Molecular Design and Property Prediction of High Density Polynitro[3.3.3]-Propellane-Derivatized Frameworks as Potential High Explosives

Research in energetic materials is now heavily focused on the design and synthesis of novel insensitive high explosives (IHEs) for specialized applications. As an effective and time-saving tool for screening potential explosive structures, computer simulation has been widely used for the prediction of detonation properties of energetic molecules with relatively high precision. In this work, a series of new polynitrotetraoxopentaaza[3.3.3]-propellane molecules with tricyclic structures were designed. Their properties as potential high explosives including density, heats of formation, detonation properties, impact sensitivity, etc., have been extensively evaluated using volume-based thermodynamic calculations and density functional theory (DFT).These new energetic molecules exhibit high densities of >1.82 g cm^–3, in which <b>1</b> gives the highest density of 2.04 g cm^–3. Moreover, most new materials show good detonation properties and acceptable impact sensitivities, in which <b>5</b> displays much higher detonation velocity (9482 m s^–1) and pressure (43.9 GPa) than HMX and has a <i>h</i>₅₀ value of 11 cm. These results are expected to facilitate the experimental synthesis of new-generation nitramine-based high explosives

Construction of a Thermally Stable and Highly Energetic Metal–Organic Framework as Lead-Free Primary Explosives

Two energetic compounds, 4,8-dinitraminodifurazano­[3,4-<i>b</i>,<i>e</i>]­pyrazine (<b>1</b>) and its potassium-based energetic metal–organic framework (E-MOF) (<b>2</b>), were prepared, and their crystal structures were confirmed by single-crystal X-ray diffraction analysis. Compound <b>1</b> cocrystallizes with water molecules and shows a three-dimensional (3D) sandwich-like supramolecular structure, which is rare in the known energetic organic compounds. Compound <b>2</b> has a pillared layered structure with a pcu topology. The layered structure in the 3D framework featuring sql topology was constructed from inorganic chains {K₂O} and nitroamine groups. The crystal density of <b>2</b> is up to 2.114 g cm^–3. This potassium-based E-MOF shows high thermal stability, high detonation velocity, and high impact and friction sensitivities, which make it a potential high-performing primary explosive

The complete chloroplast genome sequence of <i>Actinidia arguta</i> using the PacBio RS II platform

<div><p><i>Actinidia arguta</i> is the most basal species in a phylogenetically and economically important genus in the family Actinidiaceae. To better understand the molecular basis of the <i>Actinidia arguta</i> chloroplast (cp), we sequenced the complete cp genome from <i>A</i>. <i>arguta</i> using Illumina and PacBio RS II sequencing technologies. The cp genome from <i>A</i>. <i>arguta</i> was 157,611 bp in length and composed of a pair of 24,232 bp inverted repeats (IRs) separated by a 20,463 bp small single copy region (SSC) and an 88,684 bp large single copy region (LSC). Overall, the cp genome contained 113 unique genes. The cp genomes from <i>A</i>. <i>arguta</i> and three other <i>Actinidia</i> species from GenBank were subjected to a comparative analysis. Indel mutation events and high frequencies of base substitution were identified, and the <i>accD</i> and <i>ycf2</i> genes showed a high degree of variation within <i>Actinidia</i>. Forty-seven simple sequence repeats (SSRs) and 155 repetitive structures were identified, further demonstrating the rapid evolution in <i>Actinidia</i>. The cp genome analysis and the identification of variable loci provide vital information for understanding the evolution and function of the chloroplast and for characterizing <i>Actinidia</i> population genetics.</p></div

Analysis of simple sequence repeats (SSRs) in the <i>A</i>. <i>arguta</i> chloroplast genome.

<p>(A) Presence of SSRs in the LSC, SSC, and IR regions. (B) Frequency of identified SSR motifs of different repeat types.</p

Analysis of repeat sequences in the <i>A</i>. <i>arguta</i> chloroplast genome.

<p>(A) Numbers of different repeat types detected in <i>A</i>. <i>arguta</i>. (B) Distribution of repeat sequences in the chloroplast genome.</p

Phylogenetic tree reconstructed from the complete chloroplast genome sequences from forty-one species.

<p>Numbers above the lines represent the ML bootstrap values.</p

SSR sequences in the <i>Actinidia arguta</i> chloroplast genome.

<p>The SSR-containing coding regions are indicated in parentheses.</p

<i>A</i>. <i>arguta</i> (Actinidiaceae) genome map.

<p>Genes shown outside the outer circle are transcribed clockwise, while those inside are transcribed counterclockwise. Genes belonging to different functional groups are color coded. The dashed area in the inner circle indicates the GC content of the chloroplast genome.</p

Visualization of the alignment of three chloroplast genome sequences.

<p><i>A</i>. <i>chinensis</i> was used as the reference sequence. The vertical scale indicates the identity percentage, which ranges from 50 to 100%. The horizontal axis indicates the coordinates within the chloroplast genome. Annotated genes are displayed along the top.</p

Presence of SNPs and indels between <i>A</i>. <i>arguta</i> and other <i>Actinidia</i> species.

<p>Presence of SNPs and indels between <i>A</i>. <i>arguta</i> and other <i>Actinidia</i> species.</p