Pairwise Interaction Energies Research Articles

Structure and noncovalent interaction analysis of half-sandwich chiral-at-metal organoruthenium complexes with planar and η6-arene-metal axial chirality

The preparation of organometallic compounds has provided new molecular complexity in molecular science. The stereochemistry of organometallics has long been a great challenge due to the large atom radius and more valency. Herein, eight ruthenium piano-stool shaped Ru complexes 2a-d and 3a-d with η6-planar chirality and Ru-center chirality were successfully synthesized and resolved, and the absolute configurations were determined by X-ray diffraction analysis. Racemization experiment revealed the stability differences of the Ru complexes in various solvents. Furthermore, in asymmetric unit of complex 3b, there are two conformers bearing opposite η6-arene-Ru axial chirality. In the supramolecular organization, all of the Ru complexes are stabilized by hydrogen bonding, C-H···π and Cl/I···π interactions. π···π interaction was only observed in complex 3b. The Hirshfeld surface analysis and 2D fingerprint plot show that the eight complexes have a similar contribution composed of different noncovalent interactions to the stabilization of crystal packing. Interestingly, only complex 3b has 3.5 % C···C interaction. The pairwise interaction energies were calculated using CE-B3LYP energy model and further visualized by 3D-energy framework, which show that the dominant interaction for all complexes is dispersion. Theoretical energies of each conformer of complex 2a-d and 3a-d with η6-arene rotated at different angles were calculated by DFT method, and the energy barrier between the two conformations was around 2–3 kcal/mol. Halide ligand exchange experiments on complex (SRu)-1a were performed and the plausible mechanism was proposed. These results have provided new evidence for the design of molecules with specific fine stereochemical information for potential applications in medicinal and material chemistry.

2D hydrogen bonded organic framework (2D-HOF) in benzodioxane-coupled-pyridine as a charge carrier: Synthesis, structural, quantum computational investigation

This research presents a comprehensive investigation into the synthesis, structural features, and charge carrier properties of a novel 2D Hydrogen-Bonded Organic Framework (2D-HOF) formed by Benzodioxane-Coupled-Pyridine. The synthesis involves the reaction of 2,3-dihydrobenzo[b][1,4]dioxin-6-carbaldehyde with pyridine-2-carbohydrazide in the presence of acetic acid and ethanol solvent, leading to the formation of (E)-2-(2-((2,3-dihydrobenzo[b][1,4]dioxin-6-yl)methylene)hydrazinyl)pyridine (DDMP). Single crystal X-ray diffraction analysis reveals the monoclinic crystal system with the P21/n space group, showcasing a non-planar structure due to a distinctive twisting motion in the dioxane ring. The crystal packing is governed by a complex network of intermolecular interactions, including hydrogen bonds, short contacts, and π-stacking, ultimately forming a stable 2D-HOF. Hirshfeld Surface (HS) analysis provides insights into key interactions, emphasizing the significance of hydrogen bonding, short contacts, and stacking interactions in molecular packing. The 2D fingerprint (FP) plots quantitatively highlight crucial interatomic contacts, with hydrogen bonding, CH…H, and O…H interactions dominating. Molecular Electrostatic Potential (MEP) analysis reveals potential sites for electrophilic and nucleophilic attacks, aiding in predicting reactive sites and charge carrier behavior. Energy framework analysis sheds light on the pairwise interaction energies within the crystal structure, emphasizing the role of dispersive forces in stabilizing the crystal lattice. Density functional theory calculations indicate the molecule's charge transfer capabilities, suggesting its suitability for applications such as batteries, supercapacitors, and solar cells. Additionally, global reactivity parameters suggest that the 2D HOF material has electron and proton conduction capabilities, making it versatile for various applications. Atoms-in-molecules (AIM) topology analysis, particularly non-covalent interaction (NCI) analysis, provides a detailed understanding of intra and intermolecular interactions, highlighting hydrogen bonding and π…π interactions. H-bond binding energy analysis confirms the non-covalent nature of identified interactions, emphasizing their strength and significance.

