Structural Regulation and Oxygen Reduction Reaction Activity of [Co(bpy)2BO2(OH)] and [Cu(bpy)(OH)]2- Complex Templated Borates

Two templated borates, [Co(bpy)₂BO₂(OH)]·[B₅O₆(OH)₄]·H₃BO₃·H₃O·H₂O (1) and [Cu(bpy)(OH)]₂·[B₅O₆(OH)₄]₂·H₂O (2), have been synthesized successfully and characterized by single-crystal X-ray diffraction, powder X-ray diffraction, and Fourier transform infrared. The [Co(bpy)₂BO₂(OH)] complex in 1 shows a very rare coordination mode between Co²⁺ and BO₂(OH)^2-. The structures of 1 and 2 can be adjusted by changing the reagent. The oxygen reduction reaction activity of these Co- and Cu-based catalysts was studied. The E_1/2 values of Co-C-750 and Cu-C-750 are 0.864 and 0.837 V, respectively.

Two New 1D Supramolecular Compounds Based on PbI2 for Efficient Iodine Capture

Two new inorganic-organic hybrid crystals based on PbI2 were assembled through the solvent evaporation method, namely, {[L1]·[Pb2I6]}n (1) and {[L2]2·[Pb3I10]}n (2). L1-L2 are a series of multivalent nitrogen-containing cationic ligands. Compounds 1–2 were characterized by single-crystal X-ray diffraction, elemental analysis, FT-IR, powder X-ray diffraction, and thermogravimetric microanalysis. The results showed that the adsorption rate of 80 mg compound 1 to iodine reached 96.59%, indicating a high iodine capture performance in cyclohexane solution. In the meantime, the adsorption kinetics is most suitable for a pseudo-second-order model, and the adsorption process is mainly chemisorption. Adsorption thermodynamics is most suitable for the Langmuir model, indicating that adsorption occurs on the surface of the monolayer. According to the adsorption mechanism, it can be inferred that the structure of compound 1 contains amino, benzene, N heterocyclic, and other active groups, that is, indirectly increases the adsorption site with iodine, and the chemical reaction with iodine improves the removal rate of iodine in cyclohexane solution. In addition, compound 1 was found to have good iodine adsorption and recyclability by cyclic experiments. Therefore, the synthesized compound 1 can be used as a potential and excellent iodide capture adsorbent, which may have a good application prospects in the future.

One Luminescent Cadmium Iodide with Free Bifunctional Azole Sites as a Triple Sensor for Cu2+, Fe3+, and Cr2O72- Ions

The exploration of an excellent triple sensor for monitoring Cu²⁺, Fe³⁺, and Cr₂O₇^2- ions is of exceeding significance because of their serious effects on the human body. Herein, optically active 1H-3,5-bis(pyrazinyl)-1,2,4-triazole (Hbpt) with triazolyl and pyrazinyl groups was applied for the construction of a new type of organic hybrid cadmium iodide [Cd₆I₈(bpt)₄(H₂O)₄]·2H₂O (1) incorporating a hitherto-unknown [Cd₃I₄(H₂O)₂]²⁺ trimeric-cationic unit, which shows an orange light emission at 589 nm with a large Stokes shift of 246 nm. In virtue of the existence of free bifunctional azole sites as the receptors, 1 exhibits a highly selective and sensitive sensing property toward Cu²⁺, Fe³⁺, and Cr₂O₇^2- ions in aqueous solution with lower detection limits of 0.70∼4.46 ppm, which offers the sole example of cadmium iodide as an excellent triple sensor for detecting Cu²⁺, Fe³⁺, and Cr₂O₇^2- ions. Moreover, temperature-dependent luminescent determinations also reveal that 1 can be used as the potential luminescent molecular thermometer.

Structural Characterization and ORR Activity of a Copper Complex Borate and an Unexpected [Ni(atta)(SO4)0.5]+ Borate-Sulfate

Two metal templated borates, [Ni(atta)(SO₄)_0.5]·[B₅O₆(OH)₄] (1) and [Cu(1-MI)₄]·[B₅O₆(OH)₄]₂·1-MI₂ (2), have been synthesized. The structures were determined by single-crystal X-ray diffraction and further characterized by Fourier transform infrared (FTIR), elemental analysis, and powder X-ray diffraction (PXRD). The structure of 1 consists of [B₅O₆(OH)₄]^- clusters and [Ni(atta)(SO₄)_0.5]⁺ complexes, which shows a very rare Ni-O-S bond. 1 and 2 exhibit a hydrogen-bonded network formed by [B₅O₆(OH)₄]^- clusters. Oxygen reduction reaction (ORR) activities of 1 and 2 were explored.

BO3 Triangle and B@Zn2O3 Cationic Layer in the Structure of the Hybrid Zinc Acetate Borate [ZnAc]·[ZnBO3]

A zinc acetate borate, [ZnAc]·[ZnBO₃] (1), was synthesized under mild conditions; the B@Zn₂O₃ layer of 1 contains a 6-membered ring embedded with a rare BO₃ unit. The layers are pillared by acetate ions to form a 3D framework. The pillared structure of 1 supplies enough space as a nanoreactor, and the related application of CO₂-to-CO reduction has been confirmed.

Three Inorganic-Organic Hybrid Gallo-/Alumino-Borates with Porous-Layered Structures Containing [MB4O10(OH)] (M = Al/Ga) Cluster Units

Three inorganic-organic hybrid gallo-/alumino-borates [Ga₂B₇O₁₄(OH)]·H₂dah (1, dah = 1,6-diaminohexane), K₂[Ga₂B₇O₁₄(OH)(en)_0.5] (2, en = ethylenediamine), and K₂[Al₂B₇O₁₄(OH)(en)_0.5]·H₂O (3) were synthesized under solvothermal conditions. Compound 1 features a 3D porous-layered structure built by the alternation of [GaB₄O₁₀(OH)]^6-, [B₃O₆]^3- clusters and GaO₄ tetrahedra, in which the novel [GaB₄O₁₀(OH)]^6- cluster is first observed. Compounds 2 and 3 are isostructural and made by [MB₄O₁₀(OH)]^6-, [B₃O₆(en)_0.5]^3- clusters and MO₄ tetrahedra (M = Ga/Al); their 3D porous layers are similar to those of 1 and further bridged by en linkers through the rare B-N-C covalent bonds, resulting in the 3D inorganic-organic hybrid framework. This is the first main-group metal borate with organic molecules participating in the oxoboron frameworks through B-N bonds. Optical diffuse-reflectance spectra reveal that 1, 2, and 3 are potential wide-band-gap semiconductors.