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A new polymorph of 1,3-diacetylpyrene has been obtained from its melt and thoroughly characterized using single-crystal X-ray diffraction, steady-state UV-Vis spectroscopy and periodic density functional theory calculations. Experimental studies covered the temperature range from 90 to 390 K and the pressure range from atmospheric to 4.08 GPa. Optimal sample placement in a diamond anvil cell according to our previously presented methodology ensured over 80% data coverage up to 0.8 Å for a monoclinic sample. Unrestrained Hirshfeld atom refinement of the high-pressure crystal structures was successful and anharmonic behavior of carbonyl oxygen atoms was observed. Unlike the previously characterized polymorph, the structure of 2°AP-β is based on infinite π-stacks of antiparallel 2°AP molecules. 2°AP-β displays piezochromism and piezofluorochromism which are directly related to the variation in interplanar distances within the π-stacking. The importance of weak intermolecular interactions is reflected in the substantial negative thermal expansion coefficient of -55.8 (57) MK-1 in the direction of C-H...O interactions.

A new polymorph of 1,3-diacetylpyrene has been obtained from its melt and thoroughly characterized using single-crystal X-ray diffraction, steady-state UV–Vis spectroscopy and periodic density functional theory calculations. Experimental studies covered the temperature range from 90 to 390 K and the pressure range from atmospheric to 4.08 GPa. Optimal sample placement in a diamond anvil cell according to our previously presented methodology ensured over 80% data coverage up to 0.8 Å for a monoclinic sample. Unrestrained Hirshfeld atom refinement of the high-pressure crystal structures was successful and anharmonic behavior of carbonyl oxygen atoms was observed. Unlike the previously characterized polymorph, the structure of 2°AP-β is based on infinite π-stacks of antiparallel 2°AP molecules. 2°AP-β displays piezochromism and piezofluorochromism which are directly related to the variation in interplanar distances within the π-stacking. The importance of weak intermolecular interactions is reflected in the substantial negative thermal expansion coefficient of −55.8 (57) MK−1 in the direction of C—H...O interactions.

Hydrazonylsulfones such as Bt-NHNHSO2R and their iminotautomers have been studied as optical materials and for their biological potential. In this work, a structural study has been carried out on N-(1,3-benzothiazol-2-yl)-4-(halogenobenzenesulfonyl)-hydrazides (1: X = F, Cl, Br). For (1: X = F), single-crystal X-ray diffraction, Hirshfeld surface analysis, and PIXEL calculations were conducted, while in (1: X = Cl) and (1: X = Br), only single-crystal X-ray diffraction studies were successfully conducted due to the disordering of the solvent. Each compound crystallises with two independent but similar amino tautomers in the asymmetric units: compound (1: X = F) crystallises in the monoclinic P21/c, and the isostructural pair (X: 1 = Cl and Br) crystallises in the tetragonal P-421c space group. In the most stable motif of the supramolecular arrangement, the molecules of the asymmetric unit are connected by classical N–H(hydrazinyl)···N(thiazoyl) hydrogen bonds and several face-to-face, offset π···π interactions. This motif has a very powerful influence on the crystal structure due to its direct links with the other weaker motifs. Other significant intermolecular interactions found in the structure include N–H(hydrazonyl)···O(sulfonate) bonds. Analogous intermolecular interactions were found in similar compounds, leading to the conclusion that those interactions are the most important instabilizing the solid state of hydrazonylsulfones. [ABSTRACT FROM AUTHOR]

From its conception, X-ray crystallography has provided a unique understanding of the structure, bonding and electronic state of materials, which, in turn, unlocks a means of examining the properties and function of crystalline systems. Using state-of-the-art single-crystal X-ray diffraction, along with UV–Vis spectroscopy and DFT calculations, Zwolenik et al. [(2024). IUCrJ, 11, 519–527] have provided a comprehensive study of the structure–optical property relationship of 1,3-diacetylpyrene with methodologies that are increasingly accessible to non-specialist laboratories.

