Nitrogen-Rich Salts Based on the Energetic [Monoaquabis(<i>N</i>,<i>N</i>‑bis(1<i>H</i>‑tetrazol-5-yl)amine)-zinc(II)] Anion: A Promising Design in the Development of New Energetic Materials

Nitrogen-rich energetic salts involving various cations (lithium, <b>1</b>; ammonium, <b>2</b>; hydrazinium, <b>3</b>; hydroxylammonium, <b>4</b>; guanidinium, <b>5</b>; aminoguanidinium, <b>6</b>; diaminoguanidinium, <b>7</b>; and triaminoguanidinium, <b>8</b>) based on nitrogen-rich anion [Zn­(BTA)₂(H₂O)]^2– (N% = 65.37, BTA = <i>N</i>,<i>N</i>-bis­[1<i>H</i>-tetrazol-5-yl]­amine anion) were synthesized with a simple method. The crystal structures of all compounds except <b>1</b>, <b>2</b>, and <b>6</b> were determined by single-crystal X-ray diffraction and fully characterized by elemental analysis and FT-IR spectroscopy. The thermal stabilities were investigated by differential scanning calorimetry (DSC). The DSC results show that all compounds exhibit high thermal stabilities (decomposition temperature >200 °C). Additionally, the heats of formation were calculated on the basis of the experimental constant-volume energies of combustion measured by using bomb calorimetry. Lastly, the sensitivities toward impact and friction were assessed according to Bundesamt für Materialforschung (BAM) standard methods

Nitrogen-Rich Salts Based on the Energetic [Monoaquabis(<i>N</i>,<i>N</i>‑bis(1<i>H</i>‑tetrazol-5-yl)amine)-zinc(II)] Anion: A Promising Design in the Development of New Energetic Materials

Nitrogen-rich energetic salts involving various cations (lithium, <b>1</b>; ammonium, <b>2</b>; hydrazinium, <b>3</b>; hydroxylammonium, <b>4</b>; guanidinium, <b>5</b>; aminoguanidinium, <b>6</b>; diaminoguanidinium, <b>7</b>; and triaminoguanidinium, <b>8</b>) based on nitrogen-rich anion [Zn­(BTA)₂(H₂O)]^2– (N% = 65.37, BTA = <i>N</i>,<i>N</i>-bis­[1<i>H</i>-tetrazol-5-yl]­amine anion) were synthesized with a simple method. The crystal structures of all compounds except <b>1</b>, <b>2</b>, and <b>6</b> were determined by single-crystal X-ray diffraction and fully characterized by elemental analysis and FT-IR spectroscopy. The thermal stabilities were investigated by differential scanning calorimetry (DSC). The DSC results show that all compounds exhibit high thermal stabilities (decomposition temperature >200 °C). Additionally, the heats of formation were calculated on the basis of the experimental constant-volume energies of combustion measured by using bomb calorimetry. Lastly, the sensitivities toward impact and friction were assessed according to Bundesamt für Materialforschung (BAM) standard methods

Ortho Effects of Tricarboxylate Linkers in Regulating Topologies of Rare-Earth Metal–Organic Frameworks

A linker design strategy is developed to attain novel polynuclear rare-earth (RE) metal–organic frameworks (MOFs) with unprecedented topologies. We uncover the critical role of ortho-functionalized tricarboxylate ligands in directing the construction of highly connected RE MOFs. The acidity and conformation of the tricarboxylate linkers were altered by substituting with diverse functional groups at the ortho position of the carboxyl groups. For instance, the acidity difference between carboxylate moieties resulted in forming three hexanuclear RE MOFs with novel (3,3,3,10,10)-c wxl, (3,12)-c gmx, and (3,3,3,12)-c joe topologies, respectively. In addition, when a bulky methyl group was introduced, the incompatibility between the net topology and ligand conformation guided the co-appearance of hexanuclear and tetranuclear clusters, generating a novel 3-periodic MOF with a (3,3,8,10)-c kyw net. Interestingly, a fluoro-functionalized linker prompted the formation of two unusual trinuclear clusters and produced a MOF with a fascinating (3,8,10)-c lfg topology, which could be gradually replaced by a more stable tetranuclear MOF with a new (3,12)-c lee topology with extended reaction time. This work enriches the polynuclear clusters library of RE MOFs and unveils new opportunities to construct MOFs with unprecedented structural complexity and vast application potential

Toward an Operational Machine-Learning-Based Model for Deriving the Real-Time Gapless Diurnal Cycle of Ozone Pollution in China with CLDAS Data

An operational real-time surface ozone (O3) retrieval (RT-SOR) model was developed that can provide a gapless diurnal cycle of O3 retrievals with a spatial resolution of 6.25 km by integrating Chinese Land Data Assimilation System (CLDAS) data and multisource auxiliary information. The model robustly captures the hourly O3 variability, with a sample-based (station-based) cross-validation R2 of 0.88 (0.85) and RMSE of 14.3 μg/m3 (16.1 μg/m3). An additional hindcast-validation experiment demonstrated that the generalization ability of the model is robust (R2 = 0.75; RMSE = 21.9 μg/m3). Compared with previous studies, the model performs comparably or even better at the daily scale and fills the gaps in terms of missing hourly O3 data within the 24-hour cycle. More importantly, underpinned by the RT availability of CLDAS data, the hourly concentration of O3 can be updated in RT, which is expected to advance our understanding of the diurnal cycle of O3 pollution in China