Understanding the structure–property relationship in a material is of great importance in materials science. To study the effect of ligand backbones and anionic groups on the properties of energetic cationic metal–organic frameworks (CMOFs) and to disclose their structure–property relationships, we designed and synthesized a series of CMOFs based on either 4,4′-bi-1,2,4-triazole (btrz) or its azo analogous, 4,4′-azo-1,2,4-triazole (atrz) as ligand, and either perchlorate [ClO4 –] or nitroformate [C(NO2)3 –, NF–] anion as extra-framework anion. Surprisingly, the effect of ligand backbones on the CMOFs is inverse that of the backbones on traditional energetic compounds, while the effect of the anionic groups follows the traditional group law. We found that btrz-based CMOFs exhibit higher densities and better chemical and thermal stabilities than those of their corresponding atrz-based CMOFs, although btrz has a lower density and a lower stability than atrz. In particular, the density of btrz-Fe is more than 0.11 g cm–3 higher than that of its atrz-based analogue (atrz-Fe). Moreover, the decomposition temperature of btrz-Zn (363 °C) is 80 °C higher than that of atrz-Zn, even higher than that of 1,3,5-triamino-2,4,6-trinitrobenzene (TATB), making it a potential heat-resistant explosive. The effect mechanisms were also discussed according to the experimental results. This investigation is significant for understanding the structure–property relationship in energetic CMOFs. Moreover, it also brings about new design rules for future high-performance energetic materials.
High-energy metal–organic frameworks (MOFs) based on nitrogen-rich ligands are an emerging class of explosives, and density is one of the positive factors that can influence the performance of energetic materials. Thus, it is important to design and synthesize high-density energetic MOFs. In the present work, hydrothermal reactions of Cu(II) with the rigid polynitro heterocyclic ligands 5,5′-dinitro-2H,2′H-3,3′-bi-1,2,4-triazole (DNBT) and 5,5′-dinitro-3,3′-bis-1,2,4-triazole-1-diol (DNBTO) gave two high-density MOFs: [Cu(DNBT)(ATRZ)3]n (1) and [Cu(DNBTO)(ATRZ)2(H2O)2]n (2), where ATRZ represents 4,4′-azo-1,2,4-triazole. The structures were characterized by infrared spectroscopy, elemental analysis, ultraviolet-visible (UV) absorption spectroscopy and single-crystal X-ray diffraction. Their thermal stabilities were also determined by thermogravimetric/differential scanning calorimetry analysis (TG/DSC). The results revealed that complex 1 has a two-dimensional porous framework that possesses the most stable chair conformations (like cyclohexane), whereas complex 2 has a one-dimensional polymeric structure. Compared with previously reported MOFs based on copper ions, the complexes have higher density (ρ = 1.93 g cm−3 for complex 1 and ρ = 1.96 g cm−3 for complex 2) and high thermal stability (decomposition temperatures of 323 °C for complex 1 and 333.3 °C for complex 2), especially because of the introduction of an N–O bond in complex 2. We anticipate that these two complexes would be potential high-energy density materials.
Tuberculosis (TB) is an important health issue in the world. Although the relation of SLC11A1 polymorphisms with TB risk has been extensively studied, it has not been reported in the northwest Chinese Han population. Therefore, this study aimed to investigate the relationships between five polymorphisms in or near the SLC11A1 gene and susceptibility to TB. The Agena MassARRAY platform was conducted for genotyping from 510 TB patients and 508 healthy controls. Odds ratios (ORs) and 95% confidence intervals (CIs) were analyzed through logistic regression adjustment age and gender to assess the relationships between polymorphisms and TB risk. Our results identified that rs7608307 was related to increased TB risk in males (CT vs. CC: OR = 1.69, 95%CI: 1.12–2.56, p = 0.013; CT-TT vs. CC: OR = 1.61, 95%CI: 1.08–2.41, p = 0.020) and age ≤41 group (CT vs. CC: OR = 1.66, 95%CI: 1.04–2.65, p = 0.035), respectively. The SNP rs13062 was associated with the TB risk both in males (p = 0.012) and age >41 group (p = 0.021). In addition, we observed that the CC genotype of rs4674301 was correlated with increased TB risk in females (p = 0.043). Our results demonstrated the relationships between polymorphisms (rs7608307, rs4674301, and rs13062) in or near the SLC11A1 gene and age- and sex-specific TB risk in the northwest Chinese Han population.
Energetic ionic salts 1 and 2 containing three heterocyclic anions were prepared in a one-pot reaction using 1,3,5-benzenetricarboxaldehyde, aminoguanidine salts, and organic energetic salts (5-nitrotetrazole and 3,5-dinitro-1,2,4-triazole ammonium salt).
We report a greener and more-general organic method for the synthesis of functional organic salts containing organic anions through a Schiff base reaction between readily available aldehydes and simple aminoguanidinium salts. This reaction is operationally simple, free of metal salts, and forms water as the sole byproduct. The broad scope and good functional-group compatibility of this method permit its use to provide ready access to a library of more than 70 distinct organic salts, including those of heterocyclic anions, complex pharmaceutical anions, and polyanions, which are difficult to obtain through classical inorganic methods. Moreover, choosing different aldehydes and organic anions provides a convenient method for modulating or improving the functional properties of the designed organic salts, such as their melting points, fluorescence, and energetic properties. We therefore expect that this method will open new opportunities for the discovery and functionalization of a wide variety of organic salts and functional materials.
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