Yajie Wang

Single-metal-atom chains (SMACs) represent the ultimate limit of one-dimensional nanostructures. They serve as archetypal model systems for condensed matter physics and constitute fundamental building blocks for next-generation nanoelectronics. However, synthesis of SMACs suitable for practical applications remains challenging. In this work, we create micrometer-long, carbon-sheathed copper SMACs at milligram scale by compressing β-copper phthalocyanine to above 21 gigapascals. The SMACs are in atom-scale ordering, are isolable through acid-assisted exfoliation, and exhibit exceptional stability, with Cu-Cu distance confined at 2.57 angstroms. Anisotropic conductance and antiferromagnetic interactions are suggested by experimental and computational results. This work establishes a universal synthetic strategy for sheathed SMACs, positioning them as a compelling platform for prospective electronic and spintronic applications.

Nonbenzenoid graphene nanoribbons such as biphenylene networks have gained increasing attention owing to their promising electronic and transport properties, but their scalable synthesis is still a huge challenge. Pressure-induced topochemical polymerization is an effective method to assemble molecular units into extended carbon materials, and the structure and properties of the carbon material can be tuned by modifying its molecular precursors. Herein, by directly compressing biphenylene at room temperature, we successfully synthesized crystalline biphenylene nanoribbons in milligram scale. By combining the spectroscopy and single crystal X-ray diffraction methods as well as theoretical calculation, we found that biphenylene experiences a minor phase transition above 3 GPa, and two phenyls in biphenylene undergo sequential para-polymerization along the a-axis to form a ribbon structure at 14 GPa. Our work provides an important reference for the high-pressure reaction of aromatics and the synthesis of complex nanoribbons.

Pressure-induced polymerization (PIP) of aromatic molecules has emerged as an effective method for synthesizing various carbon-based materials. The selection of suitable functionalized molecular precursors is crucial for obtaining the desired structures and functions. In this work, 1,4-difluorobenzene (1,4-DFB) was selected as the building block for PIP. In situ high-pressure investigations of 1,4-DFB reveal a phase transition at approximately 12.0 GPa and an irreversible chemical reaction at 18.7 GPa. Structural analysis of the product and the kinetics of the reaction uncovered the formation of pseudo-hexagonal stacked fluoro-diamond nanothreads with linear growth. Compared to the crystal structure of benzene under high pressure, 1,4-DFB exhibits higher compression along the [001] axis. The anisotropic compression is attributed to the stronger H⋯π interactions along the [01] axis and the potential compression-inhibiting H⋯F interactions along the [100] and [010] axes, and it facilitates a possible reaction pathway along the [01] axis. This work emphasizes the crucial role of functionalization in modulating molecular stacking and influencing the reaction pathway.

Our work studied the structural changes of Gd@C ₈₂ under high pressure and successfully synthesized Gd-doped diamond which has the paramagnetic properties using Gd@C ₈₂ precursors under high pressure and high temperature.

Predicting the distribution of fractured and dissolved reservoirs in granitic buried hills is a prerequisite for finding high-quality hydrocarbon reservoirs and improving the success rate of exploration activities. Granitic buried-hill reservoirs in the Bongor Basin are characterized by strong heterogeneity and poor lateral continuity. Through the analysis of seismic, core, logging and dynamic production data, this study predicts the distribution of fractured reservoirs and fractured-cave reservoirs in the granitic buried hills in the BC Block of the Bongor Basin. In this study, we predict fractured reservoirs using coherence cubes and linearly enhanced attributes and identify fractured-cave reservoirs with single-frequency attribute bodies. Integrated predictions of fractured reservoirs and fractured-cave reservoirs are conducted using attribute fusion techniques. With these methods, good results have been achieved in reservoir prediction in BC buried hills. Furthermore, this study summarizes a set of granitic buried-hill reservoir prediction techniques for densely inverted rift basins in the Central African Rift System.

