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In the current study, the most stable optimized structure of the named compound 5-(furan-2-ylmethylidene) thiazolo[3,4-a] benzimidazole-2-thione (FThBZ) was determined using the B3LYP/6-311++G(d,p) basis set. The nature of molecular interactions between molecules in the crystal via different type of bonds was investigated using Lattice Energy analysis and non-covalent reduced density gradient (NC-RDG) and Fukui functions are performed to study the chemical reactivity of the compound. The dipole moment values, first and second order polarizability and hyperpolarizability of the title compound were calculated. A symptom of Alzheimer's is the appearance of amyloid plaques, or senile plaques: made up of aggregates of beta-amyloid peptide between nerve cells. To overcome this effect, there is a need for a potent and effective inhibitor that inhibits the proper functioning of amyloid precursor protein (APP). In this regard, we conducted an in silico docking and molecular dynamics simulation study. [ABSTRACT FROM AUTHOR]

In this work, the structure of a CrMnFeCoNiCu high-entropy alloy (HEA) film deposited by magnetron evaporation on a steel substrate is studied. It is established that the phase content of the CrMnFeCoNiCu HEAs is determined by a superposition of contributions from equiatomic simple cubic lattices of the CrMnFeCoNiCu composition (Struct-26 and Struct-278) with space group P1. It is found that the contributions of the diffraction patterns from the reference lattices to the integral intensity are 0.66 and 0.29, respectively. For simple cubic lattices Struct-26 and Struct-278, the full structural information (the lattice parameters, coordinates of atoms, spatial groups, and occupancies) is derived. It is established that the CrMnFeCoNiCu HEA is a stable compound, which is confirmed by calculations of the mixing energy for the convex Hull model. [ABSTRACT FROM AUTHOR]

A simple, efficient, direct and economical method for the mutual separation of Nd and Pr was developed by the selective dissolution of Nd2O3 from their oxide mixtures in an ionic liquid containing 2‐thenoyltrifluoroacetone (HTTA) resulting in an unprecedented separation factor (βNd/Pr)>500, which is 277 times more than the thus far reported βNd/Pr values. The proposed mechanism was supported by DFT computations. [ABSTRACT FROM AUTHOR]

In this study, we synthesized BaZnSi3O8‐based compounds with monoclinic structures (P21/a) using a solid‐state method. The crystal structure, phase composition, and microwave dielectric properties of BaZnSi3O8‐based ceramics were systematically investigated systematically. X‐ray diffraction (XRD) patterns and scanning electron microscopy (SEM) images proved that the maximum solubility of BaZn1‐xMgxSi3O8 ranged between 0.3 and 0.4. Rietveld refinement and Phillips–Van Vechten–Levine complex chemical bond theory were used to illustrate the relationship between the microwave dielectric performance and lattice parameters. To further improve the properties, we substituted Ba2+ with Sr2+ in BaZn0.8Mg0.2Si3O8. Ba1‐ySryZn0.8Mg0.2Si3O8 remained in a single‐phase as y increased from 0 to 1.0. We achieved thermal stability of the resonance frequency of the BaZnSi3O8‐based ceramics by adjusting TiO2 to form composite ceramics. After sintering at 1020°C for 5 h, excellent microwave dielectric properties with εr = 7.44, Q×f = 57,400 GHz, and τf = − 0.2 ppm/°C were realized in the SrZn0.8Mg0.2Si3O8+8 wt %TiO2 system. [ABSTRACT FROM AUTHOR]

The calculation of intermolecular interactions in molecular crystals using model energies provides a unified route to understanding the complex interplay of driving forces in crystallization, elastic properties and more. Presented here is a new single-parameter interaction energy model (CE-1p), extending the previous CrystalExplorer energy model and calibrated using density functional theory (DFT) calculations at the ωB97M-V/def2-QZVP level over 1157 intermolecular interactions from 147 crystal structures. The new model incorporates an improved treatment of dispersion interactions and polarizabilities using the exchange-hole dipole model (XDM), along with the use of effective core potentials (ECPs), facilitating application to molecules containing elements across the periodic table (from H to Rn). This new model is validated against high-level reference data with outstanding performance, comparable to state-of-the-art DFT methods for molecular crystal lattice energies over the X23 set (mean absolute deviation 3.6 kJ mol−1) and for intermolecular interactions in the S66x8 benchmark set (root mean-square deviation 3.3 kJ mol−1). The performance of this model is further examined compared to the GFN2-xTB tight-binding model, providing recommendations for the evaluation of intermolecular interactions in molecular crystal systems.

The Structural factors of ceramic materials significantly affect microwave dielectric properties. Consequently, the structure–performance mechanism is essential for providing insight into material discovery and performance refinement. In the present work, Zn 1- x Cu x ZrNb 2 O 8 ceramics were synthesized through oxygen-assisted sintering procedures. The controversy of lattice vibrations was clarified and complete Raman vibration with complete mode assignments were provided for the first time through density functional theory and symmetry analysis. Intrinsic properties, including lattice energy, bond ionicity, thermal expansion coefficient, Raman vibrational states and bond energy, were calculated and the structure–performance relationships were established based on crystal structure refinement, density functional theory, chemical bond theory and Raman analyses. X-ray diffraction patterns and crystal structure refinement indicate a pure phase with the wolframite structure. The smaller ionic radii of Cu2+ ions led to a decrease in cell volume, which could account for the blueshift of the Ag mode at around 340 cm−1. Through Cu2+ substitution, the grain growth was further promoted and morphology evolution from polyhedral grain to rod shape was observed, which may be attributed to grain amalgamation. From chemical bond theory, Cu2+ substitution leads to the decrease in the dielectric constant, which is related to a decrease in the Nb–O bond ionicity (fiNb-O). The improvement in Q×f value is attributed to the high lattice energy of Nb–O bond (UNb–O), low FWHM at 845 cm−1 and large grain size. τ f values are strongly impacted by the bond energies of the Zn/Cu–O bonds in the Zn 1- x Cu x ZrNb 2 O 8 ceramic crystals. Remarkably, microwave dielectric performance of the composition x = 0.06, sintered at 1175 °C, where ε r = 27.9, Q×f = 73,200 GHz (@7.14 GHz) and τ f = −40 ppm/°C, provide potential for millimeter-wave applications. [ABSTRACT FROM AUTHOR]

