Polymorphism of Energetic Materials: A Comprehensive Study of Molecular Conformers, Crystal Packing, and the Dominance of Their Energetics in Governing the Most Stable Polymorph

2018 ◽  
Vol 18 (7) ◽  
pp. 4174-4186 ◽  
Author(s):  
Guangrui Liu ◽  
Ruijun Gou ◽  
Hongzhen Li ◽  
Chaoyang Zhang
Keyword(s):  
Energetic Materials ◽  
Crystal Packing ◽  
Stable Polymorph ◽  
Comprehensive Study

Energetic materials: α-NTO crystallizes as a four-component triclinic twin

2005 ◽  
Vol 61 (5) ◽  
pp. 577-584 ◽  
Author(s):  
Nadezhda Bolotina ◽  
Kristin Kirschbaum ◽  
A. Alan Pinkerton
Keyword(s):  
Energetic Materials ◽  
Crystal Packing ◽  
Energetic Material ◽  
Data Sets ◽  
Flat Chain ◽  
Planar Molecules ◽  
Triclinic Unit Cell ◽  
Symmetry Space ◽  
Symmetry Space Group ◽  
Additional Hydrogen

The prevalent polymorph of the energetic material 5-nitro-2,4-dihydro-1,2,4,-triazol-3-one, α-NTO, crystallizes as a four-component twin with triclinic symmetry (space group P\bar 1). All crystals under investigation were fourlings, i.e. they contained each of the four possible twin components. Complete data sets were collected for two crystals, one with a predominant amount of one individual component (55%) and one with approximately equal volumes of each component. In both cases the fourling components are related by the twofold axes inherent in the holohedral symmetry of a pseudo-orthorhombic superlattice with a o = a t , b o = b t and c o = a t + b t + 2c t . The triclinic unit cell contains four crystallographically independent planar molecules in the asymmetric unit, each of which forms a hydrogen-bonded flat chain parallel to a t . Pairs of chains are combined into planar ribbons by additional hydrogen bonds. Thus, two independent ribbons extend parallel to a t , creating a dihedral angle of ∼ 70°. The origin of the twinning is derived from consideration of the crystal packing and the hydrogen-bonding scheme.

scholarly journals Computational Study on Substituteds-Triazine Derivatives as Energetic Materials

2012 ◽  
Vol 9 (2) ◽  
pp. 583-592 ◽  
Author(s):  
Vikas D. Ghule ◽  
S. Radhakrishnan ◽  
Pandurang M. Jadhav ◽  
Surya P. Tewari
Keyword(s):  
Thermal Stability ◽  
Energetic Materials ◽  
Density Functional ◽  
Crystal Packing ◽  
Computational Study ◽  
Heats Of Formation ◽  
Dissociation Energies ◽  
The Density Functional Theory ◽  
Triazine Derivatives ◽  
Derivatives Of

s-Triazine is the essential candidate of many energetic compounds due to its high nitrogen content, enthalpy of formation and thermal stability. The present study explores s-triazine derivatives in which different -NO2, -NH2and -N3substituted azoles are attached to the triazine ring via C-N linkage. The density functional theory is used to predict geometries, heats of formation and other energetic properties. Among the designed compounds, -N3derivatives show very high heats of formation. The densities for designed compounds were predicted by using the crystal packing calculations. Introduction of -NO2group improves density as compared to -NH2and -N3, their order of increasing density can be given as NO2>N3>NH2. Analysis of the bond dissociation energies for C-NO2, C-NH2and C-N3bonds indicates that substitutions of the -N3and -NH2group are favorable for enhancing the thermal stability ofs-triazine derivatives. The nitro and azido derivatives of triazine are found to be promising candidates for the synthetic studies.

Relationship between the crystal packing and impact sensitivity of energetic materials

CrystEngComm ◽  
2018 ◽  
Vol 20 (6) ◽  
pp. 837-848 ◽  
Author(s):  
Beibei Tian ◽  
Ying Xiong ◽  
Lizhen Chen ◽  
Chaoyang Zhang
Keyword(s):  
Crystal Engineering ◽  
Energetic Materials ◽  
Crystal Packing ◽  
Impact Sensitivity ◽  
Packing Structure ◽  
High Concern

The crystal packing structure–safety (usually represented by sensitivity) relationships of energetic materials (EMs) are requisite to set a basis for tailoring new ones with the desired safety by means of crystal engineering, because safety is one of the two most important properties of EMs for which there is always a high concern.