Synthesis of organotin(IV) heterocycles containing a xanthenyl group by a Barbier approach via ultrasound activation: synthesis, crystal structure and Hirshfeld surface analysis.

A series of organotin heterocycles of general formula [{Me2C(C6H3CH2)2O}SnR2] [R= methyl (Me, 4), n-butyl (n-Bu, 5), benzyl (Bn, 6) and phenyl (Ph, 7)] was easily synthesized by a Barbier-type reaction assisted by the sonochemical activation of metallic magnesium. The 119Sn{1H} NMR data for all four compounds confirm the presence of a central Sn atom in a four-coordinated environment in solution. Single-crystal X-ray diffraction studies for 17,17-dimethyl-7,7-diphenyl-15-oxa-7-stannatetracyclo[11.3.1.05,16.09,14]heptadeca-1,3,5(16),9(14),10,12-hexaene, [Sn(C6H5)2(C17H16O)], 7, at 100 and 295 K confirmed the formation of a mononuclear eight-membered heterocycle, with a conformation depicted as boat-chair, resulting in a weak Sn...O interaction. The Sn and O atoms are surrounded by hydrophobic C-H bonds. A Hirshfeld surface analysis of 7 showed that the eight-membered heterocycles are linked by weak C-H...π, π-π and H...H noncovalent interactions. The pairwise interaction energies showed that the cohesion between the heterocycles are mainly due to dispersion forces.

Thermodynamic parameters of L-carnosine dissolution and solvation in binary aqueous-organic mixtures at T = 298.15 K.

Isothermal calorimetry was used to measure the enthalpies of L-carnosine digestion in aqueous solutions of acetonitrile (AN) 1,4-dioxane (DO), acetone (AC), dimethyl sulfoxide (DMSO), ethanol EtOH), 1-propanol (1-PrOH), and 2-propanol (2-PrOH). The values of ΔsolH° obtained were combined with the standard enthalpies of L-carnosine sublimation to obtain the corresponding enthalpies of solvation ΔsolvH°. In addition, the enthalpic coefficients of pairwise interactions (hxy) of L-carnosine with organic solvent molecules and the enthalpy of transfer (ΔtrH°) from water in their mixture with the latter were calculated. It is established that the solvation of L-carnosine is weakened in a series of (H2O + EtOH) > (H2O + 1-PrOH) > (H2O + 2-PrOH). This may be due to an increase in the hydrophobicity of alcohols of the same order as well as the presence of CH3-groups within the alcohol molecule. The weakening of the solvation energy of L-carnosine by co-solvent molecules in a series of mixed solvents: (H2O + AN) < (H2O + AC) < (H2O + DO) < (H2O + DMSO) is associated both with an increase in the hydration energy of co-solvents in the same order and with their physicochemical properties. The enthalpic coefficients of water-organic solvent pairwise interactions were discovered to be linearly related to the corresponding coefficients of L-carnosine-organic solvent interactions. An increase in the polarity and acidity of an organic solvent increases the energy of pairwise interactions between L-carnosine and the organic solvent. Increasing the cohesion energy density, molar volume, and basicity of the organic solvent reduces the energy of the pairwise interactions between L-carnosine and the organic solvent.

Explainable chemical artificial intelligence from accurate machine learning of real-space chemical descriptors

Machine-learned computational chemistry has led to a paradoxical situation in which molecular properties can be accurately predicted, but they are difficult to interpret. Explainable AI (XAI) tools can be used to analyze complex models, but they are highly dependent on the AI technique and the origin of the reference data. Alternatively, interpretable real-space tools can be employed directly, but they are often expensive to compute. To address this dilemma between explainability and accuracy, we developed SchNet4AIM, a SchNet-based architecture capable of dealing with local one-body (atomic) and two-body (interatomic) descriptors. The performance of SchNet4AIM is tested by predicting a wide collection of real-space quantities ranging from atomic charges and delocalization indices to pairwise interaction energies. The accuracy and speed of SchNet4AIM breaks the bottleneck that has prevented the use of real-space chemical descriptors in complex systems. We show that the group delocalization indices, arising from our physically rigorous atomistic predictions, provide reliable indicators of supramolecular binding events, thus contributing to the development of Explainable Chemical Artificial Intelligence (XCAI) models.