The disposal of high-level nuclear waste (HLW) presents major challenges due to the presence of a wide range of long-lived radionuclides, necessitating the development of an effective and safe disposal strategy. SrLnTh(PO4)3 (Ln = La–Gd) system was examined to understand the impact of lanthanides on the structure and thermodynamic stability as a host matrix for HLW immobilisation. Solid-state method was used for the synthesis and, powder X-ray diffraction with infrared spectroscopy techniques for their characterization. All compounds were found to crystallize in monazite-type phase with cations Mn+ (Sr2+, Ln3+ and Th4+) randomly occupying the same lattice site, forming MO9 polyhedron. Heat capacities were measured using differential scanning calorimeter. Dissolution enthalpies were measured using solution calorimeter in lead-borate solvent kept at 1067 K and used for determination of enthalpy of formation of the compounds from their constituent oxides ( Δ H f-ox o ) and elements ( Δ H f-ele o ) at 298 K. The results indicate that the enthalpy of formation progressively becomes less exothermic from La3+ to Gd3+ ions, which is also supported by lattice energy calculation using Born–Haber cycle. [ABSTRACT FROM AUTHOR]

Some amino acid systems are known to exhibit solid solution and/or co-crystal behavior upon crystallization, which significantly affects their phase diagrams and complicates the design of their purification processes. Such behaviors are observed in the l-valine/l-leucine system. In this work, the formation and stability of a 3:1 co-crystal of the two amino acids (designated as V3L) is further investigated. To accomplish the formation, liquid-assisted grinding, slurry equilibration, and sublimation experiments were performed and analyzed via HPLC and PXRD. Additionally, periodic DFT calculations were used to calculate lattice energies and determine the thermodynamics of possible solid phases. Experimental results show a clear metastability of the investigated V3L co-crystals when compared to its stable solid solution. The calculations underline the metastability and the possible formation of continuous solid solutions between l-valine and l-leucine since lattice energy differences between pure amino acids and mixed compositions are negligible. This previously unknown phase behavior can be used to assess the influence of V3L on the amino acid purification process and provides a basis for investigating similar systems with small energy differences between pure and mixed compositions in future studies. In addition, it demonstrates the particular variability of solid phases and their relationships in such simple but biologically important amino acid systems. [ABSTRACT FROM AUTHOR]

Roseolumiflavin is a deep red microcrystalline derivative of isoalloxazine that exhibits a weak photophysical activity in the solid state. In aqueous as well as in acidic solution of formic or acetic acid, respectively, it tends to form solvates. Herein, we present a set of binary and ternary roseolumiflavin solvates including one hydrate and a solvate hydrate. The impact of the solvent on solvate formation along with an in-depth structural analysis was investigated. Calculations of the lattice energies provide insight into the phase stability of the evaluated systems showing an energetic benefit for all solvates with values up to −395.82 kJ/mol. The total interaction energies between molecules calculated via Crystal Explorer further identified cofacial π···π stacks to be the most strongly bonding fragments in the crystal lattices for all systems except the formic acid solvate, followed by remarkably weaker hydrogen-bonded arrangements. The energetic contributions of single intermolecular interactions within the fragments are evaluated by an atoms-in-molecules approach. It is shown that physicochemical properties, such as thermal stability, can be tuned depending on the incorporated solvent molecules despite a high decomposition temperature of the chromophore. [ABSTRACT FROM AUTHOR]

MgTi1−x(Mn1/3Nb2/3)xO3 (x = 0–0.30) ceramics were prepared via the solid-state reaction method. The phase composition, microstructure, bond characteristics, and microwave dielectric properties of MgTi1−x(Mn1/3Nb2/3)xO3 (x = 0–0.30) were systematically investigated. The MgTi1−x(Mn1/3Nb2/3)xO3 ceramics presented an ilmenite type with an R-3 space group, and the secondary-phase MgTi2O5 only existed at x = 0 and 0.30. The introduction of (Mn1/3Nb2/3)4+ effectively suppressed the formation of the MgTi2O5 phase. The variation trend of the dielectric constant (εr) was the same as relative density. The quality factor (Qf) value was enhanced by the stable microstructure, which was caused via the lattice energy of Ti/(Mn1/3Nb2/3)-O bonds. And a high Qf value (353,000 GHz) was obtained for MgTi1−x(Mn1/3Nb2/3)xO3 (x = 0.04) ceramics sintered at 1250 °C. In addition, the introduction of Mn2+ ions with a larger ionic radius exacerbates the distortion of TiO6 octahedra, leading to significant fluctuations in the temperature coefficient of the resonance frequency (τf) value. [ABSTRACT FROM AUTHOR]

Two monoclinic (P21/c; Z′ = 1) polymorphs, α (from methanol) and β (from ethanol, n-propanol and iso-propanol), of a bioactive pyrazolo[3,4-d]pyrimidine derivative have been isolated and characterised by X-ray crystallography as well as by a range of computational chemistry techniques. The different conformations observed for the molecules in the crystals are due to the dictates of molecular packing as revealed by geometry-optimisation calculations. The crucial difference in the molecular packing pertains to the formation of phenylamino-N–H···N(pyrazolyl) hydrogen bonding within supramolecular chains with either helical (α-form; 21-screw symmetry) or zigzag (β-form; glide symmetry). As a consequence, the molecular packing is quite distinct in the polymorphs. Lattice energy calculations indicate the β-form is more stable by 11 kJ/mol than the α-form. [ABSTRACT FROM AUTHOR]

