Elevating the energetic capabilities of metal coordination compounds by incorporating nitrate anions.

In the realm of energetic materials research, there has been notable interest in energetic coordination compounds (ECCs) owing to their remarkable thermal stability and resistance to mechanical stimuli. This study successfully demonstrated the synthesis of an azole-based C-C bonded ECC1 under ambient conditions. A comprehensive characterization study, employing techniques such as IR, TGA-DSC, NMR and single-crystal X-ray diffraction analysis, was conducted. The bulk compound was investigated by PXRD analysis. In-depth exploration of its physicochemical and energetic performance revealed good detonation properties such as a detonation velocity (VOD) of 8553 m s-1 and a detonation pressure (DP) of 36.2 GPa, which surpass those of heat resistant explosives HNS and TATB. Due to its remarkable high melting and onset decomposition temperature (278/379 °C), it also outperforms the benchmark explosive HMX (279 °C) and the heat-resistant explosive HNS (318 °C) and shows a high impact sensitivity (IS) of 20 J and friction sensitivity (FS) of 360 N. The study also employed Hirshfeld surface and 2D fingerprint analysis to elucidate the close contact of atoms within the molecules. The combination of high detonation properties, thermal stability, and low sensitivity makes the synthesized ECC1 intriguing for further investigations and suggests its potential applications as a safe and high-energy-dense material.

Solvent Free Potassium 3,5-dinitro-6-oxo-1,6-dihydropyrazin-2-olate 3D EMOF as Thermally Stable Energetic Material.

Heat-resistant explosives play a vital role in indispensable applications. For this, we have synthesized a novel, three-dimensional, solvent-free energetic metal-organic framework (EMOF) potassium 3,5-dinitro-6-oxo-1,6-dihydropyrazin-2-olate (KDNODP) straightforwardly. The synthesized EMOF was characterized through IR, NMR spectroscopy, elemental analysis, and differential scanning calorimetry studies. Furthermore, single-crystal X-ray diffraction provided a complete description of KDNODP. It exhibits a three-dimensional EMOF structure with remarkably balanced properties such as high density (2.11 g cm-3), excellent thermal stability (291 °C), good detonation performance (8127 m s-1 and 26.94 GPa) and low mechanical sensitivity (IS=35 J; FS=360 N) than the commonly used heat-resistant explosives HNS (density=1.74 g cm-3; VOD=7164 m s-1, DP=21.65 GPa, IS=5 J) as well as the similar reported energetic potassium MOFs. To gain insights into the packing and intermolecular interactions, the Hirshfeld surface and a 2D fingerprint analysis were examined. Additionally, scanning electron microscopy was used to investigate the particle size and morphological characteristics of KDNODP. These outcomes highlight a successful method for creating 3D EMOF based on a six-membered heterocycle as a potential heat-resistant energetic material.

Isolated Inflammatory Necrosis of the Falciform Ligament: A Case Report with Review of Literature.

Inflammatory necrosis of the falciform ligament is an extremely rare cause of acute right upper quadrant pain. Due to overlapping symptoms with pathologies affecting the gall bladder and liver, this poses a diagnostic challenge with limited existing literature. Here, we report a case of a 62-year-old female patient presenting in the accident and emergency department with right upper quadrant pain. The patient underwent ultrasonography and revealed thickened and echogenic falciform ligament. Further, a computed tomography revealed swollen falciform ligament with associated fat stranding. The patient was kept under conservative management and improved over 2 weeks.

Efficient preparation of hybrid biofuels from biomass-derived 5-(acetoxymethyl)furfural and petroleum-derived aromatic hydrocarbons.

Fuel candidates containing both petroleum-derived and biomass-derived molecules in their structural motifs ensure both feedstocks are used optimally and coherently. This work reports a straightforward and efficient preparation of 5-(arylmethyl)furfurals (AMFFs), 2-(arylmethyl)furans (AMFs), and 2-(arylmethyl)-5-methylfurans (AMMFs) as hybrid biofuels (or fuel oxygenates) starting from carbohydrate-derived 5-(acetoxymethyl)furfural (AcMF) and petroleum-derived aromatic hydrocarbons. The AMFFs were prepared by Friedel-Crafts reaction between AcMF and aromatic hydrocarbons (e.g., BTX, mesitylene) by employing anhydrous ZnCl2 as the catalyst. AMFs were prepared by decarbonylation of AMFFs over the Pd(OAc)2 catalyst under solvent-free conditions. In contrast, AMMFs were produced by hydrogenating AMFFs in methanol using gaseous hydrogen and the 10% Pd/C catalyst. The catalytic transformations were optimized on various parameters, and all the biofuel candidates were obtained in good to excellent isolated yields (>80%) under moderate conditions.

Synthesis of Advanced Pyrazole and N-N-Bridged Bistriazole-Based Secondary High-Energy Materials.

