CrystEngComm最新文献

A series of 4-aminopyridinium (4ap) hypodiphosphates has been synthesized and characterized by variable temperature (VT) optical microscopy, thermogravimetry (TGA-DSC) and X-ray diffraction techniques (SC-XRD, PXRD, VT μ-PXRD). Anhydrous salts (4apH)(H₃P₂O₆) (2) and (4apH)₂(H₂P₂O₆) in monoclinic (C2/c) (4), orthorhombic (P2₁2₁2₁) (5) and another monoclinic (Cc) (6) polymorphic modifications were obtained by single crystal-to-powder dehydrations of the hydrates: ionic co-crystal (4apH)₂(H₂P₂O₆)·H₄P₂O₆·2H₂O (1) and salt (4apH)₂(H₂P₂O₆)·2H₂O (3), respectively. Compound (2) was the only anhydrous form which was also obtained by a typical solution-crystallization. Destructive dehydrations strongly affected hypodiphosphate substructures, generating new structural motifs (both in PP–PP and ap–PP interactions) and new crystal architectures, thus revealing the structural diversity in organic hypodiphosphates. Dehydration gave rise to new properties, as non-centrosymmetric and polar anhydrous structures, (5) and (6) respectively, were obtained from centrosymmetric hydrate (3).

Correction for ‘Improving the grindability of rice husk-based green silica through pyrolysis process optimization employing the Taguchi method and response surface methodology’ by Shengwang Yuan et al., CrystEngComm, 2024, 26, 128–142, https://doi.org/10.1039/D3CE01016C.

Postsynthetic modification of porous organic polymers (POPs) facilitates their use to remove toxic gases, such as NH₃. This study conducted a fluorine- and sulfur-targeted postsynthetic modification of POPs to enhance their low-pressure NH₃ adsorption capacity. For the first time, F and S-targeted postsynthetic modification for NH₃ capture using porous adsorbents was demonstrated.

A trifluoropropyl functionalized energetic compound, viz. 3,5-dinitro-1-(3,3,3-trifluoropropyl)-1H-pyrazol-4-amine (TFDNPA), was designed and synthesized, which exhibited potential for TNT replacement as an energetic melt-castable carrier in aluminized explosive formulation due to excellent thermal properties (T_m: 100 °C and T_d: 261 °C), good detonation performance (D: 7330 m s⁻¹ and P: 23.3 GPa), low impact sensitivity (IS: 35 J) and enhanced reaction activity with aluminium powders in melt-cast explosive formulations.

The work presented herein reports on the synthesis, structural and physicochemical characterization and luminescence properties of a family of isostructural coordination polymers (CPs) with a general formula {[Ln(6m2onic)₄Na(H₂O)₃]·8H₂O}_n (where Ln(III) = Nd (1_Nd), Sm (2_Sm), Dy (3_Dy), Er (4_Er), Tm (5_Tm), Yb (6_Yb) and Dy_0.77Eu_0.12Y_0.11 for the multi-metal compound (7_DyEuY) and 6m2onic = 6-methyl-2-oxonicotinate). The crystal structures consist of one-dimensional heterometallic arrays where octacoordinated lanthanide and hexacoordinated sodium centres are sequentially linked and which are held together into a 3D architecture by an extensive hydrogen bonding network formed by the crystallisation water molecules. Photoluminescence measurements in the solid state at variable temperature reveal good properties based on the capacity of the 6m2onic ligand to provide ligand-centred excitation, as suggested by time-dependent density functional theory (TDDFT), and promote efficient energy transfers to the lanthanide(III) ions, to eventually present intense emissions in both the visible and near-infrared (NIR) regions. On the one hand, compound 4_Er displays characteristic lanthanide-centred bands in the NIR region even at room temperature, meaning that the framework is able to isolate the excitons from the vibrational quenching component. On the other hand, regarding the compounds emitting in the visible region, the almost white light emitted by compound 3_Dy with a quantum yield (QY) of 6.2% should be noted. Both a purer white emission and an improved QY (up to 15.8%) may be achieved by means of a doping strategy of europium and yttrium ions into the Dy counterpart. Finally, taking advantage of white light emitted by compound 3_Dy, the chemical and optical stabilities in water have been confirmed by the photophysical study performed in solution.

Heating a single crystal of carbamazepine (III) (the thermodynamically stable form) in contact with solid palmitic acid resulted in the melting of palmitic acid and the growth of the crystals of carbamazepine (II) (the least stable polymorph) at the interface “carbamazepine (III) crystal–palmitic acid melt”. The study suggests a possible mechanism of the transformation of carbamazepine (III) into carbamazepine (II) on mechanical treatment with palmitic acid as an additive.