In the present study, we use high-level coupled-cluster-based methods to obtain benchmark geometries and lattice energy for small sodium chloride clusters up to (NaCl)15. Reliable geometries can be obtained with the CCSD(T)-F12b method in conjunction with a small double-ζ basis set, while accurate energies can be obtained with relatively economical methods (e.g. DLPNO-CCSD(T1)-F12) by adjusting for systematic bias against higher-level methods (e.g. W2). For the calculation of larger clusters, we find PBE0-D3BJ and GFN1-XTB to be suitable for geometry optimisation, while B97M-V and GFN1-XTB provide an adequate means for energy calculations once they are calibrated against high-level references. For much larger systems, a Born–Landé-type model can be used to obtain fairly good lattice energies. The results show the progression from a single NaCl molecule to bulk salt, with full convergence expected for cluster sizes in the range of 5–10 nm. The protocol for obtaining highly accurate lattice energies and calculating large clusters may be used to examine the energetics of ionic clusters more generally. [ABSTRACT FROM AUTHOR]

Testosterone (17β-Hydroxyandrost-4-en-3-one) is the primary male anabolic-androgenic steroid. The crystal structures of two medium and two long esterified forms of testosterone, including enanthate, cypionate, decanoate and undecanoate, were determined by X-ray single crystal diffraction. The samples were also characterized by powder X-ray diffraction, FT-IR spectroscopy and thermal analysis (DTA, TG). Crystal packings and supramolecular features were described. The analysis of structural features was accomplished by computational methods in terms of the type of intermolecular interactions, crystal energies and Hirshfeld surfaces analysis. From a pharmaceutical point of view, the solubility of compounds was investigated. [ABSTRACT FROM AUTHOR]

How to search for a convenient method without a complicated calculation process to predict the physicochemical properties of inorganic crystals through a simple micro-parameter is a greatly important issue in the field of materials science. Herein, this paper presents a new and facile technique for the comprehensive estimation of lattice energy (U), bulk modulus (B), chemical hardness (ƞ), and electronic polarizability (α), just by using a simple mathematic fitting formula with a few structure parameters, such as the systems of rock salt crystals (group I–VII, II–VI) and tetrahedral coordinated crystals (group II–VI, III–V). For the typical binary ANB8-N crystal systems, our present conclusions suggest that a good quantitative correlation between U, B, ƞ, α and chemical bond length (d) is observed, the normal mathematical expression is P = a·db (P represents these physicochemical parameters), constants a and b depend on the type of crystals, and the relevant squares of the correlation coefficient (R2) are larger than 0.9. The results indicate that lattice energy, bulk modulus, and chemical hardness decrease with increases in chemical bond length, but electronic polarizability increases with an increase in chemical bond length. Meanwhile, the new data on the lattice energy, bulk modulus, chemical hardness, and electronic polarizability values of binary ANB8-N crystal systems considered in the present study are calculated via the obtained curve fitting equations without any complex calculation process. We find that there is a very good linear trend in our calculated results along with the values reported in the literature. The present study will be important in solid-state chemistry, which may give researchers useful guidance in searching for relevant data for predicting the properties of new materials or synthetic routes based on a simple mathematic empirical model. [ABSTRACT FROM AUTHOR]

A survey of those standard inorganic materials which boil without sublimation or decomposition has yielded data for 110 unique materials. These separate according to their ambient lattice energies into groups of monohalides, dihalides, trihalides, tetrahalides and lanthanoid oxides. A wide range of boiling points occurs within each group. The lanthanoid oxides have exceptionally high boiling points which are linearly related to the atomic numbers of their lanthanoid cations through their atomic masses.

Single crystals of two polymorphic forms of 4′-methyl-2,4-dinitrodiphenylamine were obtained by crystallization and characterized by X-ray diffraction analysis. One of the forms is non-centrosymmetric (space group P21212), while the second is centrosymmetric (space group P¯1) and contains two crystallographically independent molecules in the asymmetric unit. In both forms, the same supramolecular synthon, a dimer linked by bonding N-H···O, O···O, and C-H···O interactions were found. Despite nearly the same connectivity of the bonding interactions, the conformation of the supramolecular synthon is different, including its unavoidably different symmetry in two polymorphs. The comparison of the crystal packing of the orthorhombic polymorph with that of the related 2,4-dinitrodiphenylamine (space group P21/n) shows the quasi-isostructurality of the fragments, infinite π-stacks joined by weak non-directional intermolecular interactions. However, the fragments are linked by the supramolecular synthons via either a two-fold axis or an inversion center, which lead to only the partial isostructurality of the crystals. [ABSTRACT FROM AUTHOR]

Colourless single crystals of Ge(SO4)2 were obtained as single phase products from the binary oxides GeO2 and SO3. The reaction was carried out in a silica glass ampule enclosed in an autoclave at 350 °C. Ge(SO4)2 forms a layer structure with corner‐linked GeO6 octahedra and SO4 tetrahedra. The crystal structure (R3‾ ${\bar{3}}$ c, Z=6, a=4.622 Å, c=42.576 Å) belongs to the Ni(ClO4)2‐type. The SO4 tetrahedra are rotated by 24°. The sense of rotation alternates between adjacent layers. This rotation is connected to a super structure with a doubled c‐axis and a disorder between the layers according to the sense of rotation. Ge(SO4)2 is one of the very rare examples of a sulphate of a tetravalent cation and is the representative with the smallest ionic radius. Lattice energy calculations confirm the electrostatic consistency. Vibrational spectra were recorded and show the typical features of GeO6 and SO4 units. [ABSTRACT FROM AUTHOR]