Ordered phases in ternary wurtzite group-III nitrides: A first-principles study

A first-principles-based lattice model is applied to investigate the ordered phases of mixed group-III nitride ternary alloys. The model surveys the atomistic configurations with the lowest formation enthalpy for a wide range of compositions. We found novel ordered phases in wurtzite structures having specific compositions of three- and four-sevenths molar fractions of group-III cations. The configurations of group–III atoms on cation sites in those phases consist of a characteristic fragment of the ordered phases of one-third and one-half ordered phases that were previously reported. The simulation results indicate that group-III cations in ternary nitrides follow spatial positioning “atomistic distancing rules” that can be described by the pairwise interaction energy of group-III cations to realize the stabilities of the ordered structures. To minimize the formation enthalpy of a mixed crystal, the minor B, Al, Ga, and In atoms on cation sites remain neither too close to nor too distant from each other, allowing those ordered phases to be realized.

Exploration of one-dimensional hydrogen bonding organic framework (1D-HOF) and charge transfer dynamics in N’-benzylbenzohydrazide: A comprehensive structural and quantum computational investigation

This study presents a comprehensive structural analysis of N’-benzylbenzohydrazide (NBBH) using experimental and computational techniques, shedding light on its non-covalent interactions and charge transfer dynamics. Single crystal X-ray diffraction studies confirm the three-dimensional molecular structure with high precision, revealing an orthorhombic crystal system and non-planarity of the NBBH molecule. Supramolecular interactions, including hydrogen bonds and short intermolecular interactions, are investigated, forming the basis for the assembly of molecular entities into extensive frameworks. Hirshfeld surface analysis provides insights into the intermolecular interactions in the crystal system, with the visualization of hydrogen bonds and short contacts. Energy framework analysis further explores pairwise interaction energies, emphasizing the role of dispersive forces in stabilizing the crystal lattice. Density functional theory studies, including molecular orbital analysis and global chemical reactivity descriptors, offer a deeper understanding of the electronic structure, redox potential, and charge transfer properties of NBBH. Natural bond orbital analysis reveals the charge transfer mechanism within the 1D Hydrogen-Bonded Organic chain, highlighting hyperconjugative interactions contributing to the stabilization of the molecule. Non-covalent interaction analysis using the Reduced Density Gradient method visualizes intra and intermolecular interactions, providing valuable insights into the formation and stability of the 1D network chain in the crystal structure of NBBH. Reorganization energy is discussed in the context of electron and hole transfer processes, emphasizing its importance in understanding the charge transfer dynamics within the molecular framework. The observed inverse relationship between reorganization energy and charge mobility contributes a key insight into the stability and conductivity of the material. The electron charge density distribution analysis, provides a detailed spatial distribution of electrons within the NBBH molecule. The findings have implications for understanding the molecular properties and potential applications of NBBH in various fields.

Concomitant polymorphs of 2-imino-2H-chromene-3-carboxylic acid amide: experimental and quantum chemical study.

2-Iminocoumarin-3-carboxamide (2-imino-2 H-chromene-3-carboxylic acid) is a perspective compound for use in the pharmaceutical industry. This compound crystallized from several solvents as two concomitant polymorphic forms. The monoclinic polymorph, crystallized initially, is formed due to strong N-H...O hydrogen bonds, weak C-H...O and C-H...N(π) hydrogen bonds, and stacking interactions of `head-to-head' type. The triclinic polymorphic form obtained due to slow evaporation of the same solution is formed due to only strong intermolecular interactions, N-H...O hydrogen bonds of two types, and stacking interactions of two types. Analysis of pairwise interaction energies showed that the monoclinic structure is columnar while the triclinic one is layered. Calculations in a periodic approximation of their lattice energies confirmed that the monoclinic polymorphic crystals are metastable as compared to the stable triclinic polymorph. Further quantum chemical modeling of possible structure deformations proved that both concomitant polymorphs can not be transformed into a new polymorphic form under external influence.