Under pressure of 1–100 GPa, unsaturated organic molecules tend to form covalent bond to each other for a negative enthalpy change, which often produces polymeric materials with extended carbon skeleton. The polymerization reactions typically happen in crystal, which promotes the topochemical process. This review summarized the topochemical polymerization processes of several alkynes, aromatics, and alkynylphenyl compounds, including the critical crystal structures before the reaction, bonding process, and the structure of the products. Secondly, this review also summarized the condensation reaction identified in the polymerization process, including the elimination of small molecules such as NH₃, etc.

The pressure-induced phase transition and polymerization of nitrogen-rich molecules are widely focused on due to their extreme importance for the development of green high-energy-density materials. Here, we present a study of the phase-transition behaviour and chemical reaction of 1H-tetrazole up to 100 GPa using in situ Raman, IR, X-ray diffraction, neutron diffraction techniques and theoretical calculations. A phase transition above 2.6 GPa was identified and the high-pressure structure was determined with one molecule in a unit cell instead of two molecules as reported before. The 1H-tetrazole polymerized reversibly below 100 GPa, probably through carbon–nitrogen bonding instead of nitrogen–nitrogen bonding. Our studies update the structure model of the high-pressure phase of 1H-tetrazole, and present the possible intermolecular bonding route for the first time, which gives new insights to understand the phase transition and chemical reaction of nitrogen-rich compounds, and is of benefit for designing new high-energy-density materials.

Octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) is one of the most important energetic materials. Investigations on its phase transitions and chemical reactions under extreme conditions are very important to understand the explosion process and design new energetic materials. By using a diamond anvil cell combined with in situ Raman, IR and X-ray diffraction techniques up to a pressure of ∼40 GPa, we found that β-HMX undergoes four reversible phase transitions without any chemical reaction under external pressure at room temperature. Isostructural phase transitions emerge around 5 GPa (ζ-HMX) and 10–13 GPa (ε-HMX), and another two phases emerge at 16 GPa (η-HMX) and 27 GPa (ϕ-HMX). The unit cells of ζ-HMX and ε-HMX were determined as a = 6.215 Å, b = 10.417 Å, c = 8.272 Å, β = 124.88°, P2₁/c at 6.2 GPa and a = 6.130 Å, b = 9.846 Å, c = 8.258 Å, β = 125.06°, P2₁/c at 12.6 GPa, respectively. The crystal structures of β, ζ, and ε-HMX were obtained by Rietveld refinement, based on which the rotations of NO₂ groups were found to be related to the phase transition at 5 GPa. Additionally, HMX decomposes at 8.7 GPa and 300 °C. Carbon dioxide, hydroxyl, imino and hydroxyimino groups were detected in the IR spectrum, which indicates that the reaction contains a hydrogen transfer process. Our investigation uncovers the structural variation of β-HMX under external pressure and identifies the decomposition products under extreme conditions, which provides new insight to understand the detonation process of energetic materials.

Pressure‐induced polymerization (PIP) of aromatics is a novel method for constructing sp³‐carbon frameworks, and nanothreads with diamond‐like structures were synthesized by compressing benzene and its derivatives. Here by compressing a benzene‐hexafluorobenzene cocrystal (CHCF), H‐F‐substituted graphane with a layered structure in the PIP product was identified. Based on the crystal structure determined from the in situ neutron diffraction and the intermediate products identified by gas chromatography‐mass spectrum, we found that at 20 GPa CHCF forms tilted columns with benzene and hexafluorobenzene stacked alternatively, and leads to a [4+2] polymer, which then transforms to short‐range ordered H‐F‐substituted graphane. The reaction process involves [4+2] Diels–Alder, retro‐Diels–Alder, and 1‐1′ coupling reactions, and the former is the key reaction in the PIP. These studies confirm the elemental reactions of PIP of CHCF for the first time, and provide insight into the PIP of aromatics.