Colourless single crystals of Ge(SO4)2 were obtained as single phase products from the binary oxides GeO2 and SO3. The reaction was carried out in a silica glass ampule enclosed in an autoclave at 350 °C. Ge(SO4)2 forms a layer structure with corner‐linked GeO6 octahedra and SO4 tetrahedra. The crystal structure (R3‾ ${\bar{3}}$ c, Z=6, a=4.622 Å, c=42.576 Å) belongs to the Ni(ClO4)2‐type. The SO4 tetrahedra are rotated by 24°. The sense of rotation alternates between adjacent layers. This rotation is connected to a super structure with a doubled c‐axis and a disorder between the layers according to the sense of rotation. Ge(SO4)2 is one of the very rare examples of a sulphate of a tetravalent cation and is the representative with the smallest ionic radius. Lattice energy calculations confirm the electrostatic consistency. Vibrational spectra were recorded and show the typical features of GeO6 and SO4 units. [ABSTRACT FROM AUTHOR]

SrCo1-xMgxV2O7 (x = 0–0.09) dielectrics were prepared via the solid state route and the effect of Mg substitution on the microwave dielectric properties of the ceramics was systematically investigated. In addition to the relative density and microstructure, the dielectric polarizability, packing fraction, lattice energy and bond valence also play a crucial role in controlling the dielectric properties of the ceramics at microwave frequencies. A high lattice energy representing a high structural stability leads to a low dielectric loss in the specimen. Fluctuated variation of the τf was highly related to the bond valence of the samples. Specimens with x = 0.07 at 660°C revealed the highest Q × f of 23,000 GHz along with an εr of 13.2 and a τf of – 95 ppm/°C and it is chemically compatible with the Al electrode, suggesting that the dielectric is highly promising for ULTCC applications.

Some amino acid systems are known to exhibit solid solution and/or co-crystal behavior upon crystallization, which significantly affects their phase diagrams and complicates the design of their purification processes. Such behaviors are observed in the l-valine/l-leucine system. In this work, the formation and stability of a 3:1 co-crystal of the two amino acids (designated as V3L) is further investigated. To accomplish the formation, liquid-assisted grinding, slurry equilibration, and sublimation experiments were performed and analyzed via HPLC and PXRD. Additionally, periodic DFT calculations were used to calculate lattice energies and determine the thermodynamics of possible solid phases. Experimental results show a clear metastability of the investigated V3L co-crystals when compared to its stable solid solution. The calculations underline the metastability and the possible formation of continuous solid solutions between l-valine and l-leucine since lattice energy differences between pure amino acids and mixed compositions are negligible. This previously unknown phase behavior can be used to assess the influence of V3L on the amino acid purification process and provides a basis for investigating similar systems with small energy differences between pure and mixed compositions in future studies. In addition, it demonstrates the particular variability of solid phases and their relationships in such simple but biologically important amino acid systems.

Roseolumiflavin is a deep red microcrystalline derivative of isoalloxazine that exhibits a weak photophysical activity in the solid state. In aqueous as well as in acidic solution of formic or acetic acid, respectively, it tends to form solvates. Herein, we present a set of binary and ternary roseolumiflavin solvates including one hydrate and a solvate hydrate. The impact of the solvent on solvate formation along with an in-depth structural analysis was investigated. Calculations of the lattice energies provide insight into the phase stability of the evaluated systems showing an energetic benefit for all solvates with values up to −395.82 kJ/mol. The total interaction energies between molecules calculated via Crystal Explorer further identified cofacial π···π stacks to be the most strongly bonding fragments in the crystal lattices for all systems except the formic acid solvate, followed by remarkably weaker hydrogen-bonded arrangements. The energetic contributions of single intermolecular interactions within the fragments are evaluated by an atoms-in-molecules approach. It is shown that physicochemical properties, such as thermal stability, can be tuned depending on the incorporated solvent molecules despite a high decomposition temperature of the chromophore.

Testosterone (17β-hydroxyandrost-4-en-3-one) is the primary naturally occurring anabolic–androgenic steroid. The crystal structures of three short esterified forms of testosterone, including propionate, phenylpropionate, and isocaproate ester, were determined via single-crystal X-ray diffraction. Furthermore, all the samples were investigated using powder X-ray diffraction, and their structural features were described and evaluated in terms of crystal energies and Hirshfeld surfaces. They were also compared with the base form of testosterone (without ester) and the acetate ester. Moreover, from a pharmaceutical perspective, their solubility was evaluated and correlated with the length of the ester. [ABSTRACT FROM AUTHOR]

In this work, Cu-substituted MgAl2O4 ceramics were prepared via solid-state reaction. The crystal structure, cation distribution, and microwave dielectric properties of Mg1−xCuxAl2O4 ceramics were investigated. Cu2+ entered the MgAl2O4 lattice and formed a spinel structure. The substitution of Cu2+ ions for Mg2+ ions contributed to Al3+ ions preferential occupation of the octahedron and changed the degree of inversion. The quality factor (Qf) value, which is correlated with the degree of inversion, increased to a maximum value at x = 0.04 and then decreased. Ionic polarizability and relative density affected the dielectric constant (εr) value. The temperature coefficient of the resonant frequency (τf) value, which was dominated by the total bond energy, generally shifted to the positive direction. Satisfactory microwave dielectric properties were achieved in x = 0.04 and sintered at 1550 °C: εr = 8.28, Qf = 72,800 GHz, and τf = −59 ppm/°C. The Mg1−xCuxAl2O4 solid solution, possessing good performance, has potential for application in the field of modern telecommunication technology. [ABSTRACT FROM AUTHOR]

Advancing grid-scale energy storage technologies is crucial for realizing a fully renewable energy landscape, with non-aqueous redox flow batteries (NRFBs) presenting a promising solution. One of the current challenges in NRFBs stems from the low energy density of redox active materials, primarily due to their limited solubility in non-aqueous solvents. Herein, this study explores the solubility of vanadium(IV/V) bis-hydroxyiminodiacetate (VBH) crystals in acetonitrile, aiming to use them as anionic catholytes in NRFBs. We focused on enhancing VBH solubility by modifying the structure of the alkylammonium cation. Employing periodic density functional theory and a solvation model, we calculated the dissolution free energy ([[EQUATION]]), which includes sublimation ([[EQUATION]]) and solvation ([[EQUATION]]) energies. Our results indicate that neither elongating straight-chain alkyl groups beyond a tetrabutylammonium baseline nor introducing bulky substituents at the nitrogen center significantly enhances solubility. However, the introduction of carbon spacers combined with terminal bulky substituents markedly improves solubility by favorably altering both [[EQUATION]] and [[EQUATION]]. These findings underline the nuanced impact of cation structure on solubility and suggest a viable approach to optimize VBH-based anionic catholytes. This advancement promises to enhance NRFB efficiency and sustainability, marking a significant step forward in energy storage technology., (© 2024 Wiley‐VCH GmbH.)

