Organic Ligand Exchange: The Chiral Structure-Property Regulation of Cuprous Halides.

The strategy of organic ligand exchange is proposed to tune the optical properties of organic-inorganic hybrid cuprous halides. In this work, the chiral ligand (S)-(-)-2,2'-bis(di--tolylphosphino)-1,1'-binaphthyl ((S)-Tol-BINAP) and achiral triphenylphosphine (PPh) are introduced into cuprous halides CuX-PPh-[(S)-Tol-BINAP] (X = Cl, Br, I) through organic ligand exchange. As a result, the mixed organic ligands can enhance second harmonic generation (SHG) and aggregation-induced emission (AIE) optical properties.

Dopant effect on the optical and thermal properties of the 2D organic-inorganic hybrid perovskite (HDA)PbBr.

Lead-based two-dimensional organic-inorganic hybrid perovskites (2D HOIPs) are popular materials with various optical properties, which can be tuned through metal ion doping. Due to the size and valence misfit, metal ion dopants in 2D lead-based HOIPs are still limited. In this work, Mn, Sb and Bi are doped into 2D (HDA)PbBr (HDA = protonated dopamine) successfully.

Decomposition mechanism of 1,3,5-trinitro-2,4,6-trinitroaminobenzene under thermal and shock stimuli using ReaxFF molecular dynamics simulations.

To obtain atomic-level insights into the decomposition behavior of 1,3,5-trinitro-2,4,6-trinitroaminobenzene (TNTNB) under different stimulations, this study applied reactive molecular dynamics simulations to illustrate the effects of thermal and shock stimuli on the TNTNB crystal. The results show that the initial decomposition of the TNTNB crystal under both thermal and shock stimuli starts with the breakage of the N-NO bond. However, the C ring in TNTNB undergoes structural rearrangement to form a C-C bicyclic structure at a constant high temperature.

Mussel-Inspired Two-Dimensional Halide Perovskite Facilitated Dopamine Polymerization and Self-Adhesive Photoelectric Coating.

Polydopamine (PDA) is a good adhesion agent for lots of gels inspired by the mussel, whereas hybrid organic-inorganic perovskites (HOIPs) usually exhibit extraordinary optoelectronic performance. Herein, mussel-inspired chemistry has been integrated with two-dimensional HOIPs first, leading to the preparation of new crystal (HDA)PbBr () (DA = dopamine). The organic cation dopamine can be introduced into PDA resulting in a thin film of (HPDA)PbBr ().

Evaluation of the efficacy of ipsilateral fibular transfer for reconstruction of large tibial defects in children: a retrospective study.

Background: Reconstruction of large tibial defects is often a major challenge in limb salvage. This study aimed to evaluate initial follow-up results of ipsilateral fibula transfer for the treatment of large tibial defects in children.

Methods: A retrospective study was performed between September 2014 and April 2021.

Clinical significance of signet ring cells in surgical esophageal and esophagogastric junction adenocarcinoma: A systematic review and meta-analysis.

Background: The clinical significance of signet ring cells (SRCs) in surgical esophageal and esophagogastric junction adenocarcinoma (EEGJA) remains unclear now.

Aim: To explore the association between the presence of SRCs and the clinicopathological and prognostic characteristics in surgical EEGJA patients by combining and analyzing relevant studies.

Methods: The PubMed, Web of Science, and EMBASE electronic databases were searched for the relevant literature up to March 28, 2021.

Atomic perspective revealing for combustion evolution of nitromethane/nano-aluminum hydride composite.

Adding aluminum hydride (AlH) into energetic materials (EMs) can improve their combustion and energy performance effectively. However, the potential mechanism of AlH on EMs is still unclear. Based on the ReaxFF-lg method, the thermal decomposition of nitromethane/nano-aluminum hydride (NM/nano-AlH) composites were studied.

Encapsulating aluminum nanoparticles into carbon nanotubes for combustion: a molecular dynamics study.

Metal nanoparticles are easily deactivated by migration-aggregation in combustion. Encapsulated nanoparticles are one of the tools for coping with the stability challenges of metal nanoparticles. The self-assembly details of aluminum nanoparticles (ANPs) encapsulated into carbon nanotubes (CNTs) were demonstrated by molecular dynamics simulations.

Enantioselective synthesis of 3-aryl-phthalides through a nickel-catalyzed stereoconvergent cross-coupling reaction.

