zn(II) centres as tridentate (1) or bidentate ligands (2) and the dodecaborate(6-) ligand in 3 is tridentate to a tetrahedral Zn(II) centre.