A new approach for characterizing paramagnetic sites in materials is introduced. It combines broadband fast magic-angle spinning (MAS) NMR data with ab initio computed paramagnetic NMR shifts using correlated wave functions. This study presents a challenging example of this. With Fe coordinated in a model compound, the PCN-224 porphyrin metal–organic framework (Fe@PCN-224 MOF) was used to elucidate the coordination geometry and electronic structure using ¹H and ¹³C MAS NMR spectra of the ligand atoms. The computationally predicted ¹³C NMR shifts on the paramagnetic Fe@PCN-224 MOF compared unprecedentedly well with experimental ¹³C NMR shifts and equally well for the diamagnetic counterpart, the Fe-free PCN-224 MOF. This is despite the 25 times wider NMR shift range of 1200 ppm for the paramagnetic Fe@PCN-224 MOF. We conclude that this approach is applicable to crystalline, noncrystalline, and molecular systems.

Efficient degradation of per- and polyfluoroalkyl substances (PFAS) remains a significant challenge due to its recalcitrant nature. In this study, a bismuth (Bi)/titanium (Ti) bimetallic coordination photocatalyst, featuring metal cation centers bridged by ligands, was synthesized. The incorporation of Bi and Ti resulted in coordinatively unsaturated metal sites that facilitate strong interactions with perfluorooctanoic acid (PFOA) via Ti−O and Bi−F complexation. The resulting electron redistribution towards the C−F bonds of PFOA facilitated bond weakening, thereby enabling the bimetallic coordination photocatalyst to effectively activate PFOA for degradation under UV₂₅₄ irradiation. Even an ultralow dosage (5 mg L⁻¹) resulted in complete PFOA degradation and 56.8 % defluorination within 5 h. Analysis of PFOA degradation intermediates identified short chain perfluorocarboxylic acids as the primary products. This study explores an ultralow-dosage, high-efficiency photocatalytic strategy based on Ti/Bi bimetallic coordination polymers, enabling effective PFOA degradation and defluorination by exploiting unsaturated metal sites on the catalyst surface. In addition to its practical implications for water purification, this approach elucidates the mechanistic insights into C−F bond activation and underscores a generalizable design strategy for developing catalysts targeting persistent organic pollutants.

The crystalline sponge (CS) method utilizes a crystalline porous material to arrange target molecules within its periodic pores. This enables the determination of the 3D atomic structures of organic molecules without the need for crystallization. However, its applicability is currently limited by the availability of suitable porous single crystals that can grow to a sufficient size for X-ray diffraction analysis. Although three-dimensional electron diffraction (3D ED) allows structure determination from nanosized crystals, ab initio structural analysis of organic molecules hosted in nanocrystalline sponges remains challenging and largely manual. Here, we present a 3D ED-based nanocrystalline sponge (NanoCS) workflow that integrates guest soaking, low-dose cryogenic data collection, and automated structure solution and refinement. A key advance is a newly developed automated approach for guest identification and structural analysis implemented in the AutoSolveX pipeline. Using the nanocrystalline bismuth-based metal–organic framework (MOF) SU-100 as a prototype crystalline sponge, we demonstrated the general applicability of this NanoCS strategy. 10 organic molecules, introduced as pure liquids, solutions, or vapors, are investigated. For all systems, 3D ED data collected under low electron fluence and cryogenic conditions enabled fully automated identification and refinement of the guest molecules using AutoSolveX. The results confirm the periodic arrangement of the guest molecules within the pores of SU-100, mediated by coordination bonding, hydrogen bonding, offset π–π stacking, and van der Waals interactions. This work establishes NanoCS combined with automated structural analysis as a practical and high-throughput platform for routine ab initio structural determination of organic molecules from nanocrystalline hosts.

Hexakis(4-(4-carboxylphenyl)phenyl)benzene, H₆cbb, was used to prepare the rod-based metal–organic frameworks (rod-MOFs) [Mn₄(cbb)(dmf)₂(OAc)₂] CTH-50 and [Gd₃(cbb)(dmf)₂(H₂O)(OAc)₃] CTH-51 by solvothermal synthesis (dmf = N,N-dimethylformamide) with single crystal diffraction revealing that CTH-50 (by X-ray) and CTH-51 (by electron diffraction) can be described as 5- and 6-connected yav-nets. Gas sorption analysis gave a BET surface area of 787 m²/g for CTH-50 and 187 m²/g for CTH-51, with CTH-50 having an Ideal Adsorbed Solution Theory (IAST) selectivity for SF₆ of 35 at 10 kPa, and thermogravimetry indicated the possible stability of CTH-50 to 300 °C and CTH-51 to 400 °C.

The fascinating feature of metal–organic frameworks is that they can respond to external stimuli, unlike other inorganic materials. This feature corresponds to the framework’s flexibility, which originates with the long-range crystalline order of the framework accompanied by cooperative structural transformability. We have synthesized a novel metal–organic framework comprised of Cu(I) nodes with pyrazine linkers and benzene-1,3,5-tricarboxylate acting as template anions, named CUCAM-1 [Cu(Py)₂(BTC)]_n. In the presence of polar solvent systems, CUCAM-1 undergoes an irreversible structural transformation to yield a mixed phase that consists of HKUST-1 [Cu₃(BTC)₂(H₂O)₃]_n and another CUCAM-2 [Cu(Py)(BTC)]_n MOFs, whose novel structure is successfully revealed by continuous rotation electron diffraction from the mixture. In this structural transformation, a new ligand exchange occurs where template anions become ligands, confirmed by single crystal X-ray analysis. Further, structural transformation and the mechanism are explained by ab initio molecular dynamics (AIMD) simulations. Interestingly, different halides (F^–, Cl^–, and Br^–) can be accompanied to affect/control the composition of the second phase by favoring the formation of the HKUST-1 phase over CUCAM-2, which was evident by the powder X-ray diffraction studies. Furthermore, the structural transformation induced by I^– resulted in a colorimetric response due to the formation of a new MOF CUCAM-3, paving the way for use as an iodide detector.

