CrystEngComm最新文献

Calcium oxalate (CaOx) crystallization under laminar flow conditions, relevant for kidney stone formation, was studied in a microfluidic device simulating the geometry of kidney collecting ducts. In a typical microfluidic experiment, two reactive solutions with designated concentrations of calcium (Ca) and oxalate (Ox) ions were brought into contact in a microfluidic channel to create a laminar co-current flow of the two streams. As the streams flow co-currently in the channel, diffusion takes place between the two streams across the channel width, resulting in reactive crystallization leading to CaOx nucleation and growth of CaOx crystals along the mixing front. We studied the growth of these crystals in artificial urine as a function of the fluid flow rate in the channel, the molar ratio of Ca : Ox in the medium and the presence of an organic protein, osteopontin (OPN), known to inhibit the growth of CaOx crystals. Three different flow velocities at a fixed molar ratio of Ca : Ox = 7.5 and four molar ratios of Ca : Ox at a fixed mean flow velocity of 0.035 m s⁻¹ were tested. Lastly, three additive OPN concentrations were evaluated: 2.4 × 10⁻⁸ mol m⁻³, 6 × 10⁻⁸ mol m⁻³ and 8.4 × 10⁻⁸ mol m⁻³. The mean flow velocity did not alter the crystal growth of CaOx in the studied range, whereas altering the molar ratio of Ca : Ox had a high impact on the growth rate. In addition, the type of pseudopolymorph which nucleated appears to depend strongly on the molar ratio. At a low Ca : Ox ratio, both calcium oxalate monohydrate (COM) and calcium oxalate dihydrate (COD) nucleated simultaneously and the growth of the two pseudopolymorphic forms of CaOx crystals was observed. The lowest applied OPN concentration decreased the growth rate of COD, while higher concentrations of OPN slowed down the nucleation kinetics to a point that it completely inhibited the formation of any CaOx crystal in artificial urine within the investigated timeframe. COD was seen under all the conditions investigated, whilst COM was seen in experiments for Ca : Ox molar ratio values between 5 and 6. Our results were rationalized using finite element simulations supported by solution chemistry modelling.

Ammonium dinitramide (ADN) is highly hygroscopic which poses significant challenges in its practical applications. Consequently, mitigating this hygroscopic nature has been a primary focus in the research and development of ADN. This study investigated the properties of the ADN/3-amino-5-nitro-1,2,4-triazole (ANTA) cocrystal using density functional theory, molecular dynamics, and Monte Carlo methods. The research involved analyzing binding energies, radial distribution functions, and molecular interaction energies, predicting the crystallographic properties of the cocrystal, and theoretically assessing the hygroscopicity of ADN, stability and detonation properties. The results indicated that the cocrystal achieved relative stability at a 1 : 1 molar ratio of ADN to ANTA, driven by favorable conditions for cocrystal formation. The primary forces facilitating this cocrystal formation were hydrogen bonds and van der Waals interactions. The predicted space group for the cocrystal was P, with a calculated crystal density of 1.8353 g cm⁻³. Additionally, the cocrystal demonstrated a calculated saturated moisture absorption rate of 3.67%, which contrasted significantly with the 18.12% absorption rate observed for pure ADN. The cohesive energy density and trigger bond length indicated that the stability of the ADN/ANTA cocrystal was higher than that of ADN. Theoretical calculations indicated that the detonation performance of the cocrystal is close to that of the pure component ADN, suggesting that the ADN/ANTA cocrystal is a new type of high-energy material with low hygroscopicity.

Propranolol is a popular active pharmaceutical ingredient (API), a competitive non-cardioselective sympatholytic beta blocker, listed in the WHO Model List of Essential Medicines. Although, since its invention in 1962, multiple salts and cocrystals of propranolol have been obtained, in most of the commercially available drugs it exists in a form of racemic hydrochloride. Inconsistency exists in the previously deposited crystal structures of this salt, with some of them indicating structural disorder. Therefore, in this work the single crystal X-ray diffraction, solid state NMR and CASTEP periodic DFT calculations were combined to explain this phenomenon and characterize the crystal structure of this API. The obtained results clearly indicate the presence of static disorder in the crystal structure, pointing the most favorable arrangements. Besides, the comparison with the results obtained for the structures of pure enantiomers explained why the studied API forms racemic systems instead of complete chiral discrimination in the solid state.

Ball milling an equimolar ratio of melamine and barbiturate under liquid assisted grinding (LAG) with acetonitrile forms a rosette co-crystal (form A), while under neat grinding (NG) forms an amorphous form. A new co-crystal (form B) is formed from form A or from the amorphous form by LAG with water. The 2 crystalline polymorphs and the amorphous form can be interconverted by ball milling under the conditions favouring their formation. Surprisingly, on milling the co-formers with water, we obtained a linear tape co-crystal (form C), leading to the disappearance of form B. Form C takes now the role previously executed by form B in the reversible turnover cycle. This work is the experimental evidence that full reversibility between multiple phases under milling conditions is a general phenomenon.

