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1. Taming nitroformate through encapsulation with nitrogen-rich hydrogen-bonded organic frameworks

   https://doi.org/10.1038/s41467-021-22475-8  

   Zhang, Jichuan; Feng, Yongan; Staples, Richard J.; Zhang, Jiaheng; Shreeve, Jean’ne M. (December 2021, Nature Communications)

   null (Ed.)

   Abstract Owing to its simple preparation and high oxygen content, nitroformate [ − C(NO 2 ) 3 , NF] is an extremely attractive oxidant component for propellants and explosives. However, the poor thermostability of NF-based derivatives has been an unconquerable barrier for more than 150 years, thus hindering its application. In this study, the first example of a nitrogen-rich hydrogen-bonded organic framework (HOF-NF) is designed and constructed through self-assembly in energetic materials, in which NF anions are trapped in pores of the resulting framework via the dual force of ionic and hydrogen bonds from the strengthened framework. These factors lead to the decomposition temperature of the resulting HOF-NF moiety being 200 °C, which exceeds the challenge of thermal stability over 180 °C for the first time among NF-based compounds. A large number of NF-based compounds with high stabilities and excellent properties can be designed and synthesized on the basis of this work. 

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2. Thermoelectric Characteristics of Graphene and Aluminum Doped Zinc Oxide Nanopowder Enhanced Cement Composite for Low-Temperature Applications

   Liu, X.; Qu, M. (June 2021, ASHRAE Annual Conference papers)

   Thermoelectric (TE) cement composite is a new type of TE material. Unlike ordinary cement, due to the inclusion of additives, TE cement can mutually transform thermal energy into electrical energy. In extreme weather, the large temperature difference between indoor and outdoor can be harvested by TE cement to generate electricity. In moderate weather, given power input, the same material can provide cooling/heating to adjust room temperature and reduce HAVC load. Therefore, TE cement has energy-saving potential in the application of building enclosures and energy systems. Its ability to convert different forms of energy and use low-grade energy is conducive to the operation of net-zero buildings. In this study, the graphene nanoplatelets and aluminum-doped zinc oxide nanopowder enhanced cement composite, was fabricated. The performance indicator of TE materials includes the dimensionless figure of merit ZT, calculated by Seebeck coefficient, thermal conductivity, and electrical conductivity. These TE properties were measured and calculated by a Physical Property Measurement System at different temperatures. The highest ZT of 15wt.% graphene and 5wt.% AZO enhanced cement composite prepared by the dry method is about 5.93E-5 at 330K. 

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3. Engineering bistetrazoles: ( E )-5,5′-(ethene-1,2-diyl)bis(1 H -tetrazol-1-ol) as a new planar high-energy-density material

   https://doi.org/10.1039/d2ma00664b  

   Singh, Jatinder; Staples, Richard J.; Shreeve, Jean'ne M. (July 2022, Materials Advances)

   Energetic properties of bistetrazole derivatives are improved by the step-by-step introduction of functionalities which improve heat of formation, density, and oxygen content. The incorporation of unsaturation between bis(1 H -tetrazol-5-yl) and bis(1 H -tetrazol-1-ol) derivatives leads to planarity which enhances the density of the final product. In this manuscript, we have synthesized compounds 1,2-di(1 H -tetrazol-5-yl)ethane (4), ( E )-1,2-di(1 H -tetrazol-5-yl)ethene (5), and ( E )-5,5′-(ethene-1,2-diyl)bis(1 H -tetrazol-1-ol), (6) using readily available starting materials. Their corresponding dihydroxylammonium salts 7, 8 and 9 are obtained by reacting two equivalents of hydroxylamine (50% in water). New compounds are analyzed using IR, EA, DSC and multinuclear NMR spectroscopy ( 1 H, 13 C and 15 N). The solid-state structures of compounds 6, 7, 8 and 9 are confirmed by single-crystal X-ray diffraction. The energetic performances are calculated using the EXPLO5 (v6.06.02) code and the sensitivities towards external stimuli such as friction and impact are determined according to BAM standard. Compound 6 {( E )-5,5′-(ethene-1,2-diyl)bis(1 H -tetrazol-1-ol)} exhibits a surprisingly high density of 1.91 g cm −3 at 100 K (1.86 g cm −3 at 298 K). Its detonation velocity (9017 m s −1 ) is considerably superior to those of RDX (8795 m s −1 ), which suggests it is a competitive high-energy-density material. 