A DFT study of five-membered nitrogen-containing fused heterocycles for insensitive highly energetic materials

RSC Advances ◽  
2016 ◽  
Vol 6 (80) ◽  
pp. 77005-77012 ◽  
Author(s):  
Qun Zeng ◽  
Yanyang Qu ◽  
Jinshan Li ◽  
Hui Huang
Keyword(s):  
Hydrogen Bonds ◽  
Energetic Materials ◽  
Crystal Packing ◽  
Dft Study ◽  
Layered Crystal ◽  
Aromatic Rings ◽  
Fused Heterocycles ◽  
Suitable Combination ◽  
Highly Energetic Materials ◽  
New Compounds

A suitable combination of aromatic rings, hydrogen bonds and layered crystal packing can be applied to obtain new compounds with both power and safety aspects.

scholarly journals Comparison between the orthorhombic and tetragonal forms of the heptamer sequence d[GCG(xT)GCG]/d(CGCACGC)

2010 ◽  
Vol 66 (9) ◽  
pp. 1028-1031 ◽  
Author(s):  
Koen Robeyns ◽  
Piet Herdewijn ◽  
Luc Van Meervelt
Keyword(s):  
Dna Sequences ◽  
Crystal Packing ◽  
Building Blocks ◽  
Stable Form ◽  
Complementary Dna ◽  
Naturally Occurring ◽  
Artificial Dna ◽  
Tetragonal Form ◽  
Sugar Ring ◽  
Stable Polymorph

Cyclohexene nucleic acid (CeNA) building blocks can be introduced into natural DNA sequences without a large conformational influence because of the ability of the six-membered sugar ring to mimic both the C2′-endoand C3′-endoconformations of the naturally occurring ribofuranose sugar ring. The non-self-complementary DNA sequence d[GCG(xT)GCG]/d(CGCACGC) with one incorporated CeNA (xT) moiety crystallizes in two forms: orthorhombic and tetragonal. The tetragonal form, which diffracts to 3 Å resolution, is a kinetically stable polymorph of the orthorhombic form [Robeynset al.(2010),Artificial DNA,1, 1–7], which diffracts to 1.17 Å resolution and is the thermodynamically stable form of the CeNA-incorporated duplex. Here, the two structures are compared, with special emphasis on the differences in crystal packing and the irreversible conversion of the kinetic form into the high-resolution diffracting thermodynamic form.

scholarly journals Energetic Co-Crystal of a Primary Metal-Free Explosive with BTF. Ideal Pair for Co-Crystallization

Molecules ◽  
2021 ◽  
Vol 26 (24) ◽  
pp. 7452
Author(s):  
Kyrill Yu. Suponitsky ◽  
Ivan V. Fedyanin ◽  
Valentina A. Karnoukhova ◽  
Vladimir A. Zalomlenkov ◽  
Alexander A. Gidaspov ◽  
...  
Keyword(s):  
Intermolecular Interactions ◽  
Energetic Materials ◽  
Crystal Packing ◽  
Structural Features ◽  
Detonation Pressure ◽  
Structural Units ◽  
Primary Metal ◽  
Before And After ◽  
Improved Performance ◽  
The Impact

Co-crystallization is an elegant technique to tune the physical properties of crystalline solids. In the field of energetic materials, co-crystallization is currently playing an important role in the engineering of crystals with improved performance. Here, based on an analysis of the structural features of the green primary explosive, tetramethylammonium salt of 7-oxo-5-(trinitromethyl)-4,5,6,7-tetrahydrotetrazolo[1,5-a][1,3,5]triazin-5-ide (1), a co-former such as the powerful secondary explosive, benzotrifuroxan (BTF, 2), has been proposed to improve it. Compared to the original 1, its co-crystal with BTF has a higher detonation pressure and velocity, as well as an initiating ability, while the impact sensitivity and thermal stability remained at about the same level. Both co-formers, 1 and 2, and co-crystal 3 were characterized by single-crystal X-ray diffraction and their crystal packing was analyzed in detail by the set of approaches, including periodic calculations. In the co-crystal 3, all intermolecular interactions were significantly redistributed. However, no new types of intermolecular interactions were formed during co-crystallization. Moreover, the interaction energies of structural units in crystals before and after co-crystallization were approximately the same. A similar trend was observed for the volumes occupied by structural units and their densifications. The similar nature of the organization of the crystals of the co-formers and the co-crystal gives grounds to assert that the selected co-formers are an ideal pair for co-crystallization, and the invariability of the organization of the crystals was probably responsible for the preservation of some of their properties.