A nickel-catalyzed asymmetric Suzuki-Miyaura cross-coupling of racemic 3-bromo-phthalides and arylboronic acids was realized for the synthesis of diverse chiral 3-aryl-phthalides in moderate to excellent reaction yields. The reaction proceeded in a stereoconvergent manner and high enantioselectivities were observed for most examined examples. A number of functional groups like aldehyde, ester and bromide were well tolerated.

Reactive molecular dynamics simulation of thermal decomposition for nitromethane/nano-aluminum composites.

The thermal decomposition of pure nitromethane (NM) and NM/nano-aluminum (Al) composites was simulated by reactive molecular dynamics with ReaxFF-lg corrected force field parameters. The initial decomposition pathway of NM molecules in pure NM is C-N bond rupture. However, NM is decomposed early by the initial pathway of N-O bond rupture when it mixes with nano-Al because of the strong attraction of Al to O.

Thermal Decomposition Mechanism of 1,3,5,7-Tetranitro-1,3,5,7-tetrazocane Accelerated by Nano-Aluminum Hydride (AlH): ReaxFF-Lg Molecular Dynamics Simulation.

ReaxFF-low-gradient reactive force field with CHONAl parameters is used to simulate thermal decomposition of 1,3,5,7-tetranitro-1,3,5,7-tetrazocane (HMX) and AlH composite. Perfect AlH and surface-passivated AlH particles were constructed to mix with HMX. The simulation results indicate HMX is adsorbed on the surface of particles to form O-Al and N-Al bonds.

Abundance and morphology of charcoal in sediments provide no evidence of massive slash-and-burn agriculture during the Neolithic Kuahuqiao culture, China.

It remains debatable whether slash-and-burn practices were adopted in rice cultivation by the Neolithic Kuahuqiao culture in the Ningshao Plain, one of the birthplaces of rice farming. Here, we established charcoal-based indices to reconstruct the history of fire and vegetation in the Ningshao Plain since the last glacial period. We collected representative modern vegetation and conducted combustion and fragmentation experiments to simulate fire and depositional processes, respectively.

Crystal morphology prediction of 2,2',4,4',6,6'-hexanitrostilbene (HNS) by molecular scale simulation.

The spiral growth model was applied to predict the crystal morphology of 2,2',4,4',6,6'-hexanitrostilbene (HNS). We selected solvents of N,N-dimethylformamide (DMF), N-methyl pyrrolidone (NMP), and nitric acid (NA) to control the crystal morphologies of HNS. Molecular dynamic simulations were used to relax the constructed interface model.

Crystal Morphology Prediction and Anisotropic Evolution of 1,1-Diamino-2,2-dinitroethylene (FOX-7) by Temperature Tuning.

Temperature-induced morphological changes are one of the strategies for designing crystal shapes, but the role of temperature in enhancing or inhibiting crystal growth is not well understood yet. To meet the requirements of high density and low sensitivity, we need to control the crystal morphology of the energetic materials. We studied the crystal morphology of 1,1-diamino-2,2-dinitroethylene (FOX-7) in dimethyl sulfoxide/water mixed solvent by using the modified Hartman-Perdok theorem.

Reactive molecular dynamics simulation of the high-temperature pyrolysis of 2,2',2'',4,4',4'',6,6',6''-nonanitro-1,1':3',1''-terphenyl (NONA).

2,2',2'',4,4',4'',6,6',6''-Nonanitro-1,1':3',1''-terphenyl (NONA) is currently recognized as an excellent heat-resistant explosive. To improve the atomistic understanding of the thermal decomposition paths of NONA, we performed a series of reactive force field (ReaxFF) molecular dynamics simulations under extreme conditions of temperature and pressure. The results show that two distinct initial decomposition mechanisms are the homolytic cleavage of the C-NO bond and nitro-nitrite (NO → ONO) isomerization followed by NO fission.

Molecular dynamics simulation on the reaction of nano-aluminum with water: size and passivation effects.

The reaction of aluminum and water is widely used in the field of propulsion and hydrogen production, but its reaction characteristics at the nanometer scale have not been fully studied. In this paper, the effect of particle size and surface passivation of aluminum particle on the reaction mechanism was studied by using reactive molecular dynamics (RMD) simulation. The reduction of aluminum particle size can accelerate the reaction rate in the medium term (20-80 ps) due to the increase of activity, but it also produces an agglomeration effect as the temperature increases.

