Trinitro-orcinolate and Trinitro-resorcinate - Sensitivity Trends in Nitroaromatic Energetic Materials

5-Methyl-2,4,6-trinitrobenzene-1,3-diol (trinitro-orcinol, H2TNO) as a close structural relative to the well-known energetic materials trinitroresorcinol (styphnic acid) and trinitrotoluene (TNT) is prepared in high purity and analyzed concerning its vapor pressure using the transpiration method. Several energetic coordination compounds (ECCs) of its respective anion were produced and compared with structurally close styphnate complexes to give an insight into physiochemical trends of the ECC. The synthesized compounds were further analyzed by elemental analysis, IR spectroscopy, differential thermal analysis and low temperature X-ray diffraction analysis. To classify the reported compounds among the energetic materials, they were tested for their sensitivities towards mechanical stimuli such as impact, friction and electrostatic discharge as well as their behavior towards flame

Synthesis of Bridged Tetrazoles with Promising Properties and Potential Applications by a One‐Step Finkelstein Reaction

Numerous nitramine bridged compounds which show promising combinations of properties have already been identified in the area of energetic materials. In this work, four new nitrazapropane bridged tetrazoles, as well as four new trinitrazaheptane tetrazoles and three oxapropane bridged tetrazoles were synthesized and fully characterized. These new compounds can all be synthesized by a simple, one-step synthesis using Finkelstein conditions. All of these new energetic materials were characterized using NMR spectroscopy, single crystal X-ray diffraction, vibrational analysis and elemental analysis. The thermal behaviour of these compounds was studied by differential thermal analysis (DTA) and partly by thermogravimetric analysis (TGA). The BAM standard method was used to determine the sensitivities towards impact (IS) and friction (FS). The enthalpies of formation were calculated at the CBS-4M level, and the energetic performances were calculated using the EXPLO5 (V6.06.01) computer code. The properties of the new compounds were compared to each other as well as to the known energetic material RDX. Moreover, the iron(II) and copper(II) perchlorate complexes with 1,3-bis-1,1-tetrazolylnitrazapropane as ligand were prepared and investigated

Evolutionary winners are ecological losers among oceanic island plants

Aim Adaptive radiation, in which successful lineages proliferate by exploiting untapped niche space, provides a popular but potentially misleading characterization of evolution on oceanic islands. Here we analyse the respective roles of members of in situ diversified vs. non-diversified lineages in shaping the main ecosystems of an archipelago to explore the relationship between evolutionary and ecological ‘success’. Location Canary Islands. Taxon Vascular plants. Methods We quantified the abundance/rarity of the native flora according to the geographical range (number of islands where present and geographical extent of the range), habitat breadth (climatic niche) and local abundance (cover) using species distribution data based on 500 × 500 m grid cells and 2000 vegetation inventories located all over the archipelago. Results Species of diversified lineages have significantly smaller geographic ranges, narrower climatic niches and lower local abundances than those of non-diversified lineages. Species rarity increased with the degree of diversification. The diversified Canarian flora is mainly comprised by shrubs. At both archipelagic and island level, the four core ecosystems (Euphorbia scrub, thermophilous woodlands, laurel forest and pine forest) were dominated by non-diversified lineages species, with diversified lineages species providing <25% cover. Species of diversified lineages, although constituting 54% of the archipelagic native flora, were only abundant in two rare ecosystems: high mountain scrub and rock communities. Main conclusions Radiated species, endemic products of in situ speciation, are mostly rare in all three rarity axes and typically do not play an important role in structuring plant communities on the Canaries. The vegetation of the major ecosystem types is dominated by plants representing non-diversified lineages (species that derive from immigration and accumulation), while species of evolutionarily successful lineages are abundant only in marginal habitats and could, therefore, be considered ecological losers. Within this particular oceanic archipelago, and we posit within at least some others, evolutionary success in plants is accomplished predominantly at the margins.publishedVersio

Morphological investigations on carbon black particles by atomic force microscopy

Abstract The atomic force microscope (AFM) can profile surfaces similar to the scanning tunneling microscope (STM) at resolutions down to the atomic level. To investigate carbon-black particles and subsequently styrene-butadiene-rubber, filled with carbon black, a STM was modified to run as an AFM. An optical detection system is used to measure the deflection of the cantilever. Atomic resolution was achieved by forces in the order of 5·10−8 N on mica with the AFM. Structural investigations of carbon-black particles of different dimensions with the AFM agree with the data of the manufacturer. The model of the microstructure of such particles, built up of 1–3 nm large, tilted domains of graphite structures, could be confirmed. This surface roughness is probably an important parameter for the strengthening mechanism of carbon black in elastomers.</jats:p

Synthesis and Characterization of the Energetic Compounds Aminoguanidinium-, Triaminoguanidiniumand Azidoformamidinium Perchlorate

Aminoguanidinium perchlorate (2, AGClO4) was formed by the reaction of aminoguanidinium bicarbonate (1) with aqueous perchloric acid solution. Triaminoguanidinium perchlorate (3, TAGClO4) was synthesized by nucleophilic attack of aqueous hydrazine solution on aminoguanidinium perchlorate under release of ammonia. The new and highly explosive azidoformamidinium perchlorate (4, AFClO4) was formed by the reaction of aminoguanidinium perchlorate with potassium nitrite under acidic conditions. The structures of the perchlorate salts in the crystalline state were determined using low temperature single crystal X-ray diffraction yielding monoclinic as well as orthorhombic structures. The compounds were characterized comprehensively using vibrational spectroscopy (IR and Raman), multinuclear (1H, 13C and 15N) NMR spectroscopy, elemental analysis and mass spectrometry. The thermal behavior as well as the decompositions were investigated using DSC (differential scanning calorimetry) and the heats of formation were calculated using heats of combustion determined by bomb calorimetric measurements. In addition, the sensitivities were evaluated using BAM methods (drophammer and friction tester), whereby the perchlorate salts are all sensitive towards impact as well as friction

