Constructing Single- or Dual-Layer Biomass Composite Energetic Material through Self-Assembly of Biomass Polyphenol Structural Materials.

High energy and high risk have always restricted the application of materials in the military and civilian fields. To achieve this goal, researchers have studied the structural characteristics and structure-activity relationship of biomass polyphenol material to obtain core-shell biomass polyphenol composite energetic materials through molecular and structural design. The interface structure has a significant impact on the safety performance and thermal stability of energetic materials. The unique advantages of natural biomass polyphenol chemistry (tannic acid and tea polyphenols) include the structural design and performance control of energetic materials. This paper provides a review of the preparation of core-shell biomass polyphenol energetic materials, which involve the use of polyphenols as the shell layer, surface modification layer, and intermediate layer to enhance intermolecular interactions. This approach aims to enhance the thermal stability and reduce the sensitivity. Furthermore, the paper offers suggestions for potential future research directions based on the findings.

Biomass tannic acid modified titanium dioxide nanoparticles enhance desensitization and thermal stability of energetic materials.

Titanium dioxide (TiO2) had the potential to be a desensitizing material, but its inherent characteristics presented challenges for coating on energetic materials. To enhance the interfacial interactions of energetic materials and TiO2, the surface of TiO2 was modified with biomass tannic acid (TA) to prepare the core-shell (hexanitrohexaazaisowurtzitane) CL-20@TA-TiO2 energetic composites. Various characterization techniques were used to investigate the thermal performance, impact sensitivity, structure, and surface morphology of CL-20@TA-TiO2. The protective layer formed by the TA-TiO2 coating on the surface of CL-20, thus protecting the material from external stimulation. The results indicated that the organic-inorganic core-shell energetic composites prepared with biomass TA as the interface layer exhibited outstanding performance.

Visible-Light-Promoted Catalyst-Free Oxyarylation and Hydroarylation of Alkenes with Carbon Dioxide Radical Anion.

Visible-light-mediated oxyarylation and hydroarylation of alkenes with aryl halides using formate salts as the reductant and hydrogen source under ambient conditions were developed. These protocols represent rare catalyst-free examples of the realization of such transformations. Using styrenes as substrates, oxyarylation could occur smoothly. Whereas, hydroarylation proceeds employing electron deficient alkenes. Moreover, dehalogenation proceeds successfully in the absence of alkenes. We expected that this method could provide a valuable strategy for the functionalization of aryl halides.

Visible light-promoted synthesis of ureas and formamides from amines and CO2.

A divergent visible-light-induced Ph3P-promoted method for the synthesis of ureas and formamides from amines and CO2 is reported. Without external additions, a range of ureas could be directly accessed under ambient temperature and pressure. Using triisopropylsilanethiol as the hydrogen source, formamides could be produced.

Theoretical research on cage-like furazan-based energetic compounds and its derivatives.

In this manuscript, we reported the design and prediction of two furazan-based cage-like molecules and their derivatives using density function theory (DFT). The heat formation and detonation properties were calculated using Hess's law and Kamlet-Jacobs equations with the B3PW91 method. The molecular stability and geometry were analyzed using the M06-2X method, and molecular crystal structures were predicted based on Monte Carlo simulation, while chemical reactive sites were judged using the PBE0 method based on Fukui function. The theoretical calculation result proved that the designed molecules exhibit ideal symmetric cage-like geometry and show superior physicochemical and detonation properties. Compared with traditional energetic materials, the designed molecules display more positive solid heat formation and lower sensitivity. The designed molecules could be considered promising high energy density material candidates with potential synthesis and application value. Two designed molecules display superior detonation performance and ideal completely symmetric cage-like geometry, which were proved theoretically as a promising HEDM candidate. A series of derivatives also exhibited excellent crystal density and physicochemical properties, while with more stable structure.

Photoinduced Oxidative Alkoxycarbonylation of Alkenes with Alkyl Formates.

A photoinduced oxidative alkoxycarbonylation of alkenes initiated by intermolecular addition of alkoxycarbonyl radicals has been demonstrated. Employing alkyl formates as alkoxycarbonyl radical sources, a range of α,ß-unsaturated esters were obtained with good regioselectivity and E selectivity under ambient conditions.

