CrystEngComm最新文献

It is shown that periodic density functional theory (DFT) with hybrid exchange–correlation functionals can be applied to determine the chemical nature of acid–base multicomponent crystals. For a test set of experimentally assigned crystals, the energies of reference “pure” cocrystal and salt forms are calculated in an efficient numerical atomic orbital (NAO) formalism. It is found that energy differences from hybrid DFT can reliably place most of the considered crystals in their assigned chemical class. It is further discussed how DFT has reached the maturity where it may help with the interpretation of ambiguous experimental characterizations and transform how different states along the salt–cocrystal continuum are classified.

In order to overcome the often large activation barriers in heterogeneous catalytic reactions, photocatalysis is a promising path to activate specific molecules with light at moderate temperatures. In particular, bimetallic nanoparticles combining the plasmonic properties of one metal with the high catalytic activity of another are promising antenna–reactor systems. As the nanocrystal surface structure is a major factor in steering surface electronic properties and accompanying activity and selectivity, it is of interest to control the metal nanoparticle growth and composition. The subject of this work is the synthesis of gold–platinum nanoparticles with varying architectures by controlling the growth mechanism. The selection of the reducing agent allows the regulation of the reduction rate of the platinum metal salt, which in turn affects the final morphology of the resulting bimetallic nanoparticles. This allows the synthesis of either core–shell nanocrystals with decorated nanocube corners or dendritic particles under otherwise identical reaction conditions. A dendritic structure requires the rapid deposition of platinum monomers on the surface of the gold particles. This process hinders the diffusion of platinum monomers to energetically preferred sites on the particle surface, which is possible during the formation of core–shell nanocrystals.

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.

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.

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.

Oxychalcogenides have been highly anticipated as nonlinear optical (NLO) crystals because of their excellent optical properties. Herein, a rare-earth oxychalcogenide Eu₂ZnGe₂OS₆ was successfully designed and synthesized. It crystallizes in the non-centrosymmetric P2₁m space group with highly polarized mixed-anion [GeOS₃] units and exhibits an indirect band gap of 2.22 eV, a moderate second harmonic generation (SHG) response (0.4 × AGS), and phase-matching properties. Additionally, Eu₂ZnGe₂OS₆ exhibits a significant calculated birefringence of 0.173@2090 nm. This research has enriched the rarely studied rare-earth oxychalcogenide system and provided new ideas for the design of promising IR NLO crystals.

The systems of intermolecular interactions, including hydrogen bonds, in the crystal structures of the cocrystal of L-ascorbic (L-Asc) and nicotinic (Nic) acids and individual coformers are considered, and the hemolytic and cytotoxic activities of these compounds are studied in vitro. The influence of conformational differences of L-Asc molecules (total effective charge) on the formation of a network of H-bonds in the supramolecular structure of pristine L-Asc is revealed. Calculation of regioselectivity descriptors shows that the conformer of the L-Asc molecule in the L-AscNic cocrystal has higher activity compared to conformer molecules of the pristine L-Asc. No hemolysis caused by the solutions of tested acids and L-AscNic is shown. Selective cytotoxicity (antimetabolic effect according to the MTT test) of solutions of L-AscNic cocrystals against a 72-hour culture of MCF-7 breast cancer cell line versus healthy cells (mesenchymal stem cells and embryonic fibroblasts) is revealed. The possible relationship between the initial conformational state of the L-Asc molecules in the composition/structure of the studied solid compounds and the biological activity of solutions of these compounds requires further studies.