CrystEngComm最新文献

We investigate here the ability of N-iodophthalimide (NIPht) to act as a halogen bond (HaB) donor, in comparison with well-known HaB donors N-iodosuccinimide (NISucc) and N-iodosaccharin (NISacc). The structure of NIPht itself is reported, together with those of neutral adducts with 4-dimethylaminopyridine (DMAP), 4,4′-bipyridine and 2,2′-bipyridine derivatives. Comparison with analogous adducts involving NISucc and NISacc shows that NIPht behaves essentially like NISucc as a HaB donor, both forming weaker adducts than NISacc with a given Lewis base. A symmetric anionic complex [NPht–I–NPht]⁻ is isolated in the presence of [K(18-crown-6)]⁺. It exhibits N–I distances very close to those observed in the known [NSucc–I–NSucc]⁻ and [NSacc–I–NSacc]⁻ species (2.24–2.26 Å), confirming the 3-center–4-electron (3c–4e) character of the bonding in these species. This similarity confirms the peculiar character of the only other reported salt of [NPht–I–NPht]⁻, namely [Me₄N][NPht–I–NPht], where the longer N–I distances (2.29 Å) are a consequence of a specific solid-state arrangement and C–H⋯O hydrogen bonds.

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.

Developing a deep understanding of the fascinating properties of MFM-300 (MFM = Manchester framework material) opens up a world of new and thrilling applications. The unique dynamic metal–ligand bonding for MFM-300(Sc) and MFM-300(In) is chronologically presented here, highlighting the exacting applications that were associated with such special behaviour (i.e., description of complex NH₃ adsorption mechanisms, conversion of toxic H₂S to polysulfides for promising fabrication of lithium–sulphur batteries and heterogeneous catalysis). This highlight aims to showcase the current advances in semi-open metal sites inherent to MFM-300(Sc) and MFM-300(In) to inspire new investigations to be carried out to develop new applications of this promising family of MOF materials.

Based on the viologen ligand 1,1′-bis(3-carboxylatobenzyl)-4,4′-bipyridinium dichloride (H₂BcbpyCl₂) as the functional subject and two aromatic carboxylic acids (m-H₂BDC = 1,3-benzenedicarboxylic acid and H₄BTEC = 1,2,4,5-benzenetetracarboxylic acid) as auxiliary ligands, two Zn(II)-based coordination polymers, formulated as [Zn(Bcbpy)_0.5(m-BDC)]_n (1) and [Zn(Bcbpy)_0.5(BTEC)_0.5(H₂O)]_n (2), have been successfully prepared by solvothermal strategies. Compounds 1 and 2 both have a three-dimensional framework. The two compounds demonstrate reversible photochromic properties owing to the formation of viologen radicals via photoinduced electron transfer. In addition, the photomodulated fluorescence and ink-free erasable printing properties were also studied, which enriched the study of the photophysical properties of the crystals.

Struvite (MgNH₄PO₄·6H₂O) is a mineral first identified in 1845. It is being tested for several reasons: (1) it is a problem in liquid wastewater treatment plants; (2) on the other hand, it is recovered from these wastewaters for its phosphorus, magnesium and nitrogen; (3) is the main component of microbial-induced urinary stones. We have recently shown that struvite is ferroelectric and piezoelectric. In this paper, we present the first experimental evidence of the pyroelectric nature of struvite. Using a single-diffusion gel growth technique, we grew struvite crystals as flat, parallel plates. We performed measurements of pyroelectric currents on struvite of this shape, using it as a dielectric of a plate capacitor. The occurrence of pyroelectric effects in struvite was investigated by measuring depolarization currents as a function of temperature. This technique allows the disclosure of ferroelectric/pyroelectric transitions as well as the reconstruction of the ferroelectric loop. We found that the value of the pyroelectric coefficient p attains a maximum of 22 × 10⁻⁶ C m⁻² K⁻¹ slightly below room temperature, going down to p ≅ 10 × 10⁻⁶ C m⁻² K⁻¹ at room temperature. This value is comparable to values for other minerals. For example, the pyroelectric polarization coefficient of tourmaline, the mineral for which the pyroelectric effect was first discovered, is 4 × 10⁻⁶ C m⁻² K⁻¹. This value is 2.5 times lower than that measured for struvite, illustrating struvite's fairly strong pyroelectricity.