Carbonylative coupling of simple alkanes and alkenes enabled by organic photoredox catalysis.

A visible-light-driven direct carbonylative coupling of simple alkanes and alkenes via the combination of a hydrogen atom transfer process and photoredox catalysis has been demonstrated. Employing the N-alkoxyazinium salt as the oxidant and the precursor of an oxygen radical, a variety of α,ß-unsaturated ketones could be obtained in a metal-free fashion.

Visible-Light-Mediated Divergent Silylfunctionalization of Alkenes.

1,2-Silylfunctionalization of alkenes is an efficient way to construct highly functionalized silicon-containing compounds. However, examples of 1,2-silylfunctionalization of alkenes using readily available hydrosilanes are limited. Herein, we present a visible-light-mediated divergent 1,2-silylfunctionalization of alkenes using hydrosilane under ambient conditions. A series of ß-alkoxy, ß-alkylthio, ß-hydroxy, and ß-indolyl silanes was obtained in good to excellent yields. Moreover, vinylsilanes were successfully prepared in the absence of an additional nucleophile.

Theoretical studies on oxadiazole-based layer stacking nitrogen-rich high-performance insensitive energetic materials.

A series of energetic compounds derived from substituted oxadiazole molecules which were theoretically proved to have π-π stacking crystal structure using NIC method and QTAIM theory were designed and investigated theoretically as novel high-performance insensitive energetic materials. The heats of formation (HOFs) and detonation parameters were predicted based on Kamlet-Jacobs equations and Born-Haber cycle. All energetic compounds and derivatives were calculated at DFT-B3PW91/6-31G++(d,p) level and exhibited ideal oxygen balance (OB%) (- 19.50~15.68), positive heats of formation (424.0~957.4 kJ/mol), and pleasant crystal density (1.707~1.901 g/cm3). The predicted results revealed that detonation performances of some designed molecules are equal to traditional energetic materials while they are more stable and insensitive that can be considered to have potential synthesis and application value. Graphical abstract BRIEFS Three energetic molecules that proved may have a π-π stacking crystal structure and its derivatives were designed and investigated theoretical as novel high-performance insensitive energetic materials. The most of compounds exhibited positive solid phase heat of formation, idea oxygen balance and structural stability.

Theoretical investigation of nitrogen-rich high-energy-density materials based on furazan substituted s-triazine.

A series of furazan substituted s-triazine derivatives were designed and investigated theoretically as potential nitrogen-rich high-energy-density materials in this work. Density functional theory (DFT) methods were used to predict the heats of formation (HOFs) and compounds structure was optimized at B3PW91/6-31G++ (d,p) level. The explosive detonation parameters were calculated based on Kamlet-Jacobs equations and Born-Haber cycle. The presence of the -NO2 and - NH2 groups in the same structure were found to be helpful in improving structural stability through intramolecular weak interactions. Most of the designed compounds were characterized by high HOFs (solid-phase heat of information 71.01-518.20 kJ/mol) and crystal density values (1.74-1.90 g/cm3). In the analysis of frontier molecular orbital that some designed compounds chemical activity similar with TATB, but show better detonation performance. The predicted results reveal that some designed nitrogen-rich compounds outperform traditional energetic materials and may be considered as potential candidates for high-energy materials. Graphical Abstract BRIEFS A series of furazan substituted s-triazine derivatives were designed and investigated theoretically as potential nitrogen-rich high-energy-density materials and most of the compounds exhibit high solid phase heat of information and fascinating detonation properties.

Photoredox-Catalyzed α-C(sp3)-H Activation of Unprotected Secondary Amines: Facile Access to 1,4-Dicarbonyl Compounds.

A photoredox-catalyzed α-C(sp3)-H activation approach of unprotected secondary amines is reported. Such transformations provide facile access to various 1,4-dicarbonyl compounds using readily available amines and α,ß-unsaturated compounds as feedstocks under air conditions. The substrate scope of this method is broad, and a wide array of functional groups are tolerated.