MgTi1−x(Mn1/3Nb2/3)xO3 (x = 0–0.30) ceramics were prepared via the solid-state reaction method. The phase composition, microstructure, bond characteristics, and microwave dielectric properties of MgTi1−x(Mn1/3Nb2/3)xO3 (x = 0–0.30) were systematically investigated. The MgTi1−x(Mn1/3Nb2/3)xO3 ceramics presented an ilmenite type with an R-3 space group, and the secondary-phase MgTi2O5 only existed at x = 0 and 0.30. The introduction of (Mn1/3Nb2/3)4+ effectively suppressed the formation of the MgTi2O5 phase. The variation trend of the dielectric constant (εr) was the same as relative density. The quality factor (Qf) value was enhanced by the stable microstructure, which was caused via the lattice energy of Ti/(Mn1/3Nb2/3)-O bonds. And a high Qf value (353,000 GHz) was obtained for MgTi1−x(Mn1/3Nb2/3)xO3 (x = 0.04) ceramics sintered at 1250 °C. In addition, the introduction of Mn2+ ions with a larger ionic radius exacerbates the distortion of TiO6 octahedra, leading to significant fluctuations in the temperature coefficient of the resonance frequency (τf) value.

Two monoclinic (P21/c; Z′ = 1) polymorphs, α (from methanol) and β (from ethanol, n-propanol and iso-propanol), of a bioactive pyrazolo[3,4-d]pyrimidine derivative have been isolated and characterised by X-ray crystallography as well as by a range of computational chemistry techniques. The different conformations observed for the molecules in the crystals are due to the dictates of molecular packing as revealed by geometry-optimisation calculations. The crucial difference in the molecular packing pertains to the formation of phenylamino-N–H···N(pyrazolyl) hydrogen bonding within supramolecular chains with either helical (α-form; 21-screw symmetry) or zigzag (β-form; glide symmetry). As a consequence, the molecular packing is quite distinct in the polymorphs. Lattice energy calculations indicate the β-form is more stable by 11 kJ/mol than the α-form.

The present study systematically invesitgates the formation and microwave dielectric properties of novel AgMgVO 4 ceramics fabricated via the solid-state reaction method. The crystal structure of the ceramics is confirmed to be orthorhombic with a space Group of Pnma (62). A high relative density of 96.2% and an excellent combination of microwave dielectric properties with ε r of ~14.89, Q × f of ~19,400 GHz, and τ f of ~ − 2.71 ppm/°C can be achieved for the ceramic sintered at 630 °C. The dielectric constant is mainly influenced by the relative density (porosity) and dielectric polarizability. The Q × f is controlled by the microstructure, packing fraction, and lattice energy, which are also highly related to the unit-cell volume. A smaller unit-cell volume leads to a high Q × f. Variation of the τ f is strongly correlated to the bond valence of the specimen. Furthermore, the ceramic exhibits good chemical compatibility with aluminum electrodes and is demonstrated as a potent substrate for a band-pass filter with a center frequency of 3.5 GHz. These findings show a great promise for ultra-low temperature co-fired ceramic applications at high frequencies. [ABSTRACT FROM AUTHOR]

Molecular-scale modelling for predicting surface energies on a face-specific and whole particle basis is applied to all the crystallographically-independent surfaces of L-glutamic acid forms. The predicted data is found to be in good general agreement with measured surface energies using inverse gas chromatography and Washburn capillary rise techniques with the former revealing higher values compared to the prediction, perhaps consistent with the polar (zwitterionic) nature of this material. This fusion of experimental and computational data provides a high-fidelity definition of the face-by-face breakdown of the energetic anisotropy of the crystals. There is increasing industrial interest in defining the potential impact of whole particle properties on the performance of formulated drug product and their manufacturability especially as the community accelerates the molecule to medicine journey. The overall molecular modelling approach highlights its application in designing ingredients for optimising face-specific particle surface energies for product formulatability particularly in early phase process development. A route map from molecular and crystallographic structure to surface energy calculation with combined experimental workflow. [Display omitted] • A methodology fusing experimental and computational workflows for the investigation of crystal surface energy has been presented. • Molecular-scale (synthonic) modelling used to predict the surface energies of α and β forms of L-glutamic acid on a face-specific and whole particle basis. • Predicted surface energies are in good general agreement with measurements using IGC and Washburn capillary rise techniques. • Calculated surface energies have the same trend as those from experiments though they are higher than the experimental values, which are consistent with literature findings. • The overall molecular modelling approach demonstrates its application in designing crystal habit for optimising particle surface energies for product formulatability particularly in early phase process development. [ABSTRACT FROM AUTHOR]

How to search for a convenient method without a complicated calculation process to predict the physicochemical properties of inorganic crystals through a simple micro-parameter is a greatly important issue in the field of materials science. Herein, this paper presents a new and facile technique for the comprehensive estimation of lattice energy (U), bulk modulus (B), chemical hardness (ƞ), and electronic polarizability (α), just by using a simple mathematic fitting formula with a few structure parameters, such as the systems of rock salt crystals (group I–VII, II–VI) and tetrahedral coordinated crystals (group II–VI, III–V). For the typical binary ANB8-N crystal systems, our present conclusions suggest that a good quantitative correlation between U, B, ƞ, α and chemical bond length (d) is observed, the normal mathematical expression is P = a·db (P represents these physicochemical parameters), constants a and b depend on the type of crystals, and the relevant squares of the correlation coefficient (R2) are larger than 0.9. The results indicate that lattice energy, bulk modulus, and chemical hardness decrease with increases in chemical bond length, but electronic polarizability increases with an increase in chemical bond length. Meanwhile, the new data on the lattice energy, bulk modulus, chemical hardness, and electronic polarizability values of binary ANB8-N crystal systems considered in the present study are calculated via the obtained curve fitting equations without any complex calculation process. We find that there is a very good linear trend in our calculated results along with the values reported in the literature. The present study will be important in solid-state chemistry, which may give researchers useful guidance in searching for relevant data for predicting the properties of new materials or synthetic routes based on a simple mathematic empirical model.

