CrystEngComm最新文献

We accelerate a key step in crystal structure prediction (CSP) using machine learning and report its robustness on a wide array of pharmaceutical molecules. The speedup achieved by our scheme allows for a scale-up in both the number of candidate drug molecules studied and the level of theory employed in their treatment, paving the way for tackling more complex crystal energy landscapes.

The substitution of noble metals with cost-effective copper nanoparticles (Cu NPs) in the preparation of metal/semiconductor composite catalysts holds significant environmental and economic implications for the degradation of various organic pollutants. However, the development of highly active and stable Cu NPs catalysts has emerged as a key challenge in the progression of non-noble metal catalysts. In this study, the reducibility of glutathione (GSH) was employed to reduce Cu²⁺ to Cu NPs, resulting in the formation of stable Cu-GSH nanoparticles through S–H bonds. An electrostatic self-assembly strategy was used to load Cu-GSH onto WO₃ nanorods, thereby designing a Cu GSH/WO₃ catalytic material with highly efficient charge transport efficiency. Under visible light irradiation, 3 wt% Cu GSH/WO₃ demonstrated excellent degradation performance for organic pollutants, achieving the degradation of 99.8% of Rh B and 98.6% of TC within 60 minutes. Experimental results from photoelectrochemical (PEC) and electron spin resonance (ESR) analyses indicated that Cu GSH functions as an efficient electron trap, which triggers electron flow driven by the Schottky barrier, capturing the photoexcited electrons from WO₃. This greatly enhances the separation efficiency of WO₃ carriers and extends the lifetime of the carriers. It is hoped that this work will provide a viable approach for the synthesis of new high-efficiency composite photocatalytic materials.

High-quality transparent cubic lutecia-stabilized zirconia (LSZ) and LSZ:Yb_0.25Tm_0.5Ho_0.03 single crystals were fabricated by the OFZ (optical floating zone) method for the first time. For comparison, YSZ and YSZ:Yb_0.25Tm_0.5Ho_0.03 single crystals were also fabricated. The transmittance of the LSZ single crystal (80.7%) is slightly lower than that of the YSZ single crystal (86.3%) in the visible light region, which is attributed to the LSZ single crystal with a higher density (6.604 g cm⁻³) in comparison with that of the YSZ single crystal (5.973 g cm⁻³). No absorption peaks were observed in the transmission and absorption spectra of LSZ and YSZ within 200–1100 nm, indicating that both crystals are excellent host crystals. The density of LSZ:Yb_0.25Tm_0.5Ho_0.03 single crystals (6.596 g cm⁻³) is also higher than that of YSZ:Yb_0.25Tm_0.5Ho_0.03 single crystals (6.005 g cm⁻³). The absorption spectra of LSZ:Yb_0.25Tm_0.5Ho_0.03 and YSZ:Yb_0.25Tm_0.5Ho_0.03 single crystals exhibited several absorption peaks at 363, 453, 678, and 785 nm and a strong broad absorption band within 850–1000 nm. The upconversion photoluminescence (UCPL) spectrum of the LSZ:Yb_0.25Tm_0.5Ho_0.03 single crystal excited at 980 nm exhibited several emission peaks at 308, 373, 488, 540, 550, 655 and 794 nm; similar emission peaks were observed in the UCPL spectrum of the YSZ:Yb_0.25Tm_0.5Ho_0.03 single crystal. The intensities of the emission peaks of the former are higher than those of the corresponding peaks of the latter, which is due to the former having a higher density and lower phonon energy in comparison with the latter. Power curves indicated that the 308 and 373 nm emissions are 4-photon upconversion processes, the 488 nm emission is a 3-photon process, and the 540 nm and 655 nm emissions are 2-photon processes. These results indicate that under the excitation at 980 nm, the LSZ:Yb_0.25Tm_0.5Ho_0.03 single crystal has high efficiency over the YSZ:Yb_0.25Tm_0.5Ho_0.03 single crystal in ultraviolet and visible light emissions.

Constructing multifunctional films using layered rare earth (RE) hydroxide (LRH) nanosheets as building blocks is a popular topic. The traditional synthesis of LRH films involves four main steps: bulk crystal synthesis, intercalation of long-chain organic anions, exfoliation, and layer-by-layer self-assembly into a film. In this work, the layered gadolinium hydroxide (LGdH) film was directly synthesized via electrodeposition within 10 minutes. The effects of the synthesis conditions, including working voltage, concentration of nitrate solution, and the reaction temperature, on the structural characteristics and morphologies were investigated. In order to improve the photoluminescence performance of LGdH:RE films, the quenching groups in the LGdH structure were removed/replaced via appropriate heat treatment/anion exchange with MoO₄²⁻, based on the thermal behaviour/anion exchange properties of the LGdH, and Gd₂O₃:RE/NaGd(MoO₄)₂:RE films with enhanced photoluminescence and stability were obtained. The electrodeposition combined with heat treatment/anion exchange techniques established in this study led to the rapid synthesis of Gd₂O₃:RE/NaGd(MoO₄)₂:RE films, and could have wide implications for the generation of other types of inorganic functional films.

Herein, cobalt is incorporated into a polyoxotungstate (POW) to obtain a new organic–inorganic hybrid Co-containing POW with a reliable 1D nanowire structure. The Co-containing POW exhibits superior oxygen evolution reaction (OER) activity in a neutral medium compared with its isomorphic Zn-containing POW, highlighting the critical role of cobalt in enhancing OER performance. This work provides a new insight into the structure–property relationship of metal oxides in electrocatalysis.

