结构化学最新文献

The identical molecular size and similar physical properties of carbon dioxide (CO₂) and acetylene (C₂H₂) make their adsorptive separation extremely challenging to achieve with most adsorbents. Reports on the separation of CO₂ and C₂H₂ mixtures by zeolites are even rarer with the mechanism of adsorptive separation requiring further exploration. In this paper, we report that ion modulation of zeolite 5A promotes the difference in kinetic diffusion of CO₂ and C₂H₂, realizing the inverse separation of zeolite from selective adsorption of C₂H₂ to selective adsorption of CO₂. Creating a compact pore space restricting the orientation of gas molecules enables charge recognition. The positive electrostatic potential at the pore openings was utilized to hinder the diffusion of C₂H₂ between the cages while ensuring the transfer of CO₂, increasing their diffusion differences in pore channels and leading to the CO₂/C₂H₂ kinetic selectivity of 31.97. Grand canonical Monte Carlo (GCMC) simulation demonstrates that the CO₂ distribution in K-5A-β is significantly higher than that of C₂H₂. Dynamic breakthrough experiments verify the excellent performance of material in practical CO₂/C₂H₂ separation, for CO₂/C₂H₂ (50/50 and 1/99, V/V) mixtures can be separated in one step, thus directly generating high purity C₂H₂ (> 99.95%), which provides a promising thought for the zeolite-based separation of CO₂ and C₂H₂.

Thermo-responsive microcrystals exhibiting obvious emission intensity or color changes have great potentials in sensing, information encryption, and microelectronics. We report herein the binary assembly of a blue-emissive iridium complex and a red-emissive ruthenium complex into homogeneously-doped or optically-heterostructured microcrystals with thermo-responsive properties. Depending on the assembly conditions, lateral or longitudinal triblock heterostructures with a microplate shape are obtained, which display distinct emission pattern changes upon heating as a result of the decreased efficiency of energy transfer. In addition, branched heterostructures are prepared by a stepwise assembly. The luminescence polarization of the homogeneously-doped binary crystals and the waveguiding property of the longitudinal triblock heterostructure are further examined. This work evidences the versatility of transition metal complexes in the assembly into various luminescent nano/micro structures with potential applications in thermo-sensing and nanophotonics.

Interface is a necessary channel of carrier permeation in sulfide-based all-solid-state lithium battery (ASSLB). Homogeneous and fast lithium-ion (Li⁺) interfacial transport of cathode is the overriding premise for high capability of ASSLBs. However, the inherent transport heterogeneity of crystalline materials in cathode and the cathode active material (CAM)/sulfide solid electrolyte (SSE) interfacial issues result in high interfacial impedance, decreasing the Li⁺ transfer kinetics. In this review, we outline the Li⁺ transport properties of CAMs and SSEs, followed by a discussion of their interfacial electro-chemo-mechanical issues. Commentary is also provided on the solutions to the multiple-scale interfacial Li⁺ transport failure. Furthermore, the underlying interdependent mechanisms between electrodes are summarized and overviewed. Finally, we suggest future paths to better comprehend and promote the interfacial Li⁺ transport in ASSLBs. This review provides an in-depth understanding of cathodal interfacial issues and the proposed improvement strategies will provide guidance for further advancement of high-performance ASSLBs.

Zero-dimensional (0D) hybrid metal halides are considered as promising light-emitting materials due to their unique broadband emission from self-trapped excitons (STEs). Despite substantial progress in the development of these materials, the photoluminescence quantum yields (PLQY) of hybrid Sb–Br analogs have not fully realized the capabilities of these materials, necessitating a better fundamental understanding of the structure-property relationship. Here, we have achieved a pressure-induced emission in 0D (EATMP)SbBr₅ (EATMP = (2-aminoethyl)trimethylphosphanium) and the underlying mechanisms are investigated using in situ experimental characterization and first-principles calculations. The pressure-induced reduction in the overlap between the STE states and ground states (GSs) results in the suppression of phonon-assisted non-radiative decay. The photoluminescence (PL) evolution is systematically demonstrated to be controlled by the pressure-regulated exciton-phonon coupling, which can be quantified using Huang-Rhys factor S. Through detailed studies of the S-PLQY relation in a series of 0D hybrid antimony halides, we establish a quantitative structure-property relationship that regulating S value toward 21 leads to the optimized emission. This work not only sheds light on pressure-induced emission in 0D hybrid metal halides but also provides valuable insights into the design principles for enhancing the PLQY in this class of materials.

The sp² carbon-conjugated covalent organic frameworks (COFs) with fully π-conjugated lattice and high chemical stability are promising heterogeneous photocatalysts. Herein, we report the design and synthesis of a novel palladium (Pd) porphyrin-based sp² carbon-conjugated COF (PdPor-sp²c-COF) with an eclipsed AA stacking 2D structure. Interestingly, PdPor-sp²c-COF showed high crystallinity, good chemical stability, and a broad absorption of visible light. Moreover, compared to our previously reported metal-free Por-sp²c-COF, PdPor-sp²c-COF displays an improved photocatalytic performance in the selective aerobic oxidation of sulfides under green light irradiation. The systematic mechanistic studies testified that the enhanced photocatalytic activity can be ascribed to promoting energy transfer pathway over PdPor-sp²c-COF. Our study clearly demonstrates that it is favorable to promote the energy transfer pathway in sp² carbon-conjugated COFs by using metalloporphyrin-based molecular building blocks. This work will inspire us to design and synthesize novel photocatalysts based on COFs for the selective aerobic oxidation.