Testosterone (17β-Hydroxyandrost-4-en-3-one) is the primary male anabolic-androgenic steroid. The crystal structures of two medium and two long esterified forms of testosterone, including enanthate, cypionate, decanoate and undecanoate, were determined by X-ray single crystal diffraction. The samples were also characterized by powder X-ray diffraction, FT-IR spectroscopy and thermal analysis (DTA, TG). Crystal packings and supramolecular features were described. The analysis of structural features was accomplished by computational methods in terms of the type of intermolecular interactions, crystal energies and Hirshfeld surfaces analysis. From a pharmaceutical point of view, the solubility of compounds was investigated.

The crystal structures and thermal characteristics of two polymorphs of methylethanolammonium 2-chloro-4-nitrobenzoate were investigated by a combined experimental and computational approach. The main attention was paid to the synthesis of polymorphs, structural characterization associated with computational studies on the nature of intermolecular interactions, and thermodynamic stability relationship between the polymorphs and thermal decomposition kinetics. Analysis of the polymorphs structure revealed distinct crystal packing arrangements and different numbers of independent molecules pairs in the asymmetric crystal unit. Depending on the conformation of cations, polymorphs α and β exhibit the formation of different charge-assisted and normal hydrogen bonds, while in β, non-covalent interactions of halogens are also manifested. The calculated values of the lattice energies indicated that α has a more stable lattice than β at high temperatures. The thermodynamic stability relationship between the polymorphs pair is monotropic and is determined by measuring melting points and heats of fusion. The kinetics of thermal decomposition processes has been comparatively studied by two different kinetic methods. The results showed higher activation energies for α compared to β. According to the modified nonparametric kinetic method, the decomposition mechanism revealed two distinct stages in both polymorphs, indicating one predominant chemical degradation process followed by a physical transformation process. [ABSTRACT FROM AUTHOR]

It is worth it to explore the extraction performance for vanadium by the imidazole ionic liquids. The extraction of vanadium (V) was studied using [Omim]Cl, [Omim]Br, and [Omim][BF4] as extractants. The effects of various diluents, equilibrium time, extraction temperature, and anion species were investigated. The structure-activity relationship of vanadium and ILs was discussed by calculating the lattice energy of ILs based on the Glasser theory and the volume of anions. The results show that n-pentanol is the optimum diluent. Under the extraction conditions of an equilibrium time of 60 s and extraction temperature of 25 °C, the extraction rates of V (V) by [Omim]Cl, [Omim]Br, and [Omim][BF4] reached 97.93%, 96.59%, and 87.01%, respectively. Furthermore, based on the Glasser theory, the lattice energy of ionic liquids decreased in the order [Omim]Cl > [Omim]Br > [Omim]BF4. The volume of the anions increased in the order Cl− < Br− < BF4− < HVO42−. The extraction rate of V (V) depended on the size of the anions and the strength of the interaction between the anion and imidazolium cation. The results of counterevidence experiments verified the larger the anion volume, the easier it is to combine with cation in the organic phase, and the lattice energy of extracted compound is lower. The statistical analysis showed that the effect of the equilibrium time and temperature were not significant in the model, and the anions species showed a significant effect on the extraction efficiency of V (V). [ABSTRACT FROM AUTHOR]

Synthesis, X-ray structure, molecular docking, lattice energy and Hirshfeld surface analysis of (E)-2-methoxy-5-(((6-methoxypyridin-3yl)imino)methyl)phenol (MMPIMP) is presented in this paper. The compound crystallizes in the monoclinic space group P21/c with unit cell parameters: a = 5.6149 (2), b = 14.5520 (5), c = 29.9813 (8) Å, β = 94.795 (3) and Z = 8. The asymmetric unit contains two crystallographically independent molecules (A and B) and the structure was solved by direct methods using single-crystal X-ray diffraction data and refined by full-matrix least-squares procedure to a final value of R = 0.050 and wR2 = 0.1231 for 3536 observed reflections. The molecular packing in the unit cell is stabilized via O – H... N and C – H... O intermolecular hydrogen bonds. In the crystal packing, pairs of intermolecular hydrogen bonds of the type O–H...N links the molecules into dimers, forming R 2 2 (20) ring motif. To understand the nature and strength of intermolecular interaction in terms of its energy and their quantitative contributions toward the molecular packing, lattice energy analysis was carried out by using PIXEL software. Molecular docking studies were executed to realize the inhibitory activity of the compound MMPIMP against DprE1 (PDB code: 4KW5). The analysis of the Hirshfeld surface and its associated two dimension fingerprint plots has been carried out to examine the intermolecular contacts in the crystal structure. [ABSTRACT FROM AUTHOR]