In this work, we have synthesized 3,5-dihydrazinyl-4-nitro-1H-pyrazole (2), 9-nitro-1H-pyrazolo[3,2-c:5,1-c']bis([1,2,4]triazole)-3,6-diamine (3), and N-N-bonded N,N'-{[4,4'-bi(1,2,4-triazole)]-3,3'-diyl}dinitramide (5) and its stable nitrogen-rich energetic salts in one and two steps in quantitative yields from commercially available inexpensive starting material 4,6-dichloro-5-nitropyrimidine (1). Along with characterization via nuclear magnetic resonance, infrared, differential scanning calorimetry, and elemental analysis, the structures of 2 and 4-8 were confirmed by single-crystal X-ray diffraction. Interestingly, 5-8 show excellent thermal stability (242, 221, 250, and 242 °C, respectively) compared to that of RDX (210 °C). Detonation velocities of 2, 4, 6, and 7 range from 8992 to 9069 m s-1, which are better than that of RDX (8878 m s-1) and close to that of HMX (9221 m s-1). All of these compounds are insensitive to impact (10-35 J) and friction (360 N) sensitivity. These excellent energetic performances, stabilities, and synthetic feasibilities make compounds 2, 4, 6, and 7 promising candidates as secondary explosives and potential replacements for the presently used benchmark explosives RDX and HMX.

Energetic coordination compounds: self-assembled from the nitrogen-rich energetic C-C bonded pyrazoles and triazoles.

In energetic materials research, energetic coordination compounds (ECCs) have received much attention due to their high thermal stability and insensitivity to mechanical stimuli. The energetic characteristics of ECCs can be modified by combining various metal cations, potent anions, and ligands. In this study, we have synthesized two energetic ligands, 5-(4-nitro-1H-pyrazol-3-yl)-1H-1,2,4-triazol-3-amine (NPTA) and (Z)-N-(5-(4-nitro-1H-pyrazol-3-yl)-2,4-dihydro-3H-1,2,4-triazol-3-ylidene)nitramide (NPTN), from a commercially viable starting material and reacted them with nitrate salts of various 3d metals (e.g., Ni, Co, Zn) to obtain six new ECCs, [Ni(NPTA)(H2O)3]2·2NO3 (1), [Co(NPTA)(H2O)3]2·2NO3 (2), [Zn(NPTA)(H2O)3]2·2NO3 (3), [Ni(NPTN)(H2O)3]2 (4), [Co(NPTN)(H2O)3]2 (5), and [Zn(NPTN)(H2O)3]2 (6) under ambient conditions. All the newly prepared ECCs were characterised through PXRD, IR, SEM, and TGA-DSC analysis. Furthermore, single crystal analysis proved that 1-6 are dimeric complexes. Moreover, 1-6 show excellent density ranges from 1.94 to 2.06 g cm-3 and remarkable thermal stability (216-352 °C), and are highly insensitive towards impact (>40 J) and friction (>360 N), describing their potential as high performing energetic materials. All the ECCs revealed good enthalpy of combustion (-6.3 to -9.94 kJ g-1). Additionally, the Hirshfeld surface and 2D fingerprint analysis were used to understand the close contact of atoms within the molecules. High crystal densities, thermal stabilities and low sensitivities make the synthesized ECCs interesting for further studies and potential applications as safe high-energy dense materials.

Straightforward Synthesis of Insensitive 2-(1-Hydroxy-2,2-dinitrovinyl)guanidine and Its Guanidinium Dinitromethanide Salt as a High Energy Density Material.

High energetic 2-(1-hydroxy-2,2-dinitrovinyl)guanidine and guanidinium dinitromethanide (GDNM) salt were synthesized in one and two steps using a simple and cost-effective methodology from commercially available inexpensive starting materials with a high yield. NMR, IR spectroscopy, elemental analysis, and differential scanning calorimetry studies were used to characterize compound 2a and GDNM salt. Single-crystal XRD, Hirshfeld surface analysis, and SEM analysis were used to study the crystal structure, hydrogen-bonding/noncovalent interactions, and morphology of the GDNM salt, respectively. The physicochemical and energetic properties of compound 2a and GDNM salt reveal their good energetic performance, specific impulse, and high mechanical insensitivity, which are better than that of propellants such as ADN and AP and close to that of the benchmark explosives such as RDX and FOX-7.

Preparation of 5-(Acyloxymethyl)furfurals from Carbohydrates Using Zinc Chloride/Acetic Acid Catalyst System and Their Synthetic Value Addition.

5-(Acyloxymethyl)furfurals (AMFs) have received considerable attention as hydrophobic, stable, and halogen-free congeners of 5-(hydroxymethyl)furfural (HMF) for synthesizing biofuels and biochemicals. In this work, AMFs have been prepared directly from carbohydrates in satisfactory yields using the combination of ZnCl2 as the Lewis acid catalyst and carboxylic acid as the Brønsted acid catalyst. The process was initially optimized for 5-(acetoxymethyl)furfural (AcMF) and then extended to producing other AMFs. The effects of reaction temperature, duration, loading of the substrate, and dosage of ZnCl2 on AcMF yield were explored. Fructose and glucose provided AcMF in 80% and 60% isolated yield, respectively, under optimized parameters (5 wt % substrate, AcOH, 4 equiv ZnCl2, 100 °C, 6 h). Finally, AcMF was converted into high-value chemicals, such as 5-(hydroxymethyl)furfural, 2,5-bis(hydroxymethyl)furan, 2,5-diformylfuran, levulinic acid, and 2,5-furandicarboxylic acid in satisfactory yields to demonstrate the synthetic versatility of AMFs as carbohydrate-derived renewable chemical platforms.