Hydrazonylsulfones such as Bt-NHNHSO2R and their iminotautomers have been studied as optical materials and for their biological potential. In this work, a structural study has been carried out on N-(1,3-benzothiazol-2-yl)-4-(halogenobenzenesulfonyl)-hydrazides (1: X = F, Cl, Br). For (1: X = F), single-crystal X-ray diffraction, Hirshfeld surface analysis, and PIXEL calculations were conducted, while in (1: X = Cl) and (1: X = Br), only single-crystal X-ray diffraction studies were successfully conducted due to the disordering of the solvent. Each compound crystallises with two independent but similar amino tautomers in the asymmetric units: compound (1: X = F) crystallises in the monoclinic P21/c, and the isostructural pair (X: 1 = Cl and Br) crystallises in the tetragonal P-421c space group. In the most stable motif of the supramolecular arrangement, the molecules of the asymmetric unit are connected by classical N–H(hydrazinyl)···N(thiazoyl) hydrogen bonds and several face-to-face, offset π···π interactions. This motif has a very powerful influence on the crystal structure due to its direct links with the other weaker motifs. Other significant intermolecular interactions found in the structure include N–H(hydrazonyl)···O(sulfonate) bonds. Analogous intermolecular interactions were found in similar compounds, leading to the conclusion that those interactions are the most important instabilizing the solid state of hydrazonylsulfones.

From its conception, X-ray crystallography has provided a unique understanding of the structure, bonding and electronic state of materials, which, in turn, unlocks a means of examining the properties and function of crystalline systems. Using state-of-the-art single-crystal X-ray diffraction, along with UV-Vis spectroscopy and DFT calculations, Zwolenik et al. [(2024). IUCrJ, 11, 519-527] have provided a comprehensive study of the structure-optical property relationship of 1,3-diacetylpyrene with methodologies that are increasingly accessible to non-specialist laboratories., (open access.)

We prove two geometric lemmas for 𝒮N−1-valued functions that allow to modify sequences of lattice spin functions on a small percentage of nodes during a discrete-to-continuum process so as to have a fixed average. This is used to simplify known formulas for the homogenization of spin systems. [ABSTRACT FROM AUTHOR]

We study the minimality properties of a new type of "soft" theta functions. For a lattice L ⊂ R d , an L-periodic distribution of mass μ L , and another mass ν z centered at z ∈ R d , we define, for all scaling parameters α > 0 , the translated lattice theta function θ μ L + ν z (α) as the Gaussian interaction energy between ν z and μ L . We show that any strict local or global minimality result that is true in the point case μ = ν = δ 0 also holds for L ↦ θ μ L + ν 0 (α) and z ↦ θ μ L + ν z (α) when the measures are radially symmetric with respect to the points of L ∪ { z } and sufficiently rescaled around them (i.e., at a low scale). The minimality at all scales is also proved when the radially symmetric measures are generated by a completely monotone kernel. The method is based on a generalized Jacobi transformation formula, some standard integral representations for lattice energies, and an approximation argument. Furthermore, for the honeycomb lattice H , the center of any primitive honeycomb is shown to minimize z ↦ θ μ H + ν z (α) , and many applications are stated for other particular physically relevant lattices including the triangular, square, cubic, orthorhombic, body-centered-cubic, and face-centered-cubic lattices. [ABSTRACT FROM AUTHOR]

We investigate the minimization of the energy per point E f among d-dimensional Bravais lattices, depending on the choice of pairwise potential equal to a radially symmetric function f (| x | 2) . We formulate criteria for minimality and non-minimality of some lattices for E f at fixed scale based on the sign of the inverse Laplace transform of f when f is a superposition of exponentials, beyond the class of completely monotone functions. We also construct a family of non-completely monotone functions having the triangular lattice as the unique minimizer of E f at any scale. For Lennard-Jones type potentials, we reduce the minimization problem among all Bravais lattices to a minimization over the smaller space of unit-density lattices and we establish a link to the maximum kissing problem. New numerical evidence for the optimality of particular lattices for all the exponents are also given. We finally design one-well potentials f such that the square lattice has lower energy E f than the triangular one. Many open questions are also presented. [ABSTRACT FROM AUTHOR]