Although the non-covalent interactions such as hydrogen bonds and Van der Waals bonds are considered as weak but have a significant impact on the characteristics of the molecule in solution and the crystalline phase. The nature and strength of such intermolecular interactions result in various physicochemical and biological properties in crystal structures. In the present study, a quantitative analysis of intermolecular interaction in the crystal packing of some bromine substituted coumarin derivatives has been undertaken for lattice energy and intermolecular interaction energies analyses using a computational approach. The analysis shows that the energy contribution of halogen bonds such as C-Br...O and C-Br...π is quite significant in the crystal structures of bromine substituted coumarins. Besides, the C-H...O, C-H...Br and π...π interactions are also found to have a profound effect on the molecular packing of these structures. Molecular interactions with reference to the packing mechanism in each molecule are studied in detail. It is expected that empirical analysis of molecular energy interactions will help in understanding the role of various structural motifs in crystal packing. [ABSTRACT FROM AUTHOR]

A total of 14 compounds, one unsubstituted and 13 halogen‐substituted phosphoramidates, have been synthesized from unsubstituted and halogenated (fluoro‐, difluoro‐, chloro‐, bromo‐, iodo‐substituted) aniline and diphenyl phosphoryl chloride to investigate their molecular assembly in solid‐state structures. Amongst them, six groups were formed based on similarities in unit‐cell dimensions, space group and molecular assembly of the crystal. The analysis reveals that all the crystal structures contain robust N—H...O hydrogen bonds which are the primary building blocks with ancillary interactions such as C—H...O, C—H...π, C—H...F/Cl/Br/I, F...F, F...π, I...π, Br...π, I...O and Br...O. The role of short and directional C—H...O and C—H...π interactions providing significant stabilization to the densely packed crystalline arrangement is discussed. The contribution of these interactions in stabilizing the crystalline assembly was deduced via computing total interaction energy between dimers and the overall lattice energies using the computer programs Crystal Explorer 17.5 and PIXELC, respectively. Additionally, the occurrence of 3D isostructurality in phosphoradimates and their halogenated analogs was investigated using the XPac program. A comparison of the magnitudes of the torsion angles in the compounds substantiates the role of conformational flexibility in the solid state. [ABSTRACT FROM AUTHOR]

SrCo1-xMgxV2O7 (x = 0–0.09) dielectrics were prepared via the solid state route and the effect of Mg substitution on the microwave dielectric properties of the ceramics was systematically investigated. In addition to the relative density and microstructure, the dielectric polarizability, packing fraction, lattice energy and bond valence also play a crucial role in controlling the dielectric properties of the ceramics at microwave frequencies. A high lattice energy representing a high structural stability leads to a low dielectric loss in the specimen. Fluctuated variation of the τf was highly related to the bond valence of the samples. Specimens with x = 0.07 at 660°C revealed the highest Q × f of 23,000 GHz along with an εr of 13.2 and a τf of – 95 ppm/°C and it is chemically compatible with the Al electrode, suggesting that the dielectric is highly promising for ULTCC applications. [ABSTRACT FROM AUTHOR]

A seventh blind test of crystal structure prediction has been organized by the Cambridge Crystallographic Data Centre. The results are presented in two parts, with this second part focusing on methods for ranking crystal structures in order of stability. The exercise involved standardized sets of structures seeded from a range of structure generation methods. Participants from 22 groups applied several periodic DFT-D methods, machine learned potentials, force fields derived from empirical data or quantum chemical calculations, and various combinations of the above. In addition, one non-energy-based scoring function was used. Results showed that periodic DFT-D methods overall agreed with experimental data within expected error margins, while one machine learned model, applying system-specific AIMnet potentials, agreed with experiment in many cases demonstrating promise as an efficient alternative to DFT-based methods. For target XXXII, a consensus was reached across periodic DFT methods, with consistently high predicted energies of experimental forms relative to the global minimum (above 4 kJ mol -1 at both low and ambient temperatures) suggesting a more stable polymorph is likely not yet observed. The calculation of free energies at ambient temperatures offered improvement of predictions only in some cases (for targets XXVII and XXXI). Several avenues for future research have been suggested, highlighting the need for greater efficiency considering the vast amounts of resources utilized in many cases., (open access.)

A seventh blind test of crystal structure prediction was organized by the Cambridge Crystallographic Data Centre featuring seven target systems of varying complexity: a silicon and iodine-containing molecule, a copper coordination complex, a near-rigid molecule, a cocrystal, a polymorphic small agrochemical, a highly flexible polymorphic drug candidate, and a polymorphic morpholine salt. In this first of two parts focusing on structure generation methods, many crystal structure prediction (CSP) methods performed well for the small but flexible agrochemical compound, successfully reproducing the experimentally observed crystal structures, while few groups were successful for the systems of higher complexity. A powder X-ray diffraction (PXRD) assisted exercise demonstrated the use of CSP in successfully determining a crystal structure from a low-quality PXRD pattern. The use of CSP in the prediction of likely cocrystal stoichiometry was also explored, demonstrating multiple possible approaches. Crystallographic disorder emerged as an important theme throughout the test as both a challenge for analysis and a major achievement where two groups blindly predicted the existence of disorder for the first time. Additionally, large-scale comparisons of the sets of predicted crystal structures also showed that some methods yield sets that largely contain the same crystal structures., (open access.)

Granulation of racemic ibuprofen (±IBP) and α-lactose monohydrate (ALM) at a slightly lower (±IBP) melting point is an efficient method of binding the active pharmaceutical ingredients (API) and excipient in a binderless condition. However, the co-crystals may be formed from recrystallization of ±IBP on ALM. The objective of this study is to evaluate the tendency of co-crystal formation of granules (3:7 w/w ratio of ±IBP:ALM) by melt granulation process. Second, investigate the recovery of crystals from polyethylene glycol (PEG) 300 solutions containing ±IBP-ALM mixtures. Characterizations of the samples were performed using Fourier Transform Infrared (FTIR) spectroscopy, Differential Scanning Calorimetry (DSC) and Powder X-Ray Diffraction (PXRD) system of the ±IBP-ALM granules produced from melt crystallization and harvested crystals from PEG 300 solution which is produced using slow evaporation crystallization. Crystal analysis of solution containing ±IBP-ALM mixtures revealed that the crystals formed were not co-crystals. Molecular interactions assessment through binding prediction between ±IBP and ALM terminating surfaces was conducted using molecular modelling technique. The result showed that the favorable binding sites of ±IBP molecules were on the surfaces of (0-20), (1-10), (001) and (011) ALM crystals. Successful binding prediction by the attachment energy method has proven that the co-crystal formation between these molecules is theoretically possible.