High-performing, insensitive and thermally stable energetic materials from zwitterionic gem-dinitromethyl substituted C-C bonded 1,2,4-triazole and 1,3,4-oxadiazole.

A series of gem-dinitromethyl substituted zwitterionic C-C bonded azole based energetic materials (3-8) were designed, synthesized, and characterized through NMR, IR, EA, and DSC studies. Further, the structure of 5 was confirmed with SCXRD and those of 6 and 8 with 15N NMR. All the newly synthesized energetic molecules exhibited higher density, good thermal stability, excellent detonation performance, and low mechanical sensitivity to external stimuli such as impact and friction. Among all, compounds 6 and 7 may serve as ideal secondary high energy density materials due to their remarkable thermal decomposition (200 °C and 186 °C), insensitivity to impact (>30 J), velocity of detonation (9248 m s-1 and 8861 m s-1) and pressure (32.7 GPa and 32.1 GPa). Additionally, the melting and decomposition temperatures of 3 (Tm = 92 °C, Td = 242 °C) indicate that it can be used as a melt-cast explosive. The novelty, synthetic feasibility, and energetic performance of all the molecules suggest that they can be used as potential secondary explosives in defence and civilian fields.

Promising Thermally Stable Energetic Materials with the Combination of Pyrazole-1,3,4-Oxadiazole and Pyrazole-1,2,4-Triazole Backbones: Facile Synthesis and Energetic Performance.

Thermally stable energetic materials have broad applications in the deep mining, oil and natural exploration, and aerospace industries. The quest for thermally stable (heat-resistant) energetic materials with high energy output and low sensitivity has fascinated many researchers worldwide. In this study, two different series of thermally stable energetic materials and salts based on pyrazole-oxadiazole and pyrazole-triazole (3-23) with different explosophoric groups have been synthesized in a simple and straightforward manner. All the newly synthesized compounds were fully characterized by IR, ESI-MS, multinuclear NMR spectroscopy, elemental analysis, and thermogravimetric analysis-differential scanning calorimetry measurements. The structures of 3, 7, and 22 were supported by single-crystal X-ray diffraction studies. The density, heat of formation, and energetic properties (detonation velocity and detonation pressure) of all the compounds range between 1.75 and 1.94 g cm-3, 0.73 to 2.44 kJ g-1, 7689 to 9139 m s-1, and 23.3 to 31.5 GPa, respectively. All the compounds are insensitive to impact (>30 J) and friction (>360 N). In addition, compounds 4, 6, 10, 14, 17, 21, 22, and 23 show high onset decomposition temperature (Td between 238 and 397 °C) than the benchmark energetic materials RDX (Td = 210 °C), HMX (279 °C), and thermally stable HNS (318 °C). It is noteworthy that the pyrazole-oxadiazole and pyrazole-triazole backbones greatly influence their physicochemical and energetic properties. Overall, this study offers a perspective on insensitive and thermally stable nitrogen-rich materials and explores the relationship between the structure and performance.

Epidemiology of Congenital Heart Disease in India.

OBJECTIVE: Congenital heart defects (CHDs) affect a large number of newborns and account for a high proportion of infant mortality worldwide. There are regional differences in the prevalence and distribution pattern of CHDs. The aim of this study is to estimate the distribution pattern and prevalence of CHDs among the population of north-central India and to compare the results with studies in other regions of the country to get an overview of prevalence of CHDs in India. DESIGN: We carried out a prospective study in the outpatient department of a tertiary care referral center in north-central India. This study was carried out from January 2011 to April 2014, with 34 517 individuals being recruited for the study. All patients were examined by chest x-ray, electrocardiogram, and 2D echocardiography. Prevalence rate per 1000 individuals examined was calculated. Relative frequencies of individual CHD types as a proportion of total CHDs were also calculated. RESULTS: Out of 34 517 individuals examined, 661 were diagnosed with CHDs, giving a prevalence of 19.14 per 1000 individuals. The most common defect was ventricular septal defect (33%), followed by atrial septal defect (19%) and tetralogy of Fallot (16%). The majority of CHD cases (58%) diagnosed were between 0 and 5 years of age. The prevalence of CHDs in adults was 2.4 per 1000 individuals in this cohort, with atrial septal defect (44.5%) being the most frequent defect. CONCLUSION: The prevalence of CHDs in our cohort was high, possibly because of the power of the diagnostic methods we used and the inclusion of all age groups. Adults with CHDs may significantly contribute to the prevalence of CHDs in the next generation, and this needs to be considered when estimating prevalence rates. Although several small regional studies have been carried out in India, there is an urgent need to establish a nationwide registry/database for congenital heart defects.