Correction for ‘Revealing the supramolecular features of two Zn(II) complexes derived from a new hydrazone ligand: a combined crystallographic, theoretical and antibacterial study’ by Samit Pramanik et al., CrystEngComm, 2023, 25, 866–876, https://doi.org/10.1039/D2CE01445A.

Correction for ‘Influence of cobalt on the performance of Pt/CeO₂ for CO-PROX at low temperature: reducing the energy of the Pt–O–Ce bond’ by Ao Xu et al., CrystEngComm, 2024, 26, 6493–6500, https://doi.org/10.1039/D4CE00868E.

A rapid co-reduction strategy for the synthesis of ultrafine and composition-tunable multi-principal element alloy catalysts is proposed. This method necessitates only a 10-minute reaction time at 180 °C and features straightforward setups. The as-synthesized carbon-supported RuPtIrSnCu nanoparticles exhibit superior hydrogen evolution reaction performance in acidic media due to synergistic effects among their multiple components.

Diastereomeric salt formation is suitable for chiral resolution of racemic compounds and is the most effective way to obtain enantiomers. At present, there are few resolution methods for DL-leucine (DL-LEU), and the corresponding mechanism of resolution has not been studied. In this study, (+)-di-1,4-toluoyl-D-tartaric acid monohydrate (D-DTTA) was selected as the ligand. Diastereomeric salts D-LEU:D-DTTA (D–D) and L-LEU:D-DTTA (L–D) were synthesized by liquid-assisted grinding and then identified by powder X-ray diffraction, thermal analysis, Fourier transform infrared spectroscopy and single crystal X-ray diffraction. Their difference in crystal structures, thermodynamic properties and intermolecular interactions showed that D–D is more stable and has lower solubility, which makes chiral resolution possible. Furthermore, the mechanism of chiral recognition was investigated, which showed that D-DTTA was more easily bound to D-LEU. Finally, the optimized resolution condition was confirmed, and the ee values of D–D and L–D reached 91.20% and −73.32% respectively by the multi-stage crystallization process. This study provides an effective and industrially applicable method for the separation of the DL-LEU racemic compound, and provides a reference for the screening of salt-forming chiral resolution agents.

A novel bis-(1,2,4-triazolyl)-furoxan structure for balancing energy and sensitivity has been successfully achieved. Theoretical calculations and impact sensitivity tests show that bis-(2-methy-3-nitroamine-1,2,4-triazolyl)-furoxan and bis-(2-methy-3-amine-1,2,4-triazolyl)-furoxan of two energetic compounds exhibit outstanding denotation performance (8.1 km s⁻¹) and excellent impact sensitivity properties (>25 J). It is demonstrated that the graphene-like layered stacking structure of novel bis-(1,2,4-triazole)-furoxan compounds is due to intramolecular interactions and intermolecular interactions by combining structure description with wavefunction analysis (Hirshfeld surface analysis, IRI analysis, IGMH analysis, AIM analysis, etc.). Numerous experiments have shown that 3-nitro-5-chloroxime-1,2,4-triazole or 3-nitroamino-5-chloroxime-1,2,4-triazole of two intermediate compounds is unable to obtain bis-triazole-furoxan under alkaline conditions. N-methylation of the triazole was accomplished by protecting the amino group with dimethylformamide dimethylacetal, facilitating furoxan synthesis. This study first introduces the electrostatic potential isosurface distribution of clusters within crystals in analysing energetic compounds. The results show that the electrostatic potential distribution of clusters is more regular than individual molecules, which could be significant for predicting and assessing the sensitivity of energetic compounds.

Crystal growth in water between lanthanide ions and tetra-chloro-benzene-1,2-di-carboxylate (tcpa²⁻) led to 6 new coordination compounds with respective chemical formulas [Y(tcpa)(OH)(H₂O)₃]_∞ (1), Nd₄(tcpa)₆(H₂O)₂₂·8H₂O (2), [KLa(tcpa)₂(H₂O)₁₀·H₂O]_∞ (3), [KLa(tcpa)₂(H₂O)₅·2H₂O]_∞ (4), Y(tcpa)(Htcpa)(H₂O)₅ (5) and [KTb(tcpa)₂(H₂O)₆·H₂O]_∞ (6). The crystal structures of these six compounds are described and compared with previously described crystal structures, focusing on the structural characteristics that are known for being key points for luminescence intensity. Trends induced by the presence of halogen atoms are identified.