Themed collection Crystal Engineering Techniques

Organic semiconductors are being pursued with vigor for the development of efficient and smart electronics. As a brief tutorial account, we traverse the fundamentals and advancements in the area and provide a crystal engineering perspective.

This highlight presents an overview of pharmaceutical cocrystal production and its potential in reviving problematic properties of drugs in different dosage forms. The challenges and future outlook of its translational development are discussed.

A newly developed methodology allows for the determination of the mechanisms of deformation in flexible crystals with atomic precision. With broader applications, mapping experiments have wide reaching potential within the field of materials science.

Flexible molecular crystals have attracted much attention to unique optoelectronic applications and stimuli-responsive chemistry, resulting in various functional molecular crystals for controlling photons, phonons, electrons, and magnons.

Crystal adaptronics has undergone tremendous developments that have been utilized to rationalize dynamics in crystals. This highlight discusses about the role of intermolecular interactions in rationalizing mechanical responses in crystals.

Stoichiometric variation in organic cocrystals, their synthesis, structure elucidation and properties are discussed. Accountable reasons for the occurrence of such cocrystals are emphasised.

Latency control on the basis of molecular design of a solid state by introducing hydrogen bonding into epoxy curing agents.

Selectivity profiles obtained mechanochemically differ from those obtained in solution, both for selectivity during crystallisation and selectivity by guest exchange.

Solid-state reactions are classified into 10 categories based on the unit cells of the reactant and product.

The visually indistinguishable acicular crystals of a (2S,3R/S)-3-ethyl-1-phenylhex-5-ene-2,3-diol (ephd) diastereomeric pair are separated via the mechanical response based on elastic (2S,3R, right) and brittle (2S,3S, left) crystals.

Two new layered metal phosphate–oxalates were prepared under solvent-free conditions using isonicotinic acid as a structure-directing agent, which show interesting photoluminescence and proton-conducting properties.

We compare the growth of Cs₂AgBiBr₆ crystals by slow and fast evaporation of organic solvents. Using different growth temperatures and precursors enables bridging the gap between the optical properties and applications of Cs₂AgBiBr₆ in solar cells.

Multicomponent crystals of an artemisinin derivative and cinchona alkaloids were produced, combining two major types of antimalaria drugs with unique hydrogen bond interactions. These salts demonstrate a new category of antimalarial pharmaceuticals.

A novel crystal of PTX-2CF₃ exhibits room temperature phosphorescence and mechanical flexibility. This flexible crystal efficiently transduces optical emission both in the straight and bent geometries.

Thermal expansion study has been used to understand the mechanism of elastic bending in 9,10-anthraquinone. Expansion along the bending axis due to bending is expected to resemble the thermal expansion along the same direction.

Charge-transfer (CT) crystals bearing segregated domains between the hexaarylbenzene and TCNQ are a promising platform for developing new organic functional solid-state materials.

When crystallized with the antifungal medication clotrimazole, p-phenylenediamine, the most prominent hair developer used in the hair dye industry today, is oxidized to its trimeric product Bandrowski's base, and forms a cocrystal.

The torsional flexibility of imines affects solid-state packing and properties. Behaviors including colossal thermal expansion, pedal motion, and phase transitions in imine-containing solids are described.

The arrangement of paracetamol templated by the structure of 1 : 1 co-crystal of paracetamol–maleic acid in solution phase facilitating the nucleation of metastable form II paracetamol.

UV irradiation of a unique ladder-like coordination polymer affords a two-dimensional coordination network through single-crystal to single-crystal photocycloaddition reaction.

Neutron powder diffraction analysis revealed that ceria transformed into the oxyhydroxide structure by hydrogen treatment.

Pinkish purple rhodamine B polluted water was efficiently photodegraded into colorless by the GeSe MAB crystal-based film under sunlight irradiation.

Snowflake metallocene@MOF-derived ammonia catalyst.

Photo-sensitive tropolone was stabilized by rebalancing the electron distribution of the reactive system.

Phase transformation of ISV solid forms during dissolution.

Intensification of upconversion luminescence (UCL) from a single phase NIR-upconverting (UC) crystal due to perturbation of the local symmetry field may not always manifest through average structural attributes like lattice parameters.

The strong influence of MoO₃ chemical purity from 99.99 wt% to 99.999 wt% on lithium triborate (LBO) and NaLa(MoO₄)₂ crystal growth as well as on OLED technologies has been demonstrated.

A series of solvatomorphic structures of tetrakis(4-dihydroxyborylphenyl)adamantane were investigated.

Repeated crystallization or the use of different chemicals to obtain a pure crystal can cause yield/purity issues.

Transformation of laterally grown ZnO nanofins by replacing Zn with Ga via the “Kirkendall Effect”.

The relationships between the shape and cell parameters were investigated using 131 crystals of secondary aromatic sulfonamides. And, 11 sulfonamides isolated as oils, amorphous, or needle crystals were co-crystallized to obtain block-like crystals.

Suvorexant (SRX) is a dual orexin receptor antagonist used for the treatment of insomnia.

In this study, we synthesized numerous Co–Mo–S nanosheet networks as electrode materials by a two-step hydrothermal strategy. It delivers a specific capacity of 510 C g⁻¹ at 1 A g⁻¹.

α-MnO₂ nanowires with different crystal facets were synthesized. The (110) crystal facet of α-MnO₂ is conducive to propane catalysis, due to the lowest electron energy, effectively Mn valence adjustment and abundant oxygen vacancies.

Two new Cd(II)-MOFs are hydrothermally synthesized and can be applied as dual-response sensors to identify Fe³⁺ and levofloxacin (LVX) with high selectivity, sensitivity and excellent reusability.