We present the successful synthesis and characterization of a one-dimensional high-entropy oxide (1D-HEO) exhibiting nanoribbon morphology. These 1D-HEO nanoribbons exhibit high structural stability at elevated temperatures (to 1000°C), elevated pressures (to 12 gigapascals), and long exposure to harsh acid or base chemical environments. Moreover, they exhibit notable mechanical properties, with an excellent modulus of resilience reaching 40 megajoules per cubic meter. High-pressure experiments reveal an intriguing transformation of the 1D-HEO nanoribbons from orthorhombic to cubic structures at 15 gigapascals followed by the formation of fully amorphous HEOs above 30 gigapascals, which are recoverable to ambient conditions. These transformations introduce additional entropy (structural disorder) besides configurational entropy. This finding offers a way to create low-dimensional, resilient, and high-entropy materials.

High Entropy Alloys (HEAs) have garnered attention due to their remarkable tribological attributes. Predominantly, failure mechanisms in HEAs emanate from stress-induced dislocations, culminating in crack propagation and film delamination. In this study, we report on the synthesis of 2D HEA of (MoWNbTaV)0.2S2 which facilitates shear-induced energy dissipation at sliding interfaces. The ball-on-disk tribological investigations demonstrate unprecedentedly low average coefficients of friction (0.076) and wear rates (10−9 mm3 (N∙m)−1) under high contact pressures (0.936 GPa) within ambient conditions. Employing multi-scale characterizations alongside molecular dynamic simulations, we elucidate that the presence of the HEA triggers tribocatalytic activity under high contact pressures emerging as a pivotal factor in extending lubricant lifespan during tribological tests. The resilient lubriciousness coupled with the facile spray coating methodology of (MoWNbTaV)0.2S2 in ambient environments paves the way for the development of a new class of solid lubricants based on 2D HEA.

We present serial electron diffraction with tilt (t-SerialED), a method for fast autonomous phase and structural analysis of beam-sensitive, nano-sized polycrystalline materials. Unlike traditional workflows collecting datasets crystal by crystal, t-SerialED acquires datasets using a batch-by-batch approach, which speeds up the data acquisition. t-SerialED combines robust indexing from 3D reciprocal space with still-shot integration and merging methods from serial crystallography. t-SerialED enables high-throughput analysis of beam-sensitive, multi-phase mixtures across a wide range of materials, from nanoporous frameworks to pharmaceutical compounds. By resolving key challenges in serial crystallography such as indexing and preferred orientation, this method enables precise structure determination, including the visualization of guest molecules and non-covalent interactions like hydrogen bonding and proton charge transfer. Demonstrated on a range of samples from nanoporous materials to pharmaceuticals, t-SerialED expands the capabilities of serial chemical crystallography from single-phase to complex multi-phase systems. It can become a complementary method to traditional crystallography methods, offering a robust solution for routine quantitative phase analysis and structure determination.

Engineering the building blocks in metal–organic materials is an effective strategy for tuning their dynamical properties and can affect their response to external guest molecules. Tailoring the interaction and diffusion of molecules into these structures is highly important, particularly for applications related to gas separation. Herein, we report a vanadium-based hybrid ultramicroporous material, VOFFIVE-1-Ni, with temperature-dependent dynamical properties and a strong affinity to effectively capture and separate carbon dioxide (CO₂) from methane (CH₄). VOFFIVE-1-Ni exhibits a CO₂ uptake of 12.08 wt % (2.75 mmol g^–1), a negligible CH₄ uptake at 293 K (0.5 bar), and an excellent CO₂-over-CH₄ uptake ratio of 2280, far exceeding that of similar materials. The material also exhibits a favorable CO₂ enthalpy of adsorption below −50 kJ mol^–1, as well as fast CO₂ adsorption rates (90% uptake reached within 20 s) that render the hydrolytically stable VOFFIVE-1-Ni a promising sorbent for applications such as biogas upgrading.

Oxygen reduction reaction (ORR) is of critical significance in the advancement of fuel cells and zinc-air batteries. The iron-nitrogen (Fe−N_x) sites exhibited exceptional reactivity towards ORR. However, the task of designing and controlling the local structure of Fe species for high ORR activity and stability remains a challenge. Herein, we have achieved successful immobilization of Fe species onto the highly curved surface of S, N co-doped carbonaceous nanosprings (denoted as FeNS/Fe₃C@CNS). The induction of this twisted configuration within FeNS/Fe₃C@CNS arose from the assembly of chiral templates. For electrocatalytic ORR tests, FeNS/Fe₃C@CNS exhibits a half-wave potential (E_1/2) of 0.91 V in alkaline medium and a E_1/2 of 0.78 V in acidic medium. The Fe single atoms and Fe₃C nanoparticles are coexistent and play as active centers within FeNS/Fe₃C@CNS. The highly curved surface, coupled with S substitution in the coordination layer, served to reduce the energy barrier for ORR, thereby enhancing the intrinsic catalytic activity of the Fe single-atom sites. We also assembled a wearable flexible Zn-air battery using FeNS/Fe₃C@CNS as electrocatalysts. This work provides new insights into the construction of highly curved surfaces within carbon materials, offering high electrocatalytic efficacy and remarkable performance for flexible energy conversion devices.