Directed assembly of small binary clusters of magnetizable ellipsoids.

We report the effect of shape anisotropy and material properties on the directed assembly of binary suspensions composed of magnetizable ellipsoids. In a Monte Carlo simulation, we implement the ellipsoid-dipole model to calculate the pairwise dipolar interaction energy as a function of position and orientation. The analysis explores dilute suspensions of paramagnetic and diamagnetic ellipsoids with different aspect ratios in a superparamagnetic medium. We analyze the local order of binary structures as a function of particle aspect ratio, medium permeability, and dipolar interaction strength. Our results show that local order and symmetry are tunable under the influence of a uniform magnetic field when one component of the structure is dilute with respect to the other. The simulation results match previously reported experiments on the directed assembly of binary suspension of spheres. Additionally, we report the conditions on particle aspect ratios and medium properties for various structures with rotational symmetries, as well as open and enclosed structures under the influence of a uniform magnetic field.

Isomorphic relationship between three solvates of a ferrocenyl-based chromenopyrimidine

Solvates of 4-((3-ferrocenylphenyl)amino)-5-(2-fluorophenyl)-8,8-dimethyl-5,7,8,9-tetrahydro-6H-chromeno[2,3-d]pyrimidin-6-one (I), a promising antiproliferative agent towards human breast cancer (MCF-7) cells, were formed from their respective acetone, DMSO‑d6, and DMF solutions. Isomorphic relationship exists between the solvates of I since all compounds crystallize in a P21/n space group with four molecular entities in their respective unit cells, with slight differences in their respective unit cell parameters. IR spectroscopy was used to distinguish the three solvates by monitoring the NH vibration frequency since they all have intermolecular NH…Osolvent hydrogen bonding patterns in the solid state. The solvent molecule's Hirshfeld surface helps distinguish the solvates based on the contribution of reciprocal H…O contacts. Molecular pairwise interaction energy calculations were done to determine the associated energies between solvent-I molecular pairs that are linked by the intermolecular NH…Osolvent hydrogen bond. Correlations between the geometric parameters of the NH…Osolvent hydrogen bond, NH vibration frequency, the contribution of reciprocal H…O contacts toward the solvent's Hirshfeld surface and pairwise interaction energies of the three solvates, are discussed in this work.

On the Role of Charge Transfer in Many-Body Non-Covalent Interactions.

Charge transfer is one of the mechanisms involved in non-covalent interactions. In molecular dimers, its contribution to pairwise interaction energies has been studied extensively using a variety of interaction energy decomposition schemes. In polar interactions such as hydrogen bonds, it can contribute ten or several tens of percent of the interaction energy. Less is known about its importance in higher-order interactions in many-body systems, mainly because of the lack of methods applicable to this problem. In this work, we extend our method for the quantification of the charge-transfer energy based on constrained DFT to many-body cases and apply it to model trimers extracted from molecular crystals. Our calculations show that charge transfer can account for a large fraction of the total three-body interaction energy. This also has implications for DFT calculations of many-body interactions in general as it is known that many DFT functionals struggle to describe charge-transfer effects correctly.

New Polymorphic Modifications of 6-Methyluracil: An Experimental and Quantum Chemical Study.

Polymorphism of 6-methyluracil, which affects the regulation of lipid peroxidation and wound healing, has been studied by experimental and quantum chemical methods. Two known polymorphic modifications and two new crystalline forms were crystallized and characterized by single crystal and powder X-ray diffraction (XRD) methods as well as by the differential scanning calorimetry (DSC) method and infrared (IR) spectroscopy. The calculations of pairwise interaction energies between molecules and lattice energies in periodic boundary conditions have shown that the polymorphic form 6MU_I used in the pharmaceutical industry and two new forms 6MU_III and 6MU_IV, which can be formed due to temperature violations, may be considered as metastable. The centrosymmetric dimer bound by two N-H···O hydrogen bonds was recognized as a dimeric building unit in all of the polymorphic forms of 6-methyluracil. Four polymorphic forms have a layered structure from the viewpoint of interaction energies between dimeric building units. The layers parallel to the (100) crystallographic plane were recognized as a basic structural motif in the 6MU_I, 6MU_III, and 6MU_IV crystals. In the 6MU_II structure, a basic structural motif is a layer parallel to the (001) crystallographic plane. The ratio between the interaction energies within the basic structural motif and between neighboring layers correlates with the relative stability of the studied polymorphic forms. The most stable polymorphic form 6MU_II has the most anisotropic "energetic" structure, while the interaction energies in the least stable form 6MU_IV are very close in various directions. The modeling of shear deformations of layers in the metastable polymorphic structures has not revealed any possibility of these crystals to be deformed under external mechanical stress or pressure influence. These results allow the use of metastable polymorphic forms of 6-methyluracil in the pharmaceutical industry without any limitations.