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4. Rational design of elastin-like polypeptide fusion proteins to tune self-assembly and properties of protein vesicles

   https://doi.org/10.1039/D3TB00200D  

   Li, Yirui; Dautel, Dylan R.; Gray, Mikaela A.; McKenna, Michael E.; Champion, Julie A. (June 2023, Journal of Materials Chemistry B)

   Protein vesicles made from bioactive proteins have potential value in drug delivery, biocatalysis, and as artificial cells. As the proteins are produced recombinantly, the ability to precisely tune the protein sequence provides control not possible with polymeric vesicles. The tunability and biocompatibility motivated this work to develop protein vesicles using rationally designed protein building blocks to investigate how protein sequence influences vesicle self-assembly and properties. We have reported an elastin-like polypeptide (ELP) fused to an arginine-rich leucine zipper (ZR) and functional, globular proteins fused to a glutamate-rich leucine zipper (ZE) that self-assemble into protein vesicles when warmed from 4 to 25 °C due to the hydrophobic transition of ELP. Previously, we demonstrated the ability to tune vesicle properties by changing protein and salt concentration, ZE:ZR ratio, and warming rate. However, there is a limit to the properties that can be achieved via assembly conditions. In order to access a wider range of vesicle diameter and stability profiles, this work investigated how modifiying the hydrophobicity and length of the ELP sequence influenced self-assembly and the final properties of protein vesicles using mCherry as a model globular protein. The results showed that both transition temperature and diameter of protein vesicles were inversely correlated to the ELP guest residue hydrophobicity and the number of ELP pentapeptide repeats. Additionally, sequence manipulation enabled assembly of vesicles with properties not accessible by changes to assembly conditions. For example, introduction of tyrosine at 5 guest residue positions in ELP enabled formation of nanoscale vesicles stable at physiological salt concentration. This work yields design guidelines for modifying the ELP sequence to manipulate protein vesicle transition temperature, size and stability to achieve desired properties for particular biofunctional applications. 

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5. Functionalized planar aromatic rings as precursors to energetic N , N ′-(4,6-dinitro-1,3-phenylene)dinitramide and its salts

   https://doi.org/10.1039/d2qm00092j  

   Singh, Jatinder; Lal, Sohan; Staples, Richard J.; Shreeve, Jean’ne M. (March 2022, Materials Chemistry Frontiers)

   Functionalization of planar aromatic rings is very straightforward, up scalable, and economical in comparison with many azole, caged, linear or cyclic structures. In our present work, a facile synthesis of N , N ′-(4,6-dinitro-1,3-phenylene)dinitramide (3) is obtained by a single-step nitration of 4,6-dinitrobenzene-1,3-diamine (2). Compound 3 exhibits a surprisingly high density of 1.90 g cm −3 at 100 K (1.87 g cm −3 at 298 K). Its reactions with bases result in the formation of a series of energetic salts (4–7) which exhibit relatively high densities (1.74 to 1.83 g cm −3 ), and acceptable thermal sensitivities (177 to 253 °C). Energetic salt formation increases intermolecular hydrogen bonding while the planarity of the aromatic ring maximizes weak non-covalent interactions (π-stacking, cation/π, anion-π, X-H/π, etc. ,). The synergetic effect of these stabilizing interactions plays a crucial role in increasing thermal stability and decreasing sensitivity toward the external stimuli. Overall, these easily accessible new energetic compounds exhibit high densities and good denotation properties with potential applications as new high-energy materials. 

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