This manuscript reports the improved synthesis of the α,α,α,α isomer of tetra-p-iodophenyl tetra-methyl calix[4]pyrrole and the X-ray characterization of two solvate polymorphs. In the solid state, the calix[4]pyrrole receptor adopts the cone conformation, including one acetonitrile molecule in its aromatic cavity by establishing four convergent hydrogen bonds between its nitrogen atom and the four pyrrole NHs of the former. The inclusion complexes pack into rods, displaying a unidirectional orientation. In turn, the rods form flat 2D-layers by alternating the orientation of their p-iodo substituents. The 2D layers stack on top of another, resulting in a head-to-head and tail-to-tail orientation of the complexes or their exclusive arrangement in a head-to-tail geometry. The dissimilar stacking of the layers yields two solvate polymorphs that are simultaneously present in the structures of the single crystals. The ratio of the two polymorph phases is regulated by the amount of acetonitrile added to the chloroform solutions from which the crystals grow. Halogen bonding interactions are highly relevant in the crystal lattices of the two polymorphs. We analyzed and characterized these interactions by means of density functional theory (DFT) calculations and several computational tools. Remarkably, single crystals of a solvate containing two acetonitrile molecules per calix[4]pyrrole were obtained from pure acetonitrile solution.

The in situ crystallization is the most suitable way to obtain a crystal of a low-melting-point compound to determine its structure via X-Ray diffraction. Herein, the intermolecular interactions and some crystal properties of low-melting-point organoelement compounds (lattice energies, melting points, etc.) are discussed. The discussed structures were divided into two groups: organoelement compounds of groups 13−16 and organofluorine compounds with other halogen atoms (Cl, Br, I). The most of intermolecular interactions in the first group are represented by weak hydrogen bonds and H···H interactions. The crystal packing of the second group of compounds is stabilized by various interactions between halogen atoms in conjunction with hydrogen bonding and stacking interactions. The data on intermolecular interactions from the analysis of crystal packing allowed us to obtain correlations between lattice energies and Hirshfeld molecular surface areas, molecular volumes, and melting points.

CE-B3LYP model energies are used to investigate intermolecular interactions in crystals of the relatively weakly bound cyclic ethers, as well as a number of substituted epoxides that have been the focus of high-quality experimental electron density studies. This approach readily provides a complete picture of all intermolecular interactions in these molecular crystals, and CE-B3LYP lattice energies for the unsubstituted cyclic ethers are in excellent agreement with available thermodynamic data. When compared with the outcomes of multipole modelling of X-ray diffraction data, these results suggest that experimental interaction energies are typically underestimated and, contrarily, experimental lattice energies are typically overestimated. These observations deserve careful investigation. [ABSTRACT FROM AUTHOR]

The sixth blind test of organic crystal structure prediction (CSP) methods has been held, with five target systems: a small nearly rigid molecule, a polymorphic former drug candidate, a chloride salt hydrate, a co-crystal and a bulky flexible molecule. This blind test has seen substantial growth in the number of participants, with the broad range of prediction methods giving a unique insight into the state of the art in the field. Significant progress has been seen in treating flexible molecules, usage of hierarchical approaches to ranking structures, the application of density-functional approximations, and the establishment of new workflows and `best practices' for performing CSP calculations. All of the targets, apart from a single potentially disordered Z′ = 2 polymorph of the drug candidate, were predicted by at least one submission. Despite many remaining challenges, it is clear that CSP methods are becoming more applicable to a wider range of real systems, including salts, hydrates and larger flexible molecules. The results also highlight the potential for CSP calculations to complement and augment experimental studies of organic solid forms. [ABSTRACT FROM AUTHOR]

Lithium chloro- and bromoaluminates were prepared, fully characterized, and investigated as conducting salts for battery applications. In addition, thermodynamic investigations of their lattice enthalpies and other quantities were carried out. The Li[AlX4] salts also show very high conductivities in solvents of very low polarity, which makes them suitable candidates for conducting salts and battery systems working with voltages below ca. 3.5 V (X = Br) or ca. 4.4 V (X = Cl), such as lithium-sulfur batteries (LSBs). In particular, the bromoaluminates, with their Pearson-soft character, which prevents ion-pair formation with the Pearson-hard lithium ion, are promising for this purpose. An interesting alternative solvent for LSBs might be o-difluorobenzene, in which Li[AlBr4] shows very high solubility and conductivity. The carbonate solvents typically used for LIBs are not suitable for the bromoaluminates, and Li[AlCl4] also shows corrosive behavior towards aluminum at potentials higher than 2.5 V. This can be prevented by, for example, addition of Li[PF6]. [ABSTRACT FROM AUTHOR]

