Na5[MB24O34(OH)12]·nH2O (M = Cr3+, Al3+): Unprecedented Spherelike Polyborate Clusters from Boric Acid Flux Synthesis

Na1.5Cs0.5[Al{BO3}{B9O15(OH)3}1/3]: An Acentric Layered Aluminoborate with Nonlinear-Optical Properties

An acentric aluminoborate (ABO), Na1.5Cs0.5[Al{BO3}{B9O15(OH)3}1/3] (1), has been made under solvothermal conditions. The alternations of AlO4 tetrahedra and BO3 triangles first build up the 2D ABO layer with 6-MR (membered-ring) windows. The fanlike B9O15(OH)3 cluster adorns the layer through Al-O-B linkages, producing a pair of unclosed channels with 7-MR aperture on the lateral side of the layers. The novel B9O15(OH)3 cluster represents the largest oxoboron cluster in the acentric ABO family. 1 not only shows a moderate second-harmonic-generation response of 1.2 times that of potassium dihydrogen phosphate but also has a short cutoff edge below 200 nm, indicating its potential applications in deep-UV regions.

Construction of a unique 2-D layered vanadoborate with water-assisted proton conductivity

In the present work, a new two-dimensional layered vanadoborate Na4[V12B18O54(OH)6(H2O)]•(H2en)4•2(OH)•3H2O (1, en = ethylenediamine), based on a [V12B18O54(OH)6(H2O)]10- cluster unit, was hydrothermally obtained and characterized. In the structure, the clusters...

Potassium Ferrite as Heterogeneous Photo-Fenton Catalyst for Highly Efficient Dye Degradation

In this work, hexagon-shaped potassium ferrite (K2Fe4O7) crystals with different sizes were prepared using the hydrothermal method. The crystals showed a narrow band gap of 1.44 eV, revealed by UV-visible diffuse reflectance spectroscopy, and was thus used as a heterogeneous Fenton catalyst to degrade methylene blue (MB) and crystal violet (CV) in the presence of green oxidant H2O2 under visible-light irradiation. Among the investigated crystals, the as-prepared one with an average size of 20 µm (KFO-20) exhibited better photocatalytic activity due to its high surface area. When it was used as a photo-Fenton catalyst, 100% MB and 92% CV were degraded within 35 min. Moreover, the catalyst maintained high photocatalytic activity and was stable after four continuous cycles. The trapping experiments showed that the active hydroxyl radical (·OH) was dominant in the photo-Fenton reaction. Therefore, this new photo-Fenton catalyst has great potential for the photocatalytic degradation of dye contaminants in water.

Ba2ZnSc(BO3)3and Ba4Zn5Sc2(BO3)8: first examples of borates in the Zn–Sc–B–O system featuring special structure configurations

First examples in the Zn–Sc–B–O system featuring a special Zn/Sc–O configuration ([Zn₂(BO₃)₆]¹⁴⁻cluster, lowest-coordinated ScO₅polyhedra, and coexistence of ZnO₄and ZnO₆units).

Series of open-framework aluminoborates containing [B5O10] clusters

Three new open-framework aluminoborates (ABOs), Rb₂AlB₅O₁₀·4H₂O (1), [C₅N₂H₁₆]AlB₅O₁₀ (2, C₅N₂H₁₆ = N-ethyl-1,3-diaminopropane) and [H₂dap][(CH₃)₂NH]AlB₅O₁₀ (3, dap = 1,2-diaminopropane) have been made under solvothermal conditions and characterized. The fluorescence and NLO properties were also studied.

Systematic study of Cr3+ substitution into octahedra-based microporous aluminoborates

Single crystals of pure aluminoborate PKU-1 (Al3B6O11(OH)5·nH2O) were obtained, and the structure was redetermined by X-ray diffraction. There are three independent Al atoms in the R3 structure model, and Al3 locates in a quite distorted octahedral environment, which was evidenced by (27)Al NMR results. This distortion of Al3O6 octahedra release the strong static stress of the main framework and leads to a symmetry lowering from the previously reported R3 to the presently reported R3. We applied a pretreatment to prepare Al(3+)/Cr(3+) aqueous solutions; as a consecquence, a very high Cr(3+)-to-Al(3+) substitution content (∼50 atom %) in PKU-1 can be achieved, which is far more than enough for catalytic purposes. Additionally, the preference for Cr(3+) substitution at the Al1 and Al2 sites was observed in the Rietveld refinements of the powder X-ray data of PKU-1:0.32Cr(3+). We also systematically investigated the thermal behaviors of PKU-1:xCr(3+) (0 ≤ x ≤ 0.50) by thermogravimetric-differential scanning calorimetry, in situ high-temperature XRD in vacuum, and postannealing experiments in furnace. The main framework of Cr(3+)-substituted PKU-1 could be partially retained at 1100 °C in vacuum. When 0.04 ≤ x ≤ 0.20, PKU-1:xCr(3+) transferred to the PKU-5:xCr(3+) (Al4B6O15:xCr(3+)) structure at ∼750 °C by a 5 h annealing in air. Further elevating the temperature led to a decomposition into the mullite phase, Al4B2O9:xCr(3+). For x > 0.20 in PKU-1:xCr(3+), the heat treatment led to a composite of Cr(3+)-substituted PKU-5 and Cr2O3, so the doping upper limit of Cr(3+) in PKU-5 structure is around 20 atom %.

Two Cu-complex directed aluminoborates: from 2D layers to 3D frameworks

Two novel aluminoborates (1 and 2) containing Cu complexes have been prepared under solvothermal conditions. Both are built from AlO₄ groups and [B₅O_10−n(OH)_n] (n = 0 and 2) clusters. 1 features a 2D aluminoborate layer with 16-member rings, whereas 2 is a 3D framework stacked by different building layers, showing the first Cu-complex directed aluminoborate.

Synthesis and structure of QD-6: a novel aluminoborate constructed from unprecedented [B@Al6O24] and polyborate clusters

A novel aluminoborate (NH(4))(6)[C(5)NH(12)](6)[Al(12)B(65)O(105)(OH)(33)]·(H(2)O)(15) (QD-6), has been synthesized under mild hydrothermal conditions and characterized by IR, elemental analysis, TGA, powder and single-crystal X-ray diffractions. This compound crystallizes in the rhombohedral space group R3 (No. 148) with the lattice constants a = 23.7421(2) Å, c = 24.7699(3) Å, V = 12091.9(2) Å(3), and Z = 3. QD-6 consists of two unprecedented aluminoborate clusters, [Al(6)B(34)O(54)(OH)(18)](6-) and [Al(6)B(31)O(51)(OH)(15)](6-), which are built from the same hexagon-like [B@Al(6)O(24)] clusters and [B(11)O(17)(OH)(6)] or [B(10)O(16)(OH)(5)] polyborates.

Cooperative self-assembly of chiral L-malate and achiral succinate in the formation of a three-dimensional homochiral framework

Chiral l-malate and achiral succinate ligands have been integrated into a three-dimensional homochiral framework by reacting transition-metal cations (Mn (2+)), l-(-)-malic acid ( l-H 2ma), succinic acid (H 2suc), and 4,4'-bipyridine (4,4'-bipy). Chiral l-malate bonds to Mn (2+) without using the -OH group, which is very unusual for malate. Such unusual bonding of chiral malate results from the cooperative effect of chiral malate and achiral succinate ligands during the self-assembly process, further assisted by the third complementary bipyridine ligand.