Molecular Modeling on Morphology of 3,4-Bis(3-nitrofurazan-4-yl)furoxan Crystals in Dichloroethane or Benzene Mixture Solvents.

According to the experiments, DNTF crystallizes in benzene/methylbenzene (1:1), benzene/methylbenzene/ethanol (2:3:5), and sym-dichloroethane solvents into two similar crystal shapes, namely strip and tetrahedral. There is a possibility that solvent changes the crystal morphology. In order to explain this phenomenon, the DNTF growth interface model was constructed according to the actual solution environment.

Uncovering the action of ethanol controlled crystallization of 3,4-bis(3-nitrofurazan-4-yl)furoxan crystal: A molecular dynamics study.

A computational strategy in consideration of attachment energy, temperature, solubility and supersaturation unravels details of the solvent effect on the crystal morphology. The crystal morphologies were predicted by the advanced screw dislocation growth model. This research sheds much light on the crystal growth mechanisms with the example of 3,4-bis(3-nitrofurazan-4-yl)furoxan (DNTF) in ethanol.

Reactive molecular dynamics simulation of thermal decomposition for nano-aluminized explosives.

Aluminized explosives have important applications in civil construction and military armaments, but their thermal decomposition mechanisms are not well characterized. Here, the thermal decomposition of TNT, RDX, HMX and CL-20 on Al nanoparticles is examined by reactive dynamics simulations using a newly parameterized reactive force field with low gradient correction (ReaxFF-lg). Partially passivated Al nanoparticles were constructed and mixed with TNT, RDX, HMX and CL-20 crystals and then the mixed systems are heated to a high temperature in which the explosives are fully decomposed.

Theoretical design of novel energetic salts derived from bicyclo-HMX.

We designed three novel cage energetic anions by introducing ionic bridges containing NΘ, N(OΘ) and N(NΘNO) into cis-2,4,6,8-tetranitro-1H,5H-2,4,6,8- tetraazabicyclo[3.3.0] octane (bicyclo-HMX or BCMHX).

Molecular dynamic simulation for thermal decomposition of RDX with nano-AlH particles.

Molecular dynamic simulation of a high explosive, RDX, mixed with AlH3 nanoparticles was performed by a newly parameterized ReaxFF force field. Testing of the ReaxFF shows that the mean absolute errors of the densities and bond lengths between calculated and experimental values are less than 7% and 3%, respectively. Using the ReaxFF, effects of AlH3 nanoparticles with different radii on the thermal decomposition of RDX were revealed.

Access to novel graphene-like sheet of hydroboron: first-principles investigation.

We designed a cyclic borane (B6 H12 ) molecule with a benzene-like structure, in which the six B atoms are located in the same plane. Three methods of B3LYP, MP2, and CCSD with the 6-311++G** basis were used to investigate its structure, electronic property, and stability. Next, we calculated the stability and electronic property of three hydroboron derivatives with fused rings of B10 H18 , B14 H24 , and B16 H26 .

Theoretical study of the geometries and decomposition energies of CO₂ on Al₁₂X: doping effect of Al₁₂X.

The adsorption and decomposition of CO₂ molecule on X-centered icosahedronal Al₁₂X clusters (doping atom X=Al, Be, Zn, Fe, Ni, Cu, B, C, Si, P) were investigated by the DFT methods of PW91 and PWC. Adsorption energies, chemisorption energies and energy barriers of physic- and chemisorptions for CO₂ were determined. It was found that the doping atoms and spin states have important influences on the Al₁₂X geometries, electronic properties and energies of the adsorption processes.

A DFT study of adsorption and decomposition of hexahydro-1,3,5-trinitro-1,3,5-triazine on Mg(0001) surface.

The adsorption and decomposition of hexogen (RDX) molecule on the Mg(0001) surface were investigated by the generalized gradient approximation (GGA) of density functional theory (DFT). The calculations employed a supercell (4 × 4 × 4) slab model and three-dimensional periodic boundary conditions. The strong attractive forces between RDX molecule and magnesium atoms induce the RDX's N - O bond breaking.

Adsorption and decomposition mechanism of hexogen (RDX) on Al(111) surface by periodic DFT calculations.

The adsorption of hexogen (RDX) molecule on the Al(111) surface was investigated by the generalized gradient approximation (GGA) of density functional theory (DFT). The calculations employ a supercell (4×4×3) slab model and three-dimensional periodic boundary conditions. The strong attractive forces between RDX molecule and aluminum atoms induce the N-O and N-N bond breaking of the RDX.