Main Group Chemistry

Five high-nitrogen ion salts were first synthesized with the nitrogen-rich ligand 4,5-bis(1H-tetrazol-5-yl)-1H-imidazole (H₃BTI) and Guanidine Carbonate (G₂CO₃), Ethylenediamine (EDA), 1,2-Propanediamine (PN), Hydroxylamine Hydrochloride (HN), and were characterized by elemental analysis and Fourier transform infrared (FT-IR) spectroscopy. Their crystal structures were determined by applying X-ray single crystal diffraction. The results showed a large amount of π-π stacking action in their ligand anions. The thermal decomposition curves of five compounds were obtained by differential scanning calorimetry (DSC). The non-isothermal kinetic parameters of the exothermic process were calculated by Kissinger’s and Ozawa’s methods. Five compounds have relatively high exothermic peak temperatures and thermal explosion temperatures (T_b), which indicates excellent thermal stability and safety.

 The controllable synthesis of MOF materials is of great significance for its application. At present, the regulation of MOF morphology is mainly limited to those composed of transition metal elements, such as IRMOF, ZIF-8, HKUST-1, UiO-66, and MIL-MOFs etc, and few reports about the fabrication of micro/nano sized lanthanide MOFs could be found in literature. In this paper, micron sized Eu-1,4-NDC-fcu-MOF octahedral particles were obtained via a modified solvothermal method by using methylamine as a modulator. The luminous efficiency of Eu³⁺ was greatly improved due to the efficient energy transfer from the 1,4-NDC ligand to rare earth ion. The resultant Eu-1,4-NDC-fcu-MOFs particles could be used to detect benzidine in ethanol solution effectively, and as the concentration of benzidine increased, the fluorescence intensity of Eu-1,4-NDC-fcu-MOFs gradually decreased. Due to the good stability, high luminescent intensity and excellent sensitivity, this work further demonstrates that Ln-MOF are ideal fluorescent probes to identify specific molecules.

A 3D imidazole-bearing cyclophane cage L1 was synthesized as trivalent cationic templates to react with metal halide to obtain a novel organic-inorganic crystalline hybrid: {[CdI₄]₃·(L1)₂} (1). Its crystals have been grown by slow evaporation method and characterized by single-crystal X-ray diffraction analyses, infrared spectra (IR) and powder X-ray diffraction (PXRD). More importantly, the fluorescence property in solid state was studied and found the quenching efficiency is good and it can be used as a recyclable luminescence sensor for Fe³⁺ ions with high selectivity and stability.

One novel metal halide clustered supramolecular polymer, {(BLP) [Ag₈Br₁₂]_0.5}_n(BLP = 1, 3-bis(3,5-lutidine)propane) has been synthesized via the self-assembly reaction in solution. 1 was characterized by X-ray crystal structure, PXRD, TG, elemental analysis, and UV-Vis. This compound exhibits two-dimensional polyrotaxane structure. Great efforts were devoted to investigate its applications in wastewater purification on the basis of methylene blue (MB) degradation.

In this paper, one 3D imidazole cyclophane trivalent cation was chosen with the aim of studying conformational behavior. One novel organic-inorganic hybrid supramolecule {L1·(NH₄) [Mo₈O₂₆]·(H₂O)} (1), has been synthesized through the self-assembly reaction. Compound 1 has been expressly confirmed by PXRD, IR, X-ray single crystal diffraction, and TG. Crystallographic analysis shows that the anion of compound 1 is Multi-core structure. TG shows that the stability of compound 1 is relatively good.

Three compounds consisting of bis(benzimidazole) ligand, namely {[L₁ZnBr₂](CH₃OH)₂} (1), {[L₁Co(CH₃COO)CH₃O]·CH₃OH} (2), {[L₁(NO₃)₂]} (3) have been prepared. (L₁ = 1,2-bis((1H-benzo[d]imidazol-2-yl)methyl)benzene). Among them, (1)-(2) are complexes and ligand L₁ coordinate with metal ions to form extraordinary polyhedron helicate units. (3) is supramolecular. This new study not only enriches the complexs of benzimidazole, but also expands to the research on adsorption, photocatalysis and fluorescence properties.

Two novel extended metallohelical complex structures based on the bis(benzimidazole) ligand L₁, (L₁ = 1,2-bis((1H-benzo[d]imidazol-2-yl)methyl)benzene), namely {[L₁Cd₂(SCN)₂(CH₂)₄(COO)₂(CH₃OH)₂]·2CH₃OH} (1), {[L₁Cd(CH₂)₄(COO)₂]·CH₃CH₂OH}_n (2) have been synthesized and characterized by IR spectroscopy, X-ray Powder Diffraction (PXRD), UV-vis diffuse reflectance spectra, single-crystal X-ray diffraction and fluorescence in the solid state. Binuclear structure for 1, Crystal data: triclinic P-1, a = 9.5222(3), b = 10.9280(4), c = 14.2859(6), α= 108.528(4)°, β= 95.878(3)°, γ= 96.875(3)°, V = 1383.72(9) ų, Z = 2, D_calc = 1.548 g cm^-3; 1D chain structure for 2, Crystal data: triclinic Pbc21, a = 11.6609(7), b = 14.9534(11), c = 16.2444(9), α= 90°, β= 90°, γ= 90 °, V = 2832.5(3) ų, Z = 4, D_calc = 1.503 g cm^-3. In addition, the optical band gap, photocatalytic and adsorption of compounds 1-2 were also investigated.