Correspondence of gradual developmental increases of expression of galectin-reactive glycoconjugates with alterations of the total contents of the two differentially regulated galectins in chicken intestine and liver as indication for overlapping function

The duplication of genes for recognition molecules and the ensuing diversification of the members of such families generate complex groups of homologous proteins. One example are galactosidespecific lectins whose sequences display constant features related to sugar binding, the galectins. Based on the inverse abundance of the chicken galectins CG-14 and CG-16 in adult intestine and liver, these two lectins represent a model to comparatively study expression of the related proteins and the galectin-reactive sites (glycoproteins and glycolipids) biochemically and histochemically. Functional overlap andtor acquisition of distinct functions would be reflected in qualitative andlor quantitative aspects of ligand display. Using five different stages of embryogenesis, differential regulation of the two galectins was detected in liver and intestine. The clear preference for one galectin (CC-14) was observed in intestine already at rather early stages, whereas equivalence for both proteins was noted in liver from day 12 to day 18 prior to hatching, as seen by ELISA assays and Western blot analysis. Presentation of galectin-reactive glycoproteins showed a tendency for gradual increase in both organs. Galectin-blotting analysis revealed primarily very similar patterns of positive bands at the different stages of development and only few quantitative and qualitative changes. The reactivity of glycolipids in a solid-phase assay was more variable, even surpassing the response of extracts of the adult organ at several embryonic stages. While the localization patterns of the galectins and galectinreactive sites were nearly indistinguishable in the liver, intestinal tissue differed with respect to the placement and accessibility of binding sites. Thus, the results suggest a differential regulation of galectin activities in the two organs. As a sum they resemble the course of development of availability of glycoprotein ligands in vitro. These findings support the notion for a partial functional redundancy in this family. The described approach to employ galectin-specific antibodies and the labeled galectins as tools to assess presentation of ligands is suggested to be of general relevance to address the question of distinct vs. overlapping functions of related recognition molecules

Highly Energetic Salts of 3,6-Bishydrazino-1,2,4,5-tetrazine

3,6-Bishydrazino-1,2,4,5-tetrazine was synthesized as described by hydrazinolysis of 3,6-bis-(3,5-dimethylpyrazolyl)-1,2,4,5-tetrazine. Doubly protonated 1:1 and 1:2 salts of the highly energetic anions were synthesized. These are bishydrazinium-tetrazine dichloride dihydrate (1:2) (BHT-2HCl•2H2O) (2), bishydrazinium-tetrazine (5,5´-azotetrazolate) dihydrate (1:1) (BHT-ATz•2H2O) (3), bishydrazinium-tetrazine bis (3,5-dinitrotriazolate) dihydrate (1:2) (BHT(DNT)2•2H2O) (4), bishydrazinium-tetrazine bis (5-nitrotetrazolate) (1:2) (BHT(NT)2) (5), bishydrazinium-tetrazine (5,5´-bistetrazolate) dihydrate (1:1) (BHTBT•2H2O) (6), bishydrazinium-tetrazine bistetrazolylamine (1:1) (BHT-BTA) (7), bishydrazinium-tetrazine bis (3-amino-5-nitrotriazolate) (1:2) (BHT-(ANTA)2) (8) and bishydrazinium-tetrazine 4,4´,5,5´-tetranitro-2,2´-bisimidazolate (1:1) (9). Compounds 2-6 could be characterized by low temperature X-ray diffraction. All of the compounds were suffciently analyzed by 1H and {1H}13C and 14N NMR spectroscopy, elemental analysis (CHN), mass spectroscopy (FAB)) and vibrational spectroscopy (IR and Raman). The detonation parameters of the most promising candidates 5 and 9 in terms of energetic applications were calculated using the EXPLO5 V5.05 computer code. The energies of formation were calculated using CBS-4M electronic enthalpies and the atomization method. Furthermore, since all of the compounds are energetic materials, sensitivity tests towards impact (IS), friction (FS) and electrostatical discharge (ESD) were carried out. In addition their thermal stabilities were determined using a differential scanning calorimeter with a heating rate of 5 °C min-1

Hydrazinium 5-Aminotetrazolate: an Insensitive Energetic Material Containing 83.72% Nitrogen

Hydrazinium 5-aminotetrazolate (2) was synthesized via two facile routes. Both the reaction of 5-amino-1H-tetrazole (1) with hydrazine hydrate in aqueous solution and the reaction of 1 with diluted hydrazine solution in THF yield 2 in excellent purities and yields. 2 was characterized comprehensively by X-ray diffraction, IR, Raman and multinuclear NMR spectroscopy, mass spectrometry, elemental analysis and differential scanning calorimetry. The heat of formation was calculated (CMS-4M) using the atomization method to be 373 kJ mol-1. With this value and the X-ray density several detonation parameter (heats of explosion, detonation pressure, detonation velocity, explosion temperature) were calculated with the EXPLO5 computer software. An incredible high value (9516 m s-1) was obtained for the detonation velocity. Therefore experimentally tests to determine the velocity of detonation were performed. In addition the use of 2 in solid propellant compositions was calculated and tested in combination with oxidizers, e.g. ammonium dinitramide. Lastly the sensitivities towards impact, friction and electrostatic discharge were determined with the BAM drophammer, friction tester and an ESD machine