Octacalcium phosphate (OCP) is a fascinating calcium phosphate material with a layered structure that can incorporate various guest molecules, particularly dicarboxylate ions. However, the solution-phase synthesis of OCP fine particles is challenging. In this study, we developed a new precipitation method based on the LaMer model for synthesising fine particles of plain OCP and OCP with incorporated isophthalate and succinate ions. Highly concentrated aqueous solutions and appropriate reaction conditions yielded particle sizes of 100–200 nm for plain OCP and 200–300 nm for OCP with incorporated dicarboxylate ions. The obtained particle sizes were significantly smaller than those of OCPs synthesised using conventional methods. The incorporation of isophthalate and succinate ions into OCP was confirmed using various methods, particularly X-ray diffraction, which revealed expansion of the (100) interplanar spacing. During the synthesis of OCP with incorporated isophthalate ions, hydrolysis of the OCP phase was minimised when the initial pH range of the isophthalic acid solution was 5.2–5.3. Interestingly, OCP with incorporated isophthalate ions exhibited fluorescence (excitation and emission at 325 and 390 nm, respectively), demonstrating the potential of these fine particles as novel biofriendly fluorescent probes. This novel LaMer-model-based synthesis for preparing fine particles of OCP and OCP with incorporated functional carboxylate ions can contribute to the design and development of next-generation biofriendly imaging probes and other functional calcium phosphate materials, such as for use in biosensing and drug delivery applications.

In this study, UiO-66-NH₂ nanoparticles were synthesized via a hydrothermal method, using acetic acid and hydrochloric acid as modulators to optimize the specific surface area and pore width. Oxytetracycline (OTC) was chosen as the test compound to evaluate the adsorption efficiency of UiO-66-NH₂.The material was thoroughly characterized under varying conditions, and the adsorption mechanism was systematically explored through adsorption kinetics, isotherms, and thermodynamic analyses. The results demonstrated that UiO-66-NH₂ exhibited a high OTC adsorption capacity, achieving a maximum of 312.5 mg g⁻¹ under optimal conditions. XRD, TGA, and BET analyses revealed that acetic acid and hydrochloric acid significantly improved the crystallinity and thermal stability of UiO-66-NH₂, increasing the specific surface area from 8.023 m² g⁻¹ to 998.663 m² g⁻¹ and reducing the pore width from 18.783 nm to 2.129 nm. FTIR, XPS, adsorption kinetics, and isotherm studies indicated that the main forces driving OTC adsorption by CMC-Fe were hydrogen bonding, π–π stacking, weak electrostatic interactions, and pore filling. Cyclic adsorption experiments further demonstrated the excellent reusability of UiO-66-NH₂. In summary, the use of acetic acid and hydrochloric acid significantly increased the specific surface area of UiO-66-NH₂, exposing more adsorption sites and playing a critical role in pollutant removal.

Correction for ‘Quadrupolar NMR crystallography guided crystal structure prediction (QNMRX-CSP)’ by Austin A. Peach et al., CrystEngComm, 2024, 26, 4782–4803, https://doi.org/10.1039/D3CE01306E.

Two-dimensional (2D) transition metal chalcogenides (TMDs) have demonstrated immense potential and broad prospects in advancing the fields of next-generation optoelectronics, spintronics, valley electronics, and traditional electronics. In recent years, significant progress has been made in the growth research of TMDs through continuous optimization and innovation of various synthetic strategies. However, precisely controlling the growth conditions of materials, synthesizing high-quality 2D materials with a single domain structure, and achieving the desired shape and performance standards remain complex scientific challenges. Here, we report on the study of MoS₂ nucleation and growth habits by precisely controlling the ratio of molybdenum and sulfur sources during the growth process. Using pre-deposited highly oriented MoO₂ nanorods as templates, two preferentially oriented (0° or 60°) MoS₂ crystal domains were obtained on c-plane sapphire. Characterization using Raman spectroscopy, PL, XPS, and HRTEM reveals that the monolayer MoS₂ continuous film, grown using this templating method, possesses superior quality. Our work demonstrates a method for directional growth of 2D MoS₂ thin films using highly oriented 1D MoO₂ nanorods as templates and precursors, providing new insights into orientation control for epitaxial growth of 2D TMD materials.

In this paper, novel tellurate crystals Lu₂TeO₆ and Nd:Lu₂TeO₆ in a trigonal system are successfully grown by the top-seeded solution growth (TSSG) method using TeO₂ and Li₂CO₃ as fluxes. The full-width at half maximum of the X-ray diffraction rocking curve of the Lu₂TeO₆(100) and (001) wafers are determined to be 37′′ and 47′′, respectively. The transmittance spectra suggest that the Lu₂TeO₆ crystal has a wide transparency window from 0.5 to 6.5 μm. The Lu₂TeO₆ crystal exhibits excellent thermal properties with thermal conductivity coefficients of 2.709 W m⁻¹ K⁻¹ and 3.782 W m⁻¹ K⁻¹ along the a and c axes at 50 °C, respectively. Although the Nd:Lu₂TeO₆ crystal shows small polarized absorption and fluorescence anisotropy with absorption and emission peaks at 808 and 1064 nm, both the absorption and emission peak intensities along the c-axis are significantly higher compared to the a-axis. The spectra and thermal properties indicate that the Lu₂TeO₆ crystal may be a potential laser crystal.