Transition-metal complexes with oxidoborates. Synthesis and XRD characterization of [(H3NCH2CH2NH2)Zn{κ3O,O′,O′′-B12O18(OH)6-κ1O′′′}Zn(en)(NH2CH2CH2NH3)]·8H2O (en=1,2-diaminoethane): a neutral bimetallic zwiterionic polyborate system containing the ‘isolated’ dodecaborate(6−) anion

The title compound, [(H3NCH2CH2NH2)Zn{κ3O,O′,O′′-B12O18(OH)6-κ1O′′′}Zn(en)(NH2CH2CH2NH3)]·8H2O (en=1,2-diaminoethane) (1), was prepared as a crystalline solid in moderate yield from the reaction of B(OH)3 with [Zn(en)3][OH]2 in aqueous solution (15:1) ratio. The structure contains a neutral bimetallic complex comprised of a unusual dodecaborate(6-) anion ligating two [H3NCH2CH2NH2Zn(en)n]3+ centers in a monodentate (n=1) or tridentate (n=0) manner.</p

Synthesis and characterization of polyborates templated by cationic copper(II) complexes: structural (XRD), spectroscopic, thermal (TGA/DSC) and magnetic properties

Several polyborate containing species templated by cationic copper(II) coordination compounds have been synthesized. The ionic species [Cu(en)2][B5O6(OH)4]2·2H2O (en = 1,2-diaminoethane) (1), [Cu(dmen)2(H2O)][B5O6(OH)4]2·3H2O (dmen = N,N-dimethyl-1,2-diaminoethane) (2), [Cu(pn)2{B5O6(OH)4}][B5O6(OH)4]·4H2O (pn = 1,2-diaminopropane) (3), [Cu(dach)2(H2O)2][Cu(dach)2][B7O9(OH)5]2·4H2O (dach = 1,2-diaminocyclohexane) (4), and the neutral species [Cu(dmen){B6O7(OH)6}]·4H2O (5) and [Cu(tmeda){B6O7(OH)6}]·6H2O (tmeda = N,N,N′,N′-tetramethyl-1,2-diaminoethane) (6) have been synthesized in aqueous solution and characterized by spectroscopic and thermal (TGA/DSC) methods. The previously prepared compound [Cu(en)2][B4O5(OH)4]2·2B(OH)3 (7) has also been prepared by an alternative route. Compounds 1–6 have been further characterized by single-crystal XRD studies. The new compounds show extensive H-bond interactions and display a range of structural features: 1–3 have isolated pentaborate(1-) anions whilst 4 possesses an isolated heptaborate(2-) anion. In addition, 3 has a pentaborate(1-) and 5 and 6 have hexaborate(2-) anions directly coordinated to their copper(II) centers, in mondentate and tridentate manners, respectively. The copper(II) centers show a variety of coordination numbers and geometries: square-planar (1, 7), octahedral (4) and square-based pyramidal (2, 3, 5, 6). Thermal studies (TGA/DSC) and magnetic susceptibility measurements have been undertaken on all compounds

Pentaborate(1-) Salts and a Tetraborate(2-) Salt Derived from C 2- or C 3-Linked Bis(alkylammonium) Dications:Synthesis, Characterization, and Structural (XRD) Studies.

The synthesis of a number of pentaborate(1-) salts from cations arising from N-substituted α,α-, α,β-, and α,-diaminoalkanes has been attempted in aqueous solution from B(OH)3 and the appropriate diammine in a 10:1 ratio. Despite relatively mild work-up conditions the pentaborate(1-) salts prepared were not always as anticipated and the following compounds were isolated in good yield: [Me2NH(CH2)2NHMe2][B5O6(OH)4]2 (1), [Et2NH(CH2)2NHEt2][B5O6(OH)4]2 (2), [Et2NH2][B5O6(OH)4] (3), [Me2NH2][B5O6(OH)4] (4), [Me2NH(CH2)3NHMe2][B5O6(OH)4]2 (5), [Et2NH(CH2)3NHEt2][B5O6(OH)4]2 (6), [Me3NCH2CH=CH2][B5O6(OH)4] (7), and [Me3N(CH2)3NMe3] [B5O6(OH)4]2.0.5H2O (8). The tetraborate(2-) salt, [Me3N(CH2)2NMe3][B4O5(OH)4].2B(OH)3 .2H2O (9) was obtained in moderate yield (41%) from a 3:1 reaction of B(OH)3 with [Me3N(CH2)2NMe3](OH)2. All compounds were characterized by spectroscopy (1H, 11B, 13C NMR and IR) and thermal gravimetric analysis (TGA). BET analysis on materials derived thermally from selected samples (1, 2, 6, 7) all had porosities of &lt; 1 m2/g, demonstrating that they were non-porous. Single-crystal XRD structures were obtained for 2, 3, 7, 8 and 9 and all contain extensive H-bonded polyborate lattices.</p