Abstract: Lattice energies ΔL H θ of lanthanide gallium garnets Ln3Ga5O12 (Ln=Nd–Lu) have been determined from the Born–Haber thermochemical cycle and compared with those previously obtained by atomistic simulations in the Born model or calculated by an empirical equation. The Born–Haber cycle yields the lowest values among the three methods. Molar polarizations P m of Ln3Ga5O12 have been calculated by the Debye equation. It has been found that the partial derivative (∂ΔL H θ/∂P m) corresponds by magnitude to the shear moduli of these crystals. [Copyright &y& Elsevier]

We study the asymptotic behavior of dilute spin lattice energies by exhibiting a continuous interfacial limit energy computed using the notion of Γ-convergence and techniques mixing Geometric Measure Theory and Percolation while scaling to zero the lattice spacing. The limit is not trivial above a percolation threshold. Since the lattice energies are not equi-coercive, a suitable notion of limit magnetization must be defined, which can be characterized by two phases separated by an interface. The macroscopic surface tension at this interface is characterized through a first-passage percolation formula, which highlights interesting connections between variational problems and percolation issues. A companion result on the asymptotic description on energies defined on paths in a dilute environment is also given. [ABSTRACT FROM AUTHOR]

Abstract: Lattice energies ΔLHΘ of the entire series of lanthanide aluminum perovskites LnAlO3, Ln=Ce–Lu, have been determined for the first time by means of the Born–Haber cycle. The results have been compared for LnAlO3 obtained by other methods, with cubic lanthanide sesquioxides (C-Ln2O3) and lanthanide aluminum garnets (Ln3Al5O12). Polarizability volumes α I of LnAlO3 have been estimated by the Clausius–Mossotti equation. It has been found that the partial derivative (∂ΔLHΘ/∂α I ) T corresponds by magnitude to an upper limit of elastic moduli of the same crystals. [Copyright &y& Elsevier]

The melting temperatures and absolute values of melting enthalpies of lanthanide trichlorides decrease from LaCl3to TbCl3and then increase to LuCl3. The preceding decrease cannot be explained by the lattice energies of the trichlorides, since they increase continuously from the lanthanum to the lutetium compounds. However, it may be attributed to the structural features of the liquid state. The liquids near the melting points consist of clusters of complex units, which become larger with decreasing radii of the metal ions. To prove this assumption additional quantitative investigations are necessary. [ABSTRACT FROM AUTHOR]

Abstract: The standard (p°=0.1MPa) molar enthalpies of formation in the crystalline state of the alkaline metal acetates CH3COOM (M=Li, Na, K, Rb, Cs), at T =298.15K, were determined by reaction-solution calorimetry as: kJmol−1, kJmol−1, kJmol−1, kJmol−1, kJmol−1. These results, taken together with the enthalpies of formation of the haloacetates XCH2COOM (M=Li, Na; X=Cl, Br, I) and chloropropionates ClCH(CH3)COOM (M=Li, Na) re-evaluated from literature data were used to derive a consistent set of lattice energies, and discuss some general trends of the structure–energetics relationship for the CH3COOM, XCH2COOM, and ClCH(CH3)COOM compounds, based on the Kapustinskii approximation. It was found that the lattice energies of the haloacetates are essentially independent of the halogen and ca. 17–25kJmol−1 smaller than those of the corresponding acetates. In addition, no significant difference between the lattice enthalpy values of the haloacetates and chloropropionates was observed. Finally, linear correlations of very similar slope were obtained by plotting the Mstances derived from the Kapustinskii equation against the published experimental Mstances for alkaline metal acetates and alkoxides. The analysis of these relations suggests that the metal–oxygen bond distances for the lithium, potassium, and rubidium acetates, whose molecular structures in the solid state have not been determined, can be estimated as 214, 288, and 304pm, respectively. [Copyright &y& Elsevier]

The thermodynamic systematics of the formation and phase changes of a range of materials which form ionic liquids is examined, based upon experimental values of densities and calorimetric quantities. Certain results are shown to be consistent across groups of these materials, namely: the lattice potential energies decrease with increasing alkyl chain length; the molecular volumes and ‘total phase change’ entropies (from crystal through liquid crystalline phases to melt) increase linearly with alkyl group chain length for pyridinium cations. However, the total phase change transition entropies for the two 1-alkyl-3-methylimidazolium cation systems examined are anomalous, having dome-shaped graphs with a dip in value around C14. [Copyright &y& Elsevier]