Creation of isostructural systems is a balance between thermodynamic and kinetic factors, shown by a set of substituted quinoxalines, where the lighter halogens form a set of metastable isostructural crystals, different to the heavy substitutions.

Three novel Zintl phases in the Ca_11−xGd_xSb_10−y system were synthesized, and the early stage of the single-crystal growth process and the “tipping point” of the cationic site preference for the size-factor criterion were thoroughly investigated.

The anti-HIV pharmaceutical efavirenz is highly dynamic in its crystalline state, and we show that these dynamics can be tamed through the introduction of a coformer.

Compared with clotrimazole, some multicomponent crystals showed an improvement in solubility and dissolution rate.

Salts of quinine, with α,ω-aliphatic dicarboxylic acids, and aromatic coformers, show superior aqueous solubility. The structural, thermal and microscopy data provide structural, compositional, and stability profiles of the salts.

The first two 3D cesium containing manganese vanadates were synthesized by using K₂Mn(VO₃)₄ as the precursory reactant in concentrated Cs⁺ aqueous solutions.

A new non-centrosymmetric K₂Ca₃(CO₃)₄ crystal (P2₁2₁2₁, a = 7.39134(18) Å, b = 8.8153(2) Å, c = 16.4803(4) Å) was synthesized in a multi-anvil press at a pressure of 3 GPa and temperature of 975 °C.

Copper enters the channels of the Ba₁₂(BO₃)₆[BO₃][LiF₄] structure both in the mono- and bivalent states and creates effective luminescence and capture centers. The influence of co-doping with REEs and strontium on properties has been investigated.

A series of charge transfer complexes (CTCs) were successfully formed by solvent free processing techniques, using the 1,2,4,5-tetracyano benzene (TCNB) as π_A molecule and a series of p-dihydroquinones (H₂Qs) as π_D counterparts.

Three novel Co(II)-based MOFs, having structural diversities and various properties are successfully synthesized.

Racemic crystals of Cu/Zn(II)-tetradentate Schiff base ligands with Λ/Δ-chirality induction at-metal center.

(0001)-Oriented epitaxial YbFe₂O_4−δ films without twin domains were formed on YSZ (111) substrates. The charge ordered structure and the large magnetization comparable to bulk single crystals were confirmed on the films.

The improved solubility of two salts of dapsone (DAP) was investigated from the view point of structures and hydrogen bonding.

Eight cocrystal-salts of the multi-kinase drug pazopanib with hydroxybenzoic acids are sustained by the strong, ionic aminopyridinium⋯carboxylate heterosynthon of N–H⋯O hydrogen bonds between the carboxylic acid donor and amino-pyrimidine acceptor.

A novel monohydrated molecular salt of GABA with L-tartaric acid was crystallized and investigated.

The ability to selectively tune the optical and the mechanical properties of organic molecular crystals offers a promising approach towards developing flexible optical devices.

Atomic force microscopy was used to determine roughness, elastic modulus and work function after thermally-induced and solvent-induced dehydration. These properties correlated with electric charging to provide insight into behaviour of bulk powders.

Photoinduced topographical changes, bending, and photosalient effect due to the dimerization reaction were observed on a single crystal of 7-methoxycoumarin, upon deep UV (254 nm) light irradiation.

We report here a new green fluorescent organic crystal of an amide functionalized acrylonitrile derivative (E-ArF₂) that displays various types of macroscopic response when illuminated with UV light (390 nm).

The higher the number of fluorine atoms, the higher the topological photo-induced [2 + 2] cycloaddition reactivity of chalcones.

The bending deflection and blocking force of photo-bending crystals of different sizes were experimentally measured at various light intensities, and then modeled by the machine learning-based regression.

Two epimeric series of esters exhibit distinct mechanical behaviour: brittle crystals for one series and ductile crystals for the other series.

Nanoindentation measurements in single crystals of carbamazepine form III show that the (020) face is stiffer and harder than the (002) and (101) faces. AFM imaging and molecular simulations reveal that the (020) plane is the most likely slip plane.

Broadband NIR luminescence from the Li₃Mg₂NbO₆:Cr³⁺ phosphor is related to the multi-site occupation behavior of Cr³⁺.

This figure shows the emission spectra of nanocrystals with different Li⁺ ion introducing concentrations at 1550 nm. Compared with the untreated samples, when the Li⁺ ion introducing concentration is 0.2 mol%, the luminescence intensity of the sample is improved obviously.

Three cocrystals of axitinib were prepared, and they demonstrated a significantly improved apparent solubility and dissolution rate without compromising physical stability.

X-ray structure analyses of co-crystals of H₂O₂ and L-Phe, DL-Phe, or DL-Asp prepared in a dilute aqueous solution (30 wt%) indicated that multi-layer motifs including water molecule is important for highly efficient H₂O₂ capture in dilute solutions.

Atomic bonding with simple 1D spring and ball model for the phonon–phonon interaction, which arises from 5s² lone pair electrons.

Imino-bridged symmetric N-rich energetic materials with high energetics and good stability.

Investigation into the effect of different nucleation mechanisms on the nucleation rate for paracetamol crystallization in stirred microvials.

The smaller the proportion of the chelated ligand, the more water molecules in the compound, which increases the chance of forming continuous hydrogen bonds, enhances the water absorption ability, and improves the proton conductivity of the compound.

This research work deals with the unprecedented copper(II) induced nucleophilic cleavage of a quinoxaline heterocycle with spectroscopic, structural and computational studies.

Photomechanical responses of the single crystals of a series of sulfonylhydrazones are explored for the first time.

1-pentanol, long-chain alcohol molecule, can be encaged in the clathrate hydrate by managing the destabilizing influence of guest–host hydrogen bonding.

Paramagnetic suppression in TTTA at pressure is caused by a steady decrease in the separation between moieties containing the radical electron along π-stacking chains with no phase transition.