Density functional modeling of the binding energies between aluminosilicate oligomers and different metal cations

Interactions between negatively charged aluminosilicate species and positively charged metal cations are critical to many important engineering processes and applications, including sustainable cements and aluminosilicate glasses. In an effort to probe these interactions, here we have calculated the pair-wise interaction energies (i.e., binding energies) between aluminosilicate dimer/trimer and 17 different metal cations Mn+ (Mn+ = Li+, Na+, K+, Cu+, Cu2+, Co2+, Zn2+, Ni2+, Mg2+, Ca2+, Ti2+, Fe2+, Fe3+, Co3+, Cr3+, Ti4+ and Cr6+) using a density functional theory (DFT) approach. Analysis of the DFT-optimized structural representations for the clusters (dimer/trimer + Mn+) shows that their structural attributes (e.g., interatomic distances) are generally consistent with literature observations on aluminosilicate glasses. The DFT-derived binding energies are seen to vary considerably depending on the type of cations (i.e., charge and ionic radii) and aluminosilicate species (i.e., dimer or trimer). A survey of the literature reveals that the difference in the calculated binding energies between different Mn+ can be used to explain many literature observations associated with the impact of metal cations on materials properties (e.g., glass corrosion, mineral dissolution, and ionic transport). Analysis of all the DFT-derived binding energies reveals that the correlation between these energy values and the ionic potential and field strength of the metal cations are well captured by 2nd order polynomial functions (R2 values of 0.99–1.00 are achieved for regressions). Given that the ionic potential and field strength of a given metal cation can be readily estimated using well-tabulated ionic radii available in the literature, these simple polynomial functions would enable rapid estimation of the binding energies of a much wider range of cations with the aluminosilicate dimer/trimer, providing guidance on the design and optimization of sustainable cements and aluminosilicate glasses and their associated applications. Finally, the limitations associated with using these simple model systems to model complex interactions are also discussed.

Thermal transport across flat and curved gold-water interfaces: Assessing the effects of the interfacial modeling parameters.

The present investigation assesses a variety of parameters available in the literature to model gold-water interfaces using molecular dynamics simulations. The study elucidates the challenges of characterizing the solid-liquid affinity of highly hydrophilic gold-water interfaces via wettability. As an alternative, the local pairwise interaction energy was used to describe the solid-liquid affinity of flat and curved surfaces, where for the latter, the calculation of a contact angle becomes virtually impossible. Regarding the heat transfer properties of different interface models (flat and curved), partly conclusive trends were observed between the total pairwise interaction energy and the thermal boundary conductance. It was observed that the solid surface structure, interfacial force field type, and force field parameters created a characteristic bias in the interfacial water molecules (liquid structuring). Consequently, a study of the liquid depletion layer provided better insight into the interfacial heat transfer among different interfaces. By computing the density depletion length, which describes the deficit or surplus of energy carries (water molecules) near the interface, a proper characterization of the thermal boundary conductance was obtained for the different gold-water interfaces. It was observed that the interfacial heat transfer is favored when the water molecules organize in cluster-like structures near the interface, by a surplus of water molecules at the interface, i.e., lower density depletion length, and by the closeness of water to the solid atoms.