Customization of the molecular structure to modulate the crystal packing style of energetic materials

2019 ◽  
Vol 4 (5) ◽  
pp. 1032-1038
Author(s):  
Qi Huang ◽  
Zhicheng Guo ◽  
Longyu Liao ◽  
Shilong Hao ◽  
Fude Nie ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Energetic Materials ◽  
Crystal Packing ◽  
Impact Sensitivity ◽  
Pyrazine Ring

The crystal packing style and corresponding impact sensitivity of the dinitro-pyrazine ring have been modulated by customizing the molecular structure.

scholarly journals Charge density studies of nucleobase analogues - the case of DAP and isocytosine

2014 ◽  
Vol 70 (a1) ◽  
pp. C968-C968
Author(s):  
Urszula Budniak ◽  
Katarzyna Jarzembska ◽  
Paulina Dominiak
Keyword(s):  
Nucleic Acids ◽  
Charge Density ◽  
Gas Phase ◽  
Crystal Packing ◽  
Theoretical Calculations ◽  
X Ray Diffraction ◽  
X Ray ◽  
Density Analysis ◽  
Modified Nucleobases ◽  
Comprehensive Study

Nucleobases belong to purine and pyrimidine family and constitute a biologically crucial group of compounds thank to their relation to nucleic acids. Specific interactions between these moieties are responsible for maintaining a proper structure of DNA, namely: hydrogen bonding and π-π stacking interactions (between aromatic ring fragments). Furthermore, many modifications of natural nucleobases serve as drugs, but some could be extremely harmful. In view of the above, investigating the properties of analogues of nucleobases may contribute to our knowledge about nucleic acid properties in general and give an opportunity to find novel ligands binding to DNA, what is essential for drug design. Within this project two modified nucleobases were examined: 2,6-diaminopurine (DAP) and isocytosine (iC). DAP is a derivative of the adenine and iC is an isomer of cytosine. These compounds do not appear naturally in nucleic acids, however, can be used to compare Watson-Crick pairing in DNA and pairing of alternative bases. High resolution X-ray diffraction experiments were carried out to obtain appropriate data for charge density analysis. A comprehensive study of crystal packing and energetic features of the analysed systems was conducted. The nature of intermolecular interactions, structural motifs and crystal packing was analysed via Hirshfeld surface analysis [1], charge density distribution examination, QTAIM (Quantum Theory of Atoms in Molecules) [2] and theoretical calculations (gas phase dimers and periodic). Implications of the observed interactions for biological systems are discussed. This study was supported by the Polish Ministry of Science and Higher Education within the Diamond Grant No DI 2011012441.

Molecular-Shape-Dominated Crystal Packing Features of Energetic Materials

2021 ◽  
Vol 21 (3) ◽  
pp. 1540-1547
Author(s):  
Yingzhe Liu ◽  
Yilin Cao ◽  
Weipeng Lai ◽  
Tao Yu ◽  
Yiding Ma ◽  
...  
Keyword(s):  
Energetic Materials ◽  
Crystal Packing ◽  
Molecular Shape

Progress In The Practical Application Of Automated Image Analysis To Tem Negatives

1977 ◽  
Vol 35 ◽  
pp. 214-217
Author(s):  
F. A. Heckman ◽  
E. Redman ◽  
J.E. Connolly
Keyword(s):  
Image Analysis ◽  
Image Quality ◽  
Exposure Time ◽  
Image Contrast ◽  
Automated Image Analysis ◽  
Practical Application ◽  
Factors Affecting ◽  
High Image Quality ◽  
Qualitative Evidence ◽  
Comprehensive Study

In our initial publication on this subject1) we reported results demonstrating that contrast is the most important factor in producing the high image quality required for reliable image analysis. We also listed the factors which enhance contrast in order of the experimentally determined magnitude of their effect. The two most powerful factors affecting image contrast attainable with sheet film are beam intensity and KV. At that time we had only qualitative evidence for the ranking of enhancing factors. Later we carried out the densitometric measurements which led to the results outlined below.Meaningful evaluations of the cause-effect relationships among the considerable number of variables in preparing EM negatives depend on doing things in a systematic way, varying only one parameter at a time. Unless otherwise noted, we adhered to the following procedure evolved during our comprehensive study:Philips EM-300; 30μ objective aperature; magnification 7000- 12000X, exposure time 1 second, anti-contamination device operating.

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