[Display omitted] • We propose an antipodal conjecture to prepare K + K CO 8 - , which is defined as antipodal salt of alkalide K C 222 + K -. • Theoretical results show that K element in K CO 8 - shows transition metal properties. • This provides the possibility for the synthesis of K + K CO 8 -. Here we propose an antipodal conjecture, which is based on the synthetic scheme of alkalide K C 222 + K - , to prepare K + K CO 8 -. By introducing the concept of antipodal salts of alkalides, K + K CO 8 - is defined as antipodal salt of K C 222 + K -. As Group 1 elements of the Periodic Table, the alkali metal K is conventionally considered to form chemical bonding through its 4s and 4p valence orbitals. Our theoretical results show that the 3d orbitals of K element in K CO 8 - participate in chemical bonding of K CO 8 -. This makes the alkali metal K shows typical transition metal chemical properties, which also provides the possibility for the synthesis of K + K CO 8 -. Based on the Born-Haber thermodynamic cycle, the upper-limit stable temperature of K + K CO 8 - is estimated to be 24.426 K. Our theoretical results indicate that antipodal salts of alkalides will be a new family of compounds with good synthetic prospects. [ABSTRACT FROM AUTHOR]

Abstract: Madelung (U M ) and experimental lattice (U P ) energies have been determined for the series of lanthanide monosulphides (LnS, Ln=Ce—Lu, excluding Pm). Comparative crystal-field (CF) analysis has been performed for the same series in the point-charge model with inclusion of the ground 4f n and the excited 4f n–15d configurations. It has been found that the variations of both U M /U P and the CF parameters for the 4f n–15d configuration across the lanthanide series exhibit minima for the magnetic semiconductors SmS, EuS, and YbS. [ABSTRACT FROM AUTHOR]

This manuscript reports the improved synthesis of the α,α,α,α isomer of tetra-p-iodophenyl tetra-methyl calix[4]pyrrole and the X-ray characterization of two solvate polymorphs. In the solid state, the calix[4]pyrrole receptor adopts the cone conformation, including one acetonitrile molecule in its aromatic cavity by establishing four convergent hydrogen bonds between its nitrogen atom and the four pyrrole NHs of the former. The inclusion complexes pack into rods, displaying a unidirectional orientation. In turn, the rods form flat 2D-layers by alternating the orientation of their p-iodo substituents. The 2D layers stack on top of another, resulting in a head-to-head and tail-to-tail orientation of the complexes or their exclusive arrangement in a head-to-tail geometry. The dissimilar stacking of the layers yields two solvate polymorphs that are simultaneously present in the structures of the single crystals. The ratio of the two polymorph phases is regulated by the amount of acetonitrile added to the chloroform solutions from which the crystals grow. Halogen bonding interactions are highly relevant in the crystal lattices of the two polymorphs. We analyzed and characterized these interactions by means of density functional theory (DFT) calculations and several computational tools. Remarkably, single crystals of a solvate containing two acetonitrile molecules per calix[4]pyrrole were obtained from pure acetonitrile solution. [ABSTRACT FROM AUTHOR]

The in situ crystallization is the most suitable way to obtain a crystal of a low-melting-point compound to determine its structure via X-Ray diffraction. Herein, the intermolecular interactions and some crystal properties of low-melting-point organoelement compounds (lattice energies, melting points, etc.) are discussed. The discussed structures were divided into two groups: organoelement compounds of groups 13–16 and organofluorine compounds with other halogen atoms (Cl, Br, I). The most of intermolecular interactions in the first group are represented by weak hydrogen bonds and H···H interactions. The crystal packing of the second group of compounds is stabilized by various interactions between halogen atoms in conjunction with hydrogen bonding and stacking interactions. The data on intermolecular interactions from the analysis of crystal packing allowed us to obtain correlations between lattice energies and Hirshfeld molecular surface areas, molecular volumes, and melting points. [ABSTRACT FROM AUTHOR]

The reaction of ozone and gaseous platinum hexafluoride led to O2PtF6(s) and not the desired O3PtF6(s). Suggestions as to why the synthesis of O3PtF6(s) failed are made in terms of the known chemistry of the gaseous O cation with O proposed as an intermediate. [ABSTRACT FROM AUTHOR]

This contribution comments on the advances of the latest Crystal Structure Prediction blind test and the challenges still lying ahead. [ABSTRACT FROM AUTHOR]