Synthesis, analysis of mol-ecular and crystal structures, estimation of inter-molecular inter-actions and biological properties of 1-benzyl-6-fluoro-3-[5-(4-methylcyclohexyl)-1,2,4-oxadiazol-3-yl]-7-(piperidin-1-yl)quinolin-4-one.

The title compound, C30H33N4O2F, can be obtained via a two-step synthetic scheme involving 1-benzyl-6-fluoro-4-oxo-7-(piperidin-1-yl)-1,4-di-hydro-quino-line-3-carbo-nitrile as a starting compound that undergoes substitution with hydroxyl-amine and subsequent cyclization with 4-methyl-cyclo-hexane-1-carb-oxy-lic acid. It crystallizes from 2-propanol in the triclinic space group P with a mol-ecule of the title compound and one of 2-propanol in the asymmetric unit. After the mol-ecular structure was clarified using NMR and LC/MS, the mol-ecular and crystalline arrangements were defined with SC-XRD. A Hirshfeld surface analysis was performed for a better understanding of the inter-molecular inter-actions. One strong (O-H⋯O) and three weak [C-H⋯F (intra-molecular) and two C-H⋯O] hydrogen bonds were found. The contributions of short contacts to the Hirshfeld surface were estimated using two-dimensional fingerprint plots showing that O⋯H/H⋯O, C⋯H/H⋯C and C⋯C contacts are the most significant for the title compound and O⋯H for the 2-propanol. The crystal structure appears to have isotropically packed tetra-mers containing two mol-ecules of the title compound and two mol-ecules of 2-propanol as the building unit according to analysis of the distribution of pairwise inter-action energies. A mol-ecular docking study was carried out to evaluate the inter-actions of the title compound with the active centers of macromolecules corresponding to viral targets, namely, anti-hepatitis B activity [HBV, capsid Y132A mutant (VCID 8772) PDB ID: 5E0I] and anti-COVID-19 main protease activity (PDB ID: 6LU7). The data obtained revealed a noticeable affinity towards them that exceeded that of the reference ligands.

Study of Thermodynamic Properties of Bi-Pb Liquid Alloy

We have used quasi-lattice theory to describe the mixing behavior of Bi-Pb liquid alloys at a temperature of 700K by computing thermodynamic functions and structural functions. The thermodynamic functions includes free energy of mixing (GM), activity (a), heat of mixing (HM), entropy of mixing (SM). The structural functions includes concentration fluctuation in the long-wavelength limit (Scc(0)) and chemical short range order parameter (α1). Most of the computed values are in good agreement with the experimental data. The pair-wise interaction energies between the species of the liquid alloys play important role and are found to temperature dependent. Theoretical analysis suggests that Pb3Bi complex exists in the liquid state at 700K. And, it has hetero-coordination (i.e. ordering) nature but is of weakly interacting in nature.

Crystallization, structural study and analysis of intermolecular interactions of a 2-aminobenzoxazole–fumaric acid molecular salt

The new organic salt, 2-aminobenzoxazol-3-ium 3-carboxyprop-2-enoate, C7H7N2O+·C4H3O4 −, of the two bioactive compounds 2-aminobenzoxazole and fumaric acid, crystallizes in the orthorhombic space group Pbca using classical evaporation of their solution in water. The usual topological analysis revealed four classical (N—H...O and O—H...O) and two non-classical (C—H...O) hydrogen bonds in the structure. Stacking was found as well for a pair of 2-aminobenzoxazolium cations. A Hirshfeld surface analysis including the two-dimensional fingerprint plots was performed to define the residual π–π interactions and to quantify the influences of different types of interactions by means of topological analysis. Analysis of the pairwise interaction energies was used to prove the formation of the corrugated paired layers of cation–anion dimers parallel to the plane (001) as a basic structural motif in the topological, as well as in the energetic structure of the crystal. It showed that the layers are connected by the hydrogen bonds inside and by stacking and π–π interactions and general dispersion between them.

Learning physics-consistent particle interactions.

