Search Results (5)

Polymorphism is a prevalent occurrence in pharmaceutical solids and demands thorough investigation during product development. This paper delves into the crystal growth and structure of a newly synthesized polymorph (TPT)₂[Co^II(NCS)₄], (1), where TPT is triphenyl tetrazolium. The study combines experimental and theoretical approaches to elucidate the 3D framework of the crystal structure, characterized by hydrogen-bonded interactions between (TPT)⁺ cations and [Co(NCS)₄]²⁻ anions. Hirshfeld surface analysis, along with associated two-dimensional fingerprints, is employed to comprehensively investigate and quantify intermolecular interactions within the structure. The enrichment ratio is calculated for non-covalent contacts, providing insight into their propensity to influence crystal packing interactions