Oxidopolyborate anions templated by transition-metal complex cations: Self-assembled syntheses and structural studies (XRD) of [Co(NH3)(6)](2)[B4O5(OH)(4)](3)center dot 11H(2)O, [Ni(phen)(3)][B7O9(OH)(5)]center dot 9.5H(2)O and [Zn(dac)(2)(H2O)(2)][B7O9(OH)(5)]center dot H2O

The new oxidopolyborate salts [Co(NH3) 6] 2[B4O5(OH)4] 3·11H2O (1), [Ni(phen)3][B7O9(OH)5]·9.5H2O (2), and [Zn(dac)2(H2O)2][B7O9(OH)5]·H2O (3), were crystallized, in moderate yields, from aqueous solutions containing B(OH)3 and the hydroxide salt of the corresponding cationic metal complex (prepared in situ) in moderate yields. Complexes 1–3, characterized by spectroscopic (NMR, IR) and thermal (TGA) methods and by single-crystal XRD studies, were obtained through cation-templated self-assembly reactions. Compound 1 contains insular tetraborate2- anions (4-1:2Δ + 2T) and 2 and 3 both contain insular heptaborate2- anions (‘O+’ isomer, 6:(3Δ + 3T) + Δ). The X-ray structures show that in all three compounds the polyborate anions are H-bonded together into extended networks, and there are multiple cation-anion H-bond interactions present in 1 and 3. Compound 2 has cation-cation π-stacking interactions. These interactions are likely to be responsible for templating the observed structures. Thermal decomposition of 1–3 in air yielded amorphous anhydrous borates of composition CoB6O10.5, NiB7O11.5 and ZnB7O11.5, respectively. </p

Synthesis and characterization of a tertiary amine:boric acid (1:1) co-crystal and a neutral zwitterionic diamine pentaboron adduct

The syntheses of the 4,4′-trimethylenebis(N-methylpiperidine):boric acid (1:1) co-crystal, 4,4′-(1-MeNC5H9)2(CH2)3.B(OH)3 (1), and a zwitterionic tetrahydroxidohexaoxidopentaboron adduct, [B5O6(OH)4(κN-NH2CH2CH2NHEt2).H2O (2), (NH2CH2CH2NEt2 = deen) from appropriate combinatorial libraries primed with B(OH)3, are reported together with their spectroscopic (NMR, IR) and single-crystal XRD characterization data. Solid-state H-bond interactions are the likely strong drivers for their formation, and these are described in detail. H-bond networks present in co-crystal 1 include C22(16), R22(8), and R66(36) whilst zwitterionic pentaboron derivative 2 has three R22(8) intermolecular H-bond interactions and the Et2NH- group is involved in a S(7) intramolecular H-bond. Thermal (TGA/DSC) data are also reported for 1 which thermally decomposes to B2O3, in a multistage process: dehydration (60–70 °C) and oxidation and further dehydration (90–700 °C).</p

Oxidoborates templated by cationic nickel(II) complexes and self-assembled from B(OH)3

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 trans-[Ni(NH3)4(H2O)2][B4O5(OH)4].H2O (1), s-[Ni(dien)2][B5O6(OH)4]2 (dien = N-(2-aminoethyl)-1,2-ethanediamine (2), trans-[Ni(dmen)2(H2O)2] [B5O6(OH)4]2.2H2O (dmen = N,N-dimethyl-1,2-diaminoethane) (3), [Ni(HEen)2][B5O6(OH)4]2 (HEen = N-(2-hydroxyethyl)-1,2-diaminoethane) (4), [Ni(AEN)][B5O6(OH)4].H2O (AEN = 1-(3-azapropyl) -2,4-dimethyl-1,5,8-triazaocta-2,4-dienato(1-)) (5), trans-[Ni(dach)2(H2O)2][Ni(dach)2] [B7O9(OH)5]2.4H2O (dach = 1,2-diaminocyclohexane) (6), and the neutral species trans-[Ni(en)(H2O)2{B6O7(OH)6}].H2O (7) (en = 1,2-diaminoethane), and [Ni(dmen)(H2O){B6O7(OH)6}].5H2O (8). Compounds 1–8 were characterized by single-crystal XRD studies and by IR spectroscopy and 2, 4–7 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: 1 has an insular tetraborate(2-) anion, 2–5 have insular pentaborate(1-) anions, 6 has an insular heptaborate(2-) anion (‘O+’ isomer), whilst 7 and 8 have hexaborate(2-) anions directly coordinated to their Ni(II) centers, as bidentate or tridentate ligands, respectively. The Ni(II) centers are either octahedral (1–4, 7, 8) or square-planar (5), and compound 6 has both octahedral and square-planar metal geometries present within the structure as a double salt. Magnetic susceptibility measurements were undertaken on all compounds.</p