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Several oxidoborates, self-assembled from B(OH)₃ and templated by cationic Ni^(II) coordination compounds, were synthesized by crystallization from aqueous solution. These include the ionic compounds <i>trans</i>-[Ni(NH₃)₄(H₂O)₂][B₄O₅(OH)₄]^.H₂O (<b>1</b>), s-[Ni(dien)₂][B₅O₆(OH)₄]₂ (dien = <i>N</i>-(2-aminoethyl)-1,2-ethanediamine (<b>2</b>), <i>trans</i>-[Ni(dmen)₂(H₂O)₂] [B₅O₆(OH)₄]₂^.2H₂O (dmen = <i>N,N</i>-dimethyl-1,2-diaminoethane) (<b>3</b>), [Ni(HEen)₂][B₅O₆(OH)₄]₂ (HEen = <i>N</i>-(2-hydroxyethyl)-1,2-diaminoethane) (<b>4</b>), [Ni(AEN)][B₅O₆(OH)₄]^.H₂O (AEN = 1-(3-azapropyl) -2,4-dimethyl-1,5,8-triazaocta-2,4-dienato(1-)) (<b>5</b>), <i>trans</i>-[Ni(dach)₂(H₂O)₂][Ni(dach)₂] [B₇O₉(OH)₅]₂^.4H₂O (dach = 1,2-diaminocyclohexane) (<b>6</b>), and the neutral species <i>trans</i>-[Ni(en)(H₂O)₂{B₆O₇(OH)₆}]^.H₂O (<b>7</b>) (en = 1,2-diaminoethane), and [Ni(dmen)(H₂O){B₆O₇(OH)₆}]^.5H₂O (<b>8</b>). Compounds <b>1–8</b> were characterized by single-crystal XRD studies and by IR spectroscopy and <b>2</b>, <b>4–7</b> were also characterized by thermal (TGA/DSC) methods and powder XDR studies. The solid-state structures of all compounds show extensive stabilizing H-bond interactions, important for their formation, and also display a range of gross structural features: <b>1</b> has an insular tetraborate(2-) anion, <b>2–5</b> have insular pentaborate(1-) anions, <b>6</b> has an insular heptaborate(2-) anion (‘O⁺’ isomer), whilst <b>7</b> and <b>8</b> have hexaborate(2-) anions directly coordinated to their Ni^(II) centers, as bidentate or tridentate ligands, respectively. The Ni^(II) centers are either octahedral (<b>1–4</b>, <b>7</b>, <b>8</b>) or square-planar (<b>5</b>), and compound <b>6</b> has both octahedral and square-planar metal geometries present within the structure as a double salt. Magnetic susceptibility measurements were undertaken on all compounds.