J. Appl. Cryst.の発刊に際して

Ultralight (<10 milligrams per cubic centimeter) cellular materials are desirable for thermal insulation; battery electrodes; catalyst supports; and acoustic, vibration, or shock energy damping. We present ultralight materials based on periodic hollow-tube microlattices. These materials are fabricated by starting with a template formed by self-propagating photopolymer waveguide prototyping, coating the template by electroless nickel plating, and subsequently etching away the template. The resulting metallic microlattices exhibit densities ρ ≥ 0.9 milligram per cubic centimeter, complete recovery after compression exceeding 50% strain, and energy absorption similar to elastomers. Young’s modulus E scales with density as E ~ ρ^2, in contrast to the E ~ ρ^3 scaling observed for ultralight aerogels and carbon nanotube foams with stochastic architecture. We attribute these properties to structural hierarchy at the nanometer, micrometer, and millimeter scales.

Ultralight Metallic Microlattices

The article describes a classification system termed "extended functional groups" (EFG), which are an extension of a set previously used by the CheckMol software, that covers in addition heterocyclic compound classes and periodic table groups. The functional groups are defined as SMARTS patterns and are available as part of the ToxAlerts tool (http://ochem.eu/alerts) of the On-line CHEmical database and Modeling (OCHEM) environment platform. The article describes the motivation and the main ideas behind this extension and demonstrates that EFG can be efficiently used to develop and interpret structure-activity relationship models.

https://www.mdpi.com/1420-3049/21/1/1/pdf

Extended Functional Groups (EFG): An Efficient Set for Chemical Characterization and Structure-Activity Relationship Studies of Chemical Compounds

http://www.sciencemadness.org/talk/files.php?pid=302583&aid=26587

Azole-based energetic salts.

Advances in science and technology of modern energetic materials: an overview.

3,3′‐Azobis(6‐amino‐1,2,4,5‐tetrazine): A Novel High‐Nitrogen Energetic Material

The synthesis, characterization, and energetic properties of diazido heteroaromatic high-nitrogen C-N compound, 3,6-diazido-1,2,4,5-tetrazine (DiAT), are reported. Its normalized heat of formation (NDeltaHf), experimentally determined using an additive method, is shown to be the highest positive NDeltaHf compared to all other organic molecules. The unexpected azido-tetrazolo tautomerizations and irreversible tetrazolo transformation of DiAT are remarkable compared to all other polyazido heteroaromatic high-nitrogen C-N compounds, for example, 2,4,6-triazido-1,3,5-triazine; 4,4',6,6'-tetra(azido)hydrazo-1,3,5-triazine; 4,4',6,6'-tetra(azido)azo-1,3,5-triazine; and 2,5,8-tri(azido)-1,3,4,6,7,9,9b-heptaazaphenalene (heptazine).

Synthesis, characterization, and energetic properties of diazido heteroaromatic high-nitrogen C-N compound.

The synthesis and properties of several new energetic 1,2,4,5-tetrazine derivatives are described. These include energetic salts of 3,6-dihydrazino-1,2,4,5-tetrazine and several symmetrically and unsymmetrically substituted tetrazines with energetic substituents, in addition to a new nitro-tetrazine.

1,2,4,5-tetrazine based energetic materials

The synthesis of low-density, nanoporous materials has been an active area of study in chemistry and materials science dating back to the initial synthesis of aerogels. These materials, however, are most often limited to metal oxides, e.g., silica and alumina, and organic aerogels, e.g., resorcinol/formaldehyde, or carbon aerogels, produced from the pyrolysis of organic aerogels. The ability to form monolithic metallic nanocellular porous materials is difficult and sometimes elusive using conventional methodology. Here we report a relatively simple method to access unprecedented ultralow-density, nanostructured, monolithic, transition-metal foams, utilizing self-propagating combustion synthesis of novel transition-metal complexes containing high nitrogen energetic ligands. During the investigation of the decomposition behavior of the high-nitrogen transition metal complexes, it was discovered that nanostructured metal monolithic foams were formed in a post flame-front dynamic assembly having remarkably low densities down to 0.011 g cm(-3) and extremely high surface areas as high as 270 m(2) g(-1). We have produced monolithic nanoporous metal foams via this method of iron, cobalt, copper, and silver metals. We expect to be able to apply this to many other metals and to be able to tailor the resulting structure significantly.

http://faculty.uca.edu/patrickd/chem4380/litstudy_example.pdf

Ultralow-Density Nanostructured Metal Foams: Combustion Synthesis, Morphology, and Composition

The reaction of 3-amino-5-nitro-1,2,4-triazole with nitrous acid produces the corresponding diazonium salt. When the diazonium salt is treated with nitroacetonitrile, a subsequent condensation and cyclization reaction occurres to produced 4-amino-3,7-dinitrotriazolo-[5,1-c][1,2,4] triazine (DPX-26). X-ray crystallographic analysis shows that the DPX-26 has a density of 1.86 g cm−3, while it is calculated to have a heat of formation of 398.3 kJ mol−1. DPX-26 is predicted to approach the explosive performance of RDX but displays significantly better safety properties. Oxidation of DPX-26 using hypofluorous acid produces 4-amino-3,7-dinitrotriazolo-[5,1-c][1,2,4] triazine 4-oxide (DPX-27), which is also predicted to be a high-performance material with enhanced safety properties.

David E. Chavez

Papers

3,3′‐Azobis(6‐amino‐1,2,4,5‐tetrazine): A Novel High‐Nitrogen Energetic Material

Synthesis, characterization, and energetic properties of diazido heteroaromatic high-nitrogen C-N compound.

1,2,4,5-tetrazine based energetic materials

Ultralow-Density Nanostructured Metal Foams: Combustion Synthesis, Morphology, and Composition

An Energetic Triazolo-1,2,4-Triazine and its N-Oxide