A post-synthetic modification was employed to incorporate lanthanide Eu³⁺ ions into carbazole-functionalized UiO-67 metal–organic frameworks, successfully fabricating an efficient dual-emission fluorescence probe. The Eu³⁺-doped composite manifests superior luminescent properties and remarkable fluorescence stability, attributable to the sensitization and reinforcement afforded by the parent framework. Notably, the ligand's capability to capture external light and sensitize Eu³⁺ emissions led to observing characteristic peaks at 435 nm for the intrinsic ligand and 591, 614, 651, and 701 nm for Eu³⁺. The introduction of dipicolinic acid (DPA) serves a dual role: it acts as an antenna to absorb photons and replaces the coordinated water molecules of Eu³⁺, thereby preventing fluorescence quenching by water's O–H vibrations. Additionally, establishing hydrogen bonding between DPA and the carbazole dicarboxylic acid (CDC) initiates an intermolecular charge transfer (ICT) process, enhancing the ligand's fluorescence. Besides, the addition of DPA concurrently enhances the fluorescence emissions of both the ligand and Eu³⁺, displaying an unusual dual-enhanced “turn-on” fluorescence mode with an impressively low detection limit of 0.538 μM, accompanied by discernible color changes visible to the naked eye. Utilizing Eu@UiO-67-CDC as a test paper facilitates rapid on-site detection of DPA, eliminating the need for complex instrumentation. Moreover, the Eu@UiO-67-CDC probe can quantify DPA in environmental matrices such as river and lake water, with better recovery rates, indicating its significant potential for practical applications.

A novel photocatalyst for the construction of tubular graphitic carbon nitride (g-C₃N₄)/nickel oxide (NiO) heterojunction on carbon cloth (CC) is reported. Using ZnO nanorods as sacrificial template, tubular g-C₃N₄ nanosheets with thickness of 20 nm were grown on carbon cloth by thermal condensation. Then, NiO nanosheets were grown on g-C₃N₄ tubes by electrodeposition and calcination. In the light of visible light, the removal rates of rhodamine B (RhB) by g-C₃N₄/NiO/CC and g-C₃N₄/CC photocatalysts were 98% and 32%, respectively, within 60 min. The experiment was repeated five times, we found no significant decrease in photocatalyst activity. CC supported photocatalysts have broad application prospects in the degradation of organic dyes.

Expression of concern for ‘Designing novel morphologies of L-cysteine surface capped 2D covellite (CuS) nanoplates to study the effect of CuS morphologies on dye degradation rate under visible light’ by Shahid Iqbal et al., CrystEngComm, 2020, 22, 4162–4173, https://doi.org/10.1039/D0CE00421A.

Coordination compounds with slow magnetic relaxation are of great interest due to their magnetic bistability. Herein, three cobalt(II) coordination polymers, formulated as {[Co₂(btca)(bpym)]·4H₂O}_n (1) and {[Co₂(btca)(bpym)]·2DMF·2H₂O}_n (2), {[Co₂(H₂btca)₂(bpym)]}_n (3) (H₄btca = 1,2,4,5-benzenetetracarboxylic acid; bpym = 2,2′-bipyrimidine), were solvothermally synthesized and magnetically characterized. Single-crystal structural analyses reveal that compounds 1 and 2 are Co²⁺ dimer-based one-dimensional (1D) and 2D coordination polymers, respectively, while compound 3 is a Co²⁺ chain-based 2D coordination polymer with a new topology. The Co²⁺ dimers and chains in these compounds are well magnetically isolated due to the bulk tetracarboxylic linker. Magnetic studies reveal that antiferromagnetic interactions exist between the Co²⁺ ions bridged by the bpym ligand. For 1, no relaxation behavior can be detected, suggesting the paramagnetic behavior of 1. Interestingly, alternating current (AC) magnetic measurements observed slow magnetic relaxation under a 1000 Oe field for 2 and 3. These results provide not only three cobalt(II) coordination polymers with varying topology and magnetic behaviors but also a pyrimidine–tetracarboxylic ligand platform for designing new slow magnetic relaxing coordination polymers.

The synthesis, structures, adsorption, and magnetic properties of two two-dimensional (2D) coordination polymers, [M(btca)_1/2(bpe)_1/2(H₂O)₂]_n (M = Ni²⁺ (1) and Co²⁺ (2); H₄btca = 1,2,4,5-benzenetetracarboxylic acid; bpe = 1,2-di(4-pyridyl)ethane) constructed by mixed bipyridyl–tetracarboxylate ligands were reported. Single-crystal X-ray diffraction studies reveal the 3D hydrogen-bonded networks sustained by O–H⋯O H bonds between the 2D layers. The 2D structure topology of the compounds is a new {4.6·2}2{4·2.6·2.8·2} bex topology while the 3D framework is different because of the distinct H bond interactions. Both compounds exhibit high thermal stability above 150 °C. N₂ adsorption measurements reveal that both compounds are non-porous structures, while compound 1 exhibits CO₂ adsorption, possibly due to structural expansion after CO₂ accommodation. Magnetic investigations indicated that framework 2 exhibits field-induced slow magnetic relaxation due to the large magnetic anisotropy of Co²⁺ ions (zero-field splitting parameter D = 42.1 cm⁻¹), while framework 1 shows simple paramagnetism with a small D of −11.3 cm⁻¹. This work not only provides two new coordination polymers but also a potential bipyridyl–tetracarboxylate approach for the design and construction of single-ion magnet (SIM) frameworks.