Interacting particle systems play a key role in science and engineering. Access to the governing particle interaction law is fundamental for a complete understanding of such systems. However, the inherent system complexity keeps the particle interaction hidden in many cases. Machine learning methods have the potential to learn the behavior of interacting particle systems by combining experiments with data analysis methods. However, most existing algorithms focus on learning the kinetics at the particle level. Learning pairwise interaction, e.g., pairwise force or pairwise potential energy, remains an open challenge. Here, we propose an algorithm that adapts the Graph Networks framework, which contains an edge part to learn the pairwise interaction and a node part to model the dynamics at particle level. Different from existing approaches that use neural networks in both parts, we design a deterministic operator in the node part that allows to precisely infer the pairwise interactions that are consistent with underlying physical laws by only being trained to predict the particle acceleration. We test the proposed methodology on multiple datasets and demonstrate that it achieves superior performance in inferring correctly the pairwise interactions while also being consistent with the underlying physics on all the datasets. While the previously proposed approaches are able to be applied as simulators, they fail to infer physically consistent particle interactions that satisfy Newton's laws. Moreover, the proposed physics-induced graph network for particle interaction also outperforms the other baseline models in terms of generalization ability to larger systems and robustness to significant levels of noise. The developed methodology can support a better understanding and discovery of the underlying particle interaction laws, and hence, guide the design of materials with targeted properties.

Co-crystals of pyrazinamide (PZA) with terephthalic (TPH) and trimesic (TMS) acids: Structural insights and dissolution study

Two new co-crystals of pyrazinamide (PZA) with terephthalic (TPH) and trimesic (TMS) acids have been prepared and characterized by single-crystal and powder X-ray diffraction, spectroscopic and thermal analysis, and the corresponding dissolution curves are discussed. PZA-TPH co-crystal is formed by a combination of acid-py heterosynthons and amide-amide homosynthons, while in PZA-TMS co-crystal only amide-acid and acid-py heterosynthons were observed. These interactions are discussed based on hydrogen bonds and pairwise interaction energies calculated using B3LYP/6–31G(d,p) molecular wave functions. Hirshfeld surface analysis shows that the crystal structure is mainly controlled by short OH‧‧‧O, NH‧‧‧O, and OH‧‧‧N hydrogen bonds forming molecular sheets that induce preferred orientations in their powder samples. During single-crystal X-ray diffraction experiments, a sort of anisotropic X-ray induced fluorescent phenomenon was observed. PZA-TPH and PZA-TMS co-crystals present improved thermal stabilities compared to PZA. However, the solubility of co-crystals decrease compared to PZA which remarkably follows the proportionality of the conformer solubility rule. In the co-crystals, the lower solubility is due to the precipitation of the TPH and TMS acids, nevertheless, PZA molecules tend to retain a more stable concentration over time

C[sbnd]H‧‧‧X (X = F, Cl) and Cl‧‧‧Cl halogen-mediated interactions driving the crystal packing in N-substituted 4-arylimidazoles

Herein, tree imidazole derivatives named 1-(4-fluorophenyl)-2-(4-(4-fluorophenyl)-1H-imidazol-1-yl)ethan-1-one (3a), 1-(4-chlorophenyl)-2-(4-(4-chlorophenyl)-1H-imidazol-1-yl)ethan-1-one (3b), and 4-(4-chlorophenyl)-2-phenyl-1H-imidazole (4a) were analyzed in their crystal structures. Hirshfeld surface analysis, pairwise interaction energies, and electrostatic potentials (ESP) –obtained using the B3LYP method applying the 6-31G(d,p) basis set on the crystallographic information– demonstrated that CH‧‧‧O and CH‧‧‧N hydrogen interactions connect molecules in strong chains. However, CH‧‧‧X (X = F, Cl) interactions control the crystal growing by the orientation of these chains. Additionally, the presence of two chlorine atoms in the molecule of 3b allows the formation of σ-holes inducing these atoms to behave as pairs of Lewis's acid-base forming Cl‧‧‧Cl contacts, which help in the control of the crystal growth. From these results, it was confirmed that fluorine atoms do not present σ-holes in 3a and that despite the existence of σ-holes in molecules, it is necessary for the presence of halogens that also could act as Lewis's base to form X‧‧‧X interactions, which is the case of 4a.