It is well known that the morphology and structure of electrode materials seriously affect the whole performance of devices. Therefore, transition metal sulfides are desirable cathode materials for supercapacitors due to their high conductivity and rich redox active sites. However, the low energy density restricts their large-scale application. Herein, we design NiMoS@NiCo-LDH core–shell structures through facile synthesis routes. The unique structures relieve volume expansion of the electrode materials during charging/discharging and promote the redox reaction. The as-fabricated products deliver a specific capacity of 1456 C g⁻¹ at 1 A g⁻¹. A flexible device based on the obtained cathode provides an energy density of 80.21 W h kg⁻¹ at a power density of 2698.65 W kg⁻¹. It can maintain 85% of its initial capacity after cycling 10 000 times. Furthermore, they still work stably at extreme temperatures ranging from 25 to −20 °C. The asymmetric supercapacitor (ASC) also presents excellent mechanical durability and stability at different bending angles.

Metallic Ni catalysts often suffer from serious aggregation and poor stability during the process of catalysis. In this work, core–shell nanostructures with nanosized MoO₂–Ni nanoparticles (NPs) and mesoporous SiO₂(mSiO₂) shells were well designed to address these issues. The Ni–MoO₂ hybrid cores were converted from hierarchical NiMoO₄ microtubes inside the SiO₂ shell through carbonization treatment to remove the hexadecyl trimethyl ammonium bromide (CTAB) template under the protection of a nitrogen atmosphere. The mesoporous SiO₂ shells in Ni–MoO₂@mSiO₂ nanoreactors prevented the agglomeration/sintering of Ni NPs, while allowing the mass diffusion of small molecules. Owing to the high catalytic performance of Ni–MoO₂ cores, good protection of mesoporous silica, and the unique sandwich-like structure, the obtained Ni–MoO₂@mSiO₂ nanoreactors showed tremendous improvement in catalytic activity and stability.

Ten novel perrhenates of nitrogenous heterocycles have been generated throughout this investigation. The crystal structure of these compounds was thoroughly examined, and intermolecular non-covalent interactions were analysed using the Hirshfeld surface approach. Organic perrhenate cations interact primarily through intermolecular contacts of the H⋯H, O⋯H/H⋯O, and N⋯H/H⋯N types, whereas anions interact mostly via O⋯H/H⋯O interactions. Six of the eight structures with aromatic fragments had anion–π interactions, whereas four of the 11 structures had anion–anion interactions of the Re–O type. Previously unexplored subtypes of 2D networks composed of interacting tetrahedral perrhenate anions have been discovered in piperazinium and triazolium salts. Thermochemical analysis suggests that Re–O⋯Re anion–anion interactions provide additional stabilisation and impact phase transitions in perrhenates. The consistent patterns of organic salt perrhenate behaviour under MALDI-spectrometry settings have been identified. Characteristic multiplets for rhenium acid salts, which can be designated MALDI fingerprints, have been found. Potential formulae of oxorhenates corresponding to the listed multiplets have been specified.

A family of heteroleptic paddlewheel diruthenium complexes has been designed to obtain a chiral arrangement of the donor atoms of their equatorial ligands around the metal–metal bond axis. In order to do so, the non-symmetric ligands 2-hydroxy-6-methylpyridinate (hmp) and 2-amino-6-methylpyridinate (amp) were employed to obtain the following four axially chiral compounds: cis-[Ru₂Cl(μ-DPhF)₂(μ-hmp)(μ-OAc)] (Ruhmp), cis-[Ru₂Cl(μ-DPhF)₂(μ-amp)(μ-OAc)] (Ruamp), cis-[Ru₂Cl(μ-DAniF)₂(μ-hmp)(μ-OAc)] (Ru′hmp) and cis-[Ru₂Cl(μ-DAniF)₂(μ-amp)(μ-OAc)] (Ru′amp) (DPhF = N,N′-diphenylformamidinate, DAniF = N,N′-bis(p-methoxyphenyl)formamidinate). All the compounds were studied by single crystal X-ray diffraction, confirming that a racemic mixture containing only one of the two possible regioisomers was obtained in all cases. A general nomenclature system for naming the full configuration of intrinsically chiral paddlewheel molecules is proposed using the C/A convention. In addition, electronic spectroscopy and cyclic voltamperometry data demonstrate the electronic tunable nature of this new platform. Overall, these results provide a novel example of robust and tunable chirality, which is of potential interest to be further exploited.