Mononuclear Transition Metal Complexes of 7-Nitro-1,3,5-Triazaadamantane

This is the peer reviewed version of the following article: Wagner, G., Horton, P. N., & Coles, S. J. (2016). Mononuclear Transition Metal Complexes of 7-Nitro-1,3,5-Triazaadamantane. ChemistrySelect, 1(8), 1548-1555. DOI: 10.1002/slct.201600502, which has been published in final form at http://onlinelibrary.wiley.com/doi/10.1002/slct.201600502/abstract. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-ArchivingComplexes of the type [MCl2(7-nitro-1,3,5-triaza-adamantane)2] (M = Zn(II), Pd(II), Pt(II)) and [MCl2(H2O)2(7-nitro-1,3,5-triazaadamantane) 2] (M = Mn (II), Co(II), Ni(II)) have been prepared and their structures have been analysed by X-ray crystallography, elemental analysis, IR and solid state 13C and 15N NMR spectroscopy, supported by density functional theory/ gauge independent atomic orbital (DFT/GIAO) calculations. In each case, 7-nitro-1,3,5-triazaadamantane acts as a mono-dentate ligand and binds to one metal centre only, in spite of the presence of three equivalent amino nitrogens. In the Co(II) and Ni(II) complexes, a two-dimensional intermolecular hydrogen bonding network between the aqua- and the chloro ligands is established. The uncoordinated amines of the 7-nitro-1,3,5-triaza- adamantane are not involved in any H-bonding, as a result of the exceptionally low basicity of this compound

Copper(2+) Complexes of Hydroxyoxidoborates. Synthesis and Characterization of Two Clusters Containing the Hexaborate(2-) Ligand: [Cu(NH2CH2CH2NEt2){B6O7(OH)(6)}]center dot 5H(2)O and [Cu(NH3)(2){B6O7(OH)(6)}]center dot 2H(2)O

[Cu(NH 2 CH 2 CH 2 NEt 2 ){B 6 O 7 (OH) 6 }]·5H 2 O (1) and [Cu(NH 3 ) 2 {B 6 O 7 (OH) 6 }]·2H 2 O (2) have been obtained as crystalline materials from aqueous solutions of Dynamic Combinatorial Libraries (DCLs) originating from B(OH) 3 and appropriate Cu(II) amine complexes. These two Cu/O/B clusters are formed through self-assembly processes and contain tridentate hexaborate(2−)-κ 3 O ligands. Both compounds have been characterized by TGA/DSC, magnetic susceptibility measurements, IR spectroscopy, and single-crystal XRD studies. The intermolecular H-bond interactions between neighbouring hexaborate units are implicated in their templated synthesis. Compound 2 is a coordination polymer and stabilization is also gained through formation of an additional O–Cu coordinate bond. Steric congestion in 1 blocks formation of this bond resulting in insular complexes. </p

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

Programmable synthesis of organic cages with reduced symmetry

Integrating symmetry-reducing methods into self-assembly methodology is desirable to efficiently realise the full potential of molecular cages as hosts and catalysts. Although techniques have been explored for metal organic (coordination) cages, rational strategies to develop low symmetry organic cages remain limited. In this article, we describe rules to program the shape and symmetry of organic cage cavities by designing edge pieces that bias the orientation of the amide linkages. We apply the rules to synthesise cages with well-defined cavities, supported by evidence from crystallography, spectroscopy and modelling. Access to low-symmetry, self-assembled organic cages such as those presented, will widen the current bottleneck preventing study of organic enzyme mimics, and provide synthetic tools for novel functional material design

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

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

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&#8722;) complexes, [Zn{&#954;3O-B6O7(OH)6}(&#954;3N-dien)]&#183;0.5H2O (dien = NH(CH2CH2NH2)2) (1) and (NH4)2[Zn{&#954;2O-B6O7(OH)6}2(H2O)2]&#183;2H2O (2), and a zinc(II) dodecaborate(6&#8722;) complex, (1,3-pnH2)3[(&#954;1N-H3N{CH2}3NH2)Zn{&#954;3O-B12O18(OH)6}]2&#183;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&#8722;) anions in 1 and 2 are coordinated to octahedral Zn(II) centres as tridentate (1) or bidentate ligands (2) and the dodecaborate(6&#8722;) ligand in 3 is tridentate to a tetrahedral Zn(II) centre