The two isomers 2′-(4-nitrobenzoyloxy)acetophenone (systematic name: 2-acetylphenyl 4-nitrobenzoate) (I) and 2′-(2-nitrobenzoyloxy)acetophenone (systematic name: 2-acetylphenyl 2-nitrobenzoate) (II), both C15H11NO5, with para and ortho positions of the nitro substituent have been crystallized and studied. It is evident that the variation in the position of the nitro group causes a significant difference in the molecular conformations: the dihedral angle between the aromatic fragments in the molecule of I is 84.80 (4)°, while that in the molecule of II is 6.12 (7)°. Diffraction analysis revealed the presence of a small amount of water in the crystal of I. DFT calculations of the molecular energy demonstrate that the ortho substituent causes a higher energy for isomer II, while crystal lattice energy calculations show that the values are almost equal for two isomers.

Single crystals of two polymorphic forms of 4′-methyl-2,4-dinitrodiphenylamine were obtained by crystallization and characterized by X-ray diffraction analysis. One of the forms is non-centrosymmetric (space group P21212), while the second is centrosymmetric (space group P¯1) and contains two crystallographically independent molecules in the asymmetric unit. In both forms, the same supramolecular synthon, a dimer linked by bonding N-H···O, O···O, and C-H···O interactions were found. Despite nearly the same connectivity of the bonding interactions, the conformation of the supramolecular synthon is different, including its unavoidably different symmetry in two polymorphs. The comparison of the crystal packing of the orthorhombic polymorph with that of the related 2,4-dinitrodiphenylamine (space group P21/n) shows the quasi-isostructurality of the fragments, infinite π-stacks joined by weak non-directional intermolecular interactions. However, the fragments are linked by the supramolecular synthons via either a two-fold axis or an inversion center, which lead to only the partial isostructurality of the crystals.

The microwave dielectric properties of spinel-structured Li(Mg 0.5 Ti 0.5) x Ga 5− x O 8 (0 ≤ x ≤ 1) ceramics were researched together with their microstructures. The X-ray diffraction and Raman spectroscopic revealed that an ordered spinel structure in 1: 3 B-site ordering with space group P 4 3 32 was formed in the composition range of 0 = x ≤ 0.25, and a disordered spinel with space group Fd -3 m was formed in 0.5 = x ≤ 1. All the ceramics were compact with uniform grain, clear grain boundaries and high relative density (ρ relative ≥ 95 %). With the substitution of [Mg 0.5 Ti 0.5 ]3+ for Ga3+ increased, the dielectric constant (ε r) increased from 10.48 to 11.28, which was related to the increased molar ionic polarizability (α theo / V m) and B-site bond ionicity. The temperature coefficient of the resonant frequency (τ f) slightly increased from −66.27 ppm/°C to −61.45 ppm/°C, due to the decrease of B-site bond valence. The Q × f value firstly decreased from 125,400 GHz to 50,381 GHz and then increased to 85,360 GHz, which was affected by the intrinsic loss analyzed by lattice energy. The optimal microwave dielectric properties were obtained for LiMg 0.5 Ti 0.5 Ga 4 O 8 ceramic (x = 1) sintered at 1260 °C with ε r = 11.28, Q × f = 85,360 GHz and τ f = −61.45 ppm/°C. [ABSTRACT FROM AUTHOR]

Many discussions of the intermolecular interactions in crystal structures concentrate almost exclusively on an analysis of hydrogen bonding. A simple analysis of atom–atom distances is all that is required to detect and analyse hydrogen bonding. However, for typical small‐molecule organic crystal structures, hydrogen‐bonding interactions are often responsible for less than 50% of the crystal lattice energy. It is more difficult to analyse intermolecular interactions based on van der Waals interactions. The Pixel program can calculate and partition intermolecular energies into Coulombic, polarization, dispersion and repulsion energies, and help put crystal structure discussions onto a rational basis. This Windows PC implementation of Pixel within the Oscail package requires minimal setup and can automatically use GAUSSIAN or Orca for the calculation of electron density. [ABSTRACT FROM AUTHOR]

We consider interaction energies E f [ L ] between a point O ∈ R d , d ≥ 2 , and a lattice L containing O, where the interaction potential f is assumed to be radially symmetric and decaying sufficiently fast at infinity. We investigate the conservation of optimality results for E f when integer sublattices kL are removed (periodic arrays of vacancies) or substituted (periodic arrays of substitutional defects). We consider separately the non-shifted ( O ∈ k L ) and shifted ( O ∉ k L ) cases and we derive several general conditions ensuring the (non-)optimality of a universal optimizer among lattices for the new energy including defects. Furthermore, in the case of inverse power laws and Lennard-Jones-type potentials, we give necessary and sufficient conditions on non-shifted periodic vacancies or substitutional defects for the conservation of minimality results at fixed density. Different examples of applications are presented, including optimality results for the Kagome lattice and energy comparisons of certain ionic-like structures. [ABSTRACT FROM AUTHOR]

Testosterone (17β-hydroxyandrost-4-en-3-one) is the primary naturally occurring anabolic–androgenic steroid. The crystal structures of three short esterified forms of testosterone, including propionate, phenylpropionate, and isocaproate ester, were determined via single-crystal X-ray diffraction. Furthermore, all the samples were investigated using powder X-ray diffraction, and their structural features were described and evaluated in terms of crystal energies and Hirshfeld surfaces. They were also compared with the base form of testosterone (without ester) and the acetate ester. Moreover, from a pharmaceutical perspective, their solubility was evaluated and correlated with the length of the ester.