Backbone Isomerization to Enhance Thermal Stability and Decrease Mechanical Sensitivities of 10 Nitro-Substituted Bipyrazoles

The development of novel, environmentally friendly, and high-energy oxidizers remains interesting and challenging for replacing halogen-containing ammonium perchloride (AP). The trinitromethyl moiety is one of the most promising substituents for designing high-energy density oxidizers. In this study, a backbone isomerization strategy was utilized to manipulate the properties of 10 nitro group-substituted bipyrazoles containing the largest number of nitro groups among the bis-azole backbones so far. Another advanced high-energy density oxidizer, 3,3′,5,5′-tetranitro-1,1′-bis­(trinitromethyl)-1H,1′H-4,4′-bipyrazole (3), was designed and synthesized. Compared to the isomer 4,4′,5,5′-tetranitro-2,2′-bis­(trinitromethyl)-2H,2′H-3,3′-bipyrazole (4) (Td = 125 °C), 3 possesses better thermostability (Td = 156 °C), which is close to that of ammonium dinitramide (ADN) (Td = 159 °C), and it possesses better mechanical sensitivity (impact sensitivity (IS) = 13 J and friction sensitivity (FS) = 240 N) than that of 4 (IS = 9 J and FS = 215 N), thereby demonstrating a promising perspective for practical applications

Backbone Isomerization to Enhance Thermal Stability and Decrease Mechanical Sensitivities of 10 Nitro-Substituted Bipyrazoles

The development of novel, environmentally friendly, and high-energy oxidizers remains interesting and challenging for replacing halogen-containing ammonium perchloride (AP). The trinitromethyl moiety is one of the most promising substituents for designing high-energy density oxidizers. In this study, a backbone isomerization strategy was utilized to manipulate the properties of 10 nitro group-substituted bipyrazoles containing the largest number of nitro groups among the bis-azole backbones so far. Another advanced high-energy density oxidizer, 3,3′,5,5′-tetranitro-1,1′-bis­(trinitromethyl)-1H,1′H-4,4′-bipyrazole (3), was designed and synthesized. Compared to the isomer 4,4′,5,5′-tetranitro-2,2′-bis­(trinitromethyl)-2H,2′H-3,3′-bipyrazole (4) (Td = 125 °C), 3 possesses better thermostability (Td = 156 °C), which is close to that of ammonium dinitramide (ADN) (Td = 159 °C), and it possesses better mechanical sensitivity (impact sensitivity (IS) = 13 J and friction sensitivity (FS) = 240 N) than that of 4 (IS = 9 J and FS = 215 N), thereby demonstrating a promising perspective for practical applications

Backbone Isomerization to Enhance Thermal Stability and Decrease Mechanical Sensitivities of 10 Nitro-Substituted Bipyrazoles

The development of novel, environmentally friendly, and high-energy oxidizers remains interesting and challenging for replacing halogen-containing ammonium perchloride (AP). The trinitromethyl moiety is one of the most promising substituents for designing high-energy density oxidizers. In this study, a backbone isomerization strategy was utilized to manipulate the properties of 10 nitro group-substituted bipyrazoles containing the largest number of nitro groups among the bis-azole backbones so far. Another advanced high-energy density oxidizer, 3,3′,5,5′-tetranitro-1,1′-bis­(trinitromethyl)-1H,1′H-4,4′-bipyrazole (3), was designed and synthesized. Compared to the isomer 4,4′,5,5′-tetranitro-2,2′-bis­(trinitromethyl)-2H,2′H-3,3′-bipyrazole (4) (Td = 125 °C), 3 possesses better thermostability (Td = 156 °C), which is close to that of ammonium dinitramide (ADN) (Td = 159 °C), and it possesses better mechanical sensitivity (impact sensitivity (IS) = 13 J and friction sensitivity (FS) = 240 N) than that of 4 (IS = 9 J and FS = 215 N), thereby demonstrating a promising perspective for practical applications

Backbone Isomerization to Enhance Thermal Stability and Decrease Mechanical Sensitivities of 10 Nitro-Substituted Bipyrazoles

The development of novel, environmentally friendly, and high-energy oxidizers remains interesting and challenging for replacing halogen-containing ammonium perchloride (AP). The trinitromethyl moiety is one of the most promising substituents for designing high-energy density oxidizers. In this study, a backbone isomerization strategy was utilized to manipulate the properties of 10 nitro group-substituted bipyrazoles containing the largest number of nitro groups among the bis-azole backbones so far. Another advanced high-energy density oxidizer, 3,3′,5,5′-tetranitro-1,1′-bis­(trinitromethyl)-1H,1′H-4,4′-bipyrazole (3), was designed and synthesized. Compared to the isomer 4,4′,5,5′-tetranitro-2,2′-bis­(trinitromethyl)-2H,2′H-3,3′-bipyrazole (4) (Td = 125 °C), 3 possesses better thermostability (Td = 156 °C), which is close to that of ammonium dinitramide (ADN) (Td = 159 °C), and it possesses better mechanical sensitivity (impact sensitivity (IS) = 13 J and friction sensitivity (FS) = 240 N) than that of 4 (IS = 9 J and FS = 215 N), thereby demonstrating a promising perspective for practical applications

