CrystEngComm最新文献

In this comprehensive review, we have introduced two distinct types of multinuclear zinc sulfide superpolyhedral molecular clusters and zinc sulfide quantum dots. Two distinct categories of hyper polyhedral zinc sulfide clusters are identified: Zn10, categorized under T3 symmetry, and Zn8, classified under P1 symmetry. Both Zn10 and Zn8 clusters feature not only μ₁-S and μ₂-S species, which are attached to ligands, but also μ₃-S and μ₄-S species that remain unattached to ligands. Furthermore, the zinc and sulfur atoms within these cluster molecules possess the versatility to be substituted by alternative cations or anions, leading to the formation of corresponding derivatives. By comparing synthetic methodologies, structural attributes, and potential applications of the multinuclear zinc sulfide superpolyhedral molecular clusters and zinc sulfide quantum dots, we have delved into the intricate relationship between zinc sulfide quantum dots and these two classes of zinc sulfide clusters, offering a fresh perspective. From a synthetic standpoint, the preparation of zinc sulfide quantum dots often shares similarities with the synthesis of Zn10 clusters, while some methods also mirror the synthesis of Zn8 clusters utilizing reactors. Quantum dots typically exhibit larger sizes compared to cluster molecules, and their growth is characterized by rapid and continuous expansion, accompanied by a continuous red-shift of the edge band peaks in their UV-vis absorption spectra. In contrast, cluster molecules display discrete and heterogeneous growth patterns, with abrupt transitions from one discrete size to another larger discrete size, mirrored by individual sharp peaks in their UV-vis absorption spectra. Regarding applications, both entities share similar domains of utilization, albeit with distinct underlying mechanisms. By elucidating these differences and similarities, we aim to foster further advancements in the field of zinc sulfide-based materials.

In this study, a crystalline material CuPMTT was synthesized via coordination self-assembly strategy. The surfaces of CuPMTT are densely populated with thiol groups that effectively capture Hg²⁺ ions, achieving an adsorption rate nearing 90% and a separation coefficient of 4.51 against Cu²⁺, thus outperforming conventional adsorbents and presenting a significant advancement in environmental protection chemistry.

Metal–organic frameworks (MOFs), self-assembled by metal ions and organic ligands, have been utilized as active layers in resistive random-access memory (RRAM) devices due to their tunable composition and structure advantages, high porosity, and diverse interactions between guest molecules and host frameworks. As one kind of special MOF, MOF nanosheets not only inherit the benefits of MOFs but also present unique two-dimensional nanoscale thicknesses. Their special properties make them beneficial for fabricating MOF films. Thus, they could be promising materials for RRAM devices. Herein, we synthesized two porphyrin MOF nanosheets and then fabricated MOF films by spin-coating. After that, we used the films for resistive switching (RS) layers in memory devices. The as-fabricated RRAM devices exhibit write-once-read-many-times memory characteristics and good nonvolatile stability. Furthermore, due to the unique luminescence of the porphyrin linker, we investigated the light-induced resistive switching characteristics. The result shows that these porphyrin-based MOF nanosheet films exhibited ternary memory properties. This RS modulation is likely related to the photoinduced electrons and holes forming along channels consisting of porphyrin molecules. This MOF-based light-mediated memory device can be a candidate for achieving environment-responsive devices and has applications in information storage devices.

To achieve high-performance optoelectronic devices and thermoelectric behaviour, non-stoichiometric compositions have been utilised in ternary transition metal dichalcogenides. This study marks the first report on the growth of Cu_xSb_1−xSe₂ (x = 0.2, 0.4, 0.6, 0.8) crystals using the Bridgman technique. We investigated the impact on their structural, optical, thermal and electrical properties in comparison with pure CuSbSe₂. Powder X-ray diffraction confirmed the presence of the dominant orthorhombic CuSbSe₂ phase along with minor secondary phases and this result was well supported by Raman spectroscopy. The crystallite size increases from 12 nm to 27 nm while the lattice strain decreases from 0.0116 to 0.0054 with Cu content in the crystal. Elemental analysis carried out by EDAX has reflected the desired stoichiometry of each crystal. FESEM images have shown flat as well as layer growth on their surfaces, thereby giving an indication that the growth of crystals occurred by a layer-by-layer growth mechanism. Raman spectra indicated the red shift in the A_g vibrational mode of CuSbSe₂ with increasing Cu proportion. The direct bandgap of each crystal is reduced from 1.55 eV to 1.42 eV with higher Cu percentage which is determined from the Kubelka–Munk function using the recorded reflectance spectrum which shows that these crystals can be promising candidates for optoelectronic applications. The positive value of the Seebeck coefficient (S) demonstrates the p-type semiconducting nature of each crystal measured in the temperature range of 323 K to 593 K. Among the grown crystals, P3 (Cu_0.6Sb_0.4Se₂) exhibited the superior power factor and ZT values of 0.0182 μW cm⁻¹ K⁻² and 0.935 × 10⁻⁴ at 595 K, respectively. The TGA of each crystal demonstrated single step decomposition, showcasing a maximum weight loss of 18.07% for the P4 crystal, which is confirmed by DTG. To assess the photodetection properties of each crystal, I–V curves and pulse photoresponses are recorded in parallel to plane configuration. Among all grown crystals, the P3 (Cu_0.6Sb_0.4Se₂) crystal based photodetector exhibits superior responsivity and detectivity of 0.014 mA W⁻¹ and 5.656 × 10⁸ Jones, respectively. These findings show that these crystals can be considered as a choice for thermoelectric as well as photodetection applications.