(A) The C atoms of all residues involved in binding in any of the five peptide bound structures are shown (red) along with the rest of the backbone (light blue ribbon)

(B) The standard deviation in the area bound on complex formation is displayed by coloring the C atoms of peptide binding residues on a gradient, from a standard deviation of 0Å (blue) to 10Å and greater (red). (C) The backbone RMSF of the 14-3-3 domain calculated over C atoms displayed as a color and radius gradient, from an RMSF of 0Å (blue, 0.25Å) to an RMSF of 2.0Å and greater (red, 2.0Å). (D) The side chain RMSF is displayed by coloring the C atoms of peptide binding residues on a gradient, from a RMSF of 0Å (blue) to an RMSF of 0.50Å and greater (red). All parameters were calculated using all five of the peptide-14-3-3 complexes.<p><b>Copyright information:</b></p><p>Taken from "Flexible nets: disorder and induced fit in the associations of p53 and 14-3-3 with their partners"</p><p>http://www.biomedcentral.com/1471-2164/9/S1/S1</p><p>BMC Genomics 2008;9(Suppl 1):S1-S1.</p><p>Published online 20 Mar 2008</p><p>PMCID:PMC2386051.</p><p></p

Flexible nets: disorder and induced fit in the associations of p53 and 14-3-3 with their partners-7

Tion profiles. These are shown aligned with the side chain RMSF (C) and the backbone RMSF (D) calculated from the five structures of bound 14-3-3ζ. Regions of residues that are highly exposed to solvent in all complex structures are indicated by the blue-shaded regions.<p><b>Copyright information:</b></p><p>Taken from "Flexible nets: disorder and induced fit in the associations of p53 and 14-3-3 with their partners"</p><p>http://www.biomedcentral.com/1471-2164/9/S1/S1</p><p>BMC Genomics 2008;9(Suppl 1):S1-S1.</p><p>Published online 20 Mar 2008</p><p>PMCID:PMC2386051.</p><p></p

Flexible nets: disorder and induced fit in the associations of p53 and 14-3-3 with their partners-9

Ons of p53 represented in structure complexes in PDB are represented by horizontal bars, labeled with the name of the binding partner. For the DBD, the extent of the globular domain is indicated by the light grey box, where the internal horizontal bars indicate regions involved in binding to a particular partner. Post translational modifications sites are represented by vertical ticks. Experimentally characterized regions of disorder (red) and order (blue) are indicated by the horizontal bar. Finally, predictions of disorder (scores > 0.5) and order (scores < 0.5) are shown for two PONDR predictors: VLXT (solid line) and VSL2P (dashed line). All, features are presented to scale, as indicated by the horizontal axis. The p53 interaction partners and post translational modification sites have been adapted from Anderson & Appella [].<p><b>Copyright information:</b></p><p>Taken from "Flexible nets: disorder and induced fit in the associations of p53 and 14-3-3 with their partners"</p><p>http://www.biomedcentral.com/1471-2164/9/S1/S1</p><p>BMC Genomics 2008;9(Suppl 1):S1-S1.</p><p>Published online 20 Mar 2008</p><p>PMCID:PMC2386051.</p><p></p

Flexible nets: disorder and induced fit in the associations of p53 and 14-3-3 with their partners-2

Tion between the components of complexes for each residue in the relevant sequence region of p53. The two hatched bars indicate acetylated lysine residues.<p><b>Copyright information:</b></p><p>Taken from "Flexible nets: disorder and induced fit in the associations of p53 and 14-3-3 with their partners"</p><p>http://www.biomedcentral.com/1471-2164/9/S1/S1</p><p>BMC Genomics 2008;9(Suppl 1):S1-S1.</p><p>Published online 20 Mar 2008</p><p>PMCID:PMC2386051.</p><p></p

(A) Sequence alignment of the bound peptides and the RMSF of their conformations

Solid grey bars give the RMSF for four peptides – excluding R18 – and the hatched bars give the RMSF for all five peptides. (B) Aligned ribbon representations of the structures of the five peptides, which were aligned through multiple alignment of their respectively bound 14-3-3 domains, show along with a representative ribbon representation of a 14-3-3 domain.<p><b>Copyright information:</b></p><p>Taken from "Flexible nets: disorder and induced fit in the associations of p53 and 14-3-3 with their partners"</p><p>http://www.biomedcentral.com/1471-2164/9/S1/S1</p><p>BMC Genomics 2008;9(Suppl 1):S1-S1.</p><p>Published online 20 Mar 2008</p><p>PMCID:PMC2386051.</p><p></p

Flexible nets: disorder and induced fit in the associations of p53 and 14-3-3 with their partners-4

The p53 DBD shown in Figure . These are shown aligned with the side chain RMSF (C) and the backbone RMSF (D) calculated from the four structures of bound p53 DBD. Regions of residues that are highly exposed to solvent in all complex structures are indicated by the blue-shaded regions.<p><b>Copyright information:</b></p><p>Taken from "Flexible nets: disorder and induced fit in the associations of p53 and 14-3-3 with their partners"</p><p>http://www.biomedcentral.com/1471-2164/9/S1/S1</p><p>BMC Genomics 2008;9(Suppl 1):S1-S1.</p><p>Published online 20 Mar 2008</p><p>PMCID:PMC2386051.</p><p></p