Cerium oxide-supported platinum nanoparticles are widely used in the CO-PROX reaction. Due to expense and rarity, developing synthetic routes that reduce the platinum load and improve the performance of catalysts is essential. A rod-shaped ceria was used as the support, and a series of PtCo_x/CeO₂-r catalysts with constant low Pt loading of 0.21 wt% were prepared by a co-impregnation method. Combined with the performance using different atomic ratios and characterizations, the catalysts presented strong interaction among Pt, Co and Ce at Co/Pt = 9 and showed the best catalytic performance, making a CO conversion increase of 18.0% at 80 °C but a decrease in the best conversion temperature of 90 °C to 80 °C, as compared with the Pt/CeO₂-r catalysts. The enhanced activity of PtCo₉/CeO₂-r was attributed to the synergistic effect of Pt–Co–Ce and reducing the Pt–O–Ce bond energy, which promoted the redox cycle via the Mars–van Krevelen mechanism. It is helpful in reducing the reaction temperature, widening the temperature window and improving the selectivity of CO₂. When the concentration of CO was 10 000 ppm, and the WHSV was 30 000 mL g⁻¹ h⁻¹, the optimal conversion of the catalyst could reach 96.6%, and the optimal conversion temperature was 80 °C.

In this study, a Pr/CDs/SSS/PbO₂ electrode with good electrocatalytic activity and superior stability was successfully prepared by an electrodeposition process. XRD results showed that the doping of the Pr element inhibited the PbO₂ crystal growth, resulting in the complete disappearance of the α-PbO₂ diffraction peaks. Compared with the pure PbO₂ electrode, the Pr/CDs/SSS/PbO₂ electrode possesses a smaller grain size and a more compact electrode surface structure. In addition, the results of XRD and XPS confirmed that Pr³⁺ and Pr⁴⁺ existed simultaneously in the electrode, which increased the oxygen precipitation over potential (1.96 V) and reduced the interfacial resistance (5.01 Ω) of the Pr/CDs/SSS/PbO₂ electrode. Significantly, the prepared Pr/CDs/SSS/PbO₂ electrode showed the highest catalytic activity when the electrode was prepared in 5 mmol L⁻¹ of Pr-containing solution, and the degradation of MB by the Pr/CDs/SSS/PbO₂ electrode was 98.2% after 180 min of degradation under the conditions: 50 mg L⁻¹ of MB, pH = 5, and 30 mA cm⁻² of current density. The removal rate of TOC was 58%, which was much higher than that of the pure PbO₂ electrode (3.44%). In general, the Pr/CDs/SSS/PbO₂ electrode can be considered an efficient and low-cost anode material for the electrochemical treatment of organic wastewater.

Two zinc(II) complexes with azopyridine or azopyrimidine featuring dodecyl chains have been synthesized, crystallographically characterized and analyzed in the framework of quantum chemistry. In the mononuclear complex 1, the metal centre has a distorted octahedral geometry with two molecules of 2-(4-dodecyloxyphenylazo)pyrimidine connected in a bidentate fashion, while the remaining coordination sites are occupied by two monodentate nitrate anions. Considering the complex 2, a linear arrangement of three zinc atoms linked by acetate ions was observed. The central zinc atom, situated on the inversion center, is in a nearly perfect octahedral environment, while the outer symmetry-related zinc atoms have a distorted octahedral geometry and they coordinate to three acetate groups and to one molecule of 2-(4-dodecyloxyphenylazo)pyridine in a bidentate manner. In 1, enantiomers locally deracemize so that the coordinated units form homochiral ribbons, while the dodecyl chains from the neighbouring ribbons interdigitate to form layers of molecules. Compound 2 shows a comparable layered packing arrangement. Theoretical investigations of the supramolecular energetic landscape were conducted using density-functional theory (DFT) formalism, quantum theory of atoms in molecules (QTAIM), and natural bond orbital (NBO) computational tools. Quantifying the strength of polar and hydrophobic interactions revealed that H⋯H interactions, hydrophobic in nature, dominate the crystal arrangement of these molecules. The obtained results pave a pathway towards understanding self-organized molecular systems that reach the nano- and micrometer scales.

Atenolol (ATL) is a cardioselective β1-receptor antagonist used to treat cardiovascular disorders such as hypertension and angina. It belongs to the biopharmaceutical classification system (BCS) class III, for which permeation across the intestinal membrane is the rate-limiting step. This study aims to screen biologically acceptable salts of ATL to improve its diffusion properties using six dicarboxylic acids such as oxalic acid (OXA), fumaric acid (FUM), malic acid (MAL), glutaric acid (GLU), adipic acid (ADP) and pimelic acid (PIM). The organic salts were subjected to solid-state characterization such as powder XRD, single crystal XRD, DSC/TGA, and FT-IR spectroscopy. The crystal structures confirm the proton transfer from the carboxylic acid to the isopropyl amine fraction of ATL. Among the multicomponent salts, ATL forms anhydrous salts with GLU/MAL, whereas ATL–OXA/FUM/ADP/PIM are confirmed to be salt hydrates. Similar to the native drug, all the salts maintained stability for more than 1 month during exposure to 35 ± 5 °C/75 ± 5% relative humidity conditions. In addition, the salts were thermally stable at 50 °C for an hour. The aqueous solubility and diffusion study of the ATL salts (ATL–ADP/FUM/PIM/GLU/MAL/OXA) in pH 6.8 phosphate buffer indicated improved solubility (up to 33-fold) and flux (up to 2.8-fold) compared to the native drug due to ionic interactions between the drug and the counterion. Improved diffusion properties of the ATL salts are partially correlated with their enhanced solubility distribution coefficients and log P of the salt former.

Ketanserin (KTS), a BCS class II drug, is used as an alpha-blocking serotonin antagonist. The drug decreases blood pressure by lowering peripheral vascular resistance. In order to improve its poor aqueous solubility, multicomponent solid forms of KTS with aliphatic acidic coformers such as maleic acid (MA), fumaric acid (FA), adipic acid (AA), and sulfamic acid (SA) were synthesized via wet granulation. The salts were characterized by XRD, DSC, TGA and single crystal XRD. Proton transfer from acidic coformers to the most basic piperidine nitrogen atom of KTS confirmed salt formation. KTS·FA and KTS·MA are anhydrous salts, while KTS·SA and KTS·AA are hydrates. KTS·SA crystallized as both monohydrate (MH) and dihydrate (DH), with the dihydrate being the more thermodynamically stable phase. The KTS hydrogen-bonded amide dimer is replaced by piperidinium⋯carboxylate/sulfonate ionic heterosynthons in the salts. Hirshfeld surface analysis quantified the non-covalent interactions governing the salt assembly. Solubility studies in 0.1 N HCl (pH 1.2) and phosphate buffer (pH 6.8) revealed improved solubility for all salts compared to KTS, with the order being KTS·SA (DH) > KTS·FA > KTS·MA > KTS·AA > KTS in phosphate buffer. Slight solubility improvement was observed in acidic medium (pH 1.2). KTS salts maintained their integrity in phosphate buffer but transformed into their HCl salts under acidic conditions. The enhanced solubility of KTS·SA (DH) is attributed to higher ΔpK_a, polar contacts, extended conformation, and ionic heterosynthons. These new solid forms of KTS present an opportunity to overcome solubility-related bioavailability challenges.

Axitinib (AXI) is widely used in the treatment of renal cancer. Due to its molecular structure containing multiple hydrogen bond acceptors and donors, AXI has been reported to exist in five solvent-free polymorphs and over 60 solvates. Among these, form XLI is utilized in clinical treatments due to its stability and efficacy. However, obtaining form XLI through direct solution crystallization is challenging. In this study, a new strategy for the preparation of form XLI was developed, enabling the acquisition of form XLI crystals within a minimum of 140 min via solvent-mediated polymorphic transformation (SMPT) using the AXI S_DMF solvate as the precursor. Powder X-ray diffraction (PXRD) and Raman spectroscopy were used to monitor the SMPT process, revealing that the formation of AXI form XLI strongly depended on the water activity of the solvent system. The dissolution of form IV and the nucleation of form XLI were identified as the rate-limiting steps. Online infrared spectroscopy demonstrated that the solvent environment significantly influenced the polymorphic transformation by affecting the molecular conformation and assembly of AXI in solution. Additionally, the effects of temperature, solid content, and solvent composition on the SMPT process were investigated to enhance control over the transformation. Our study provides an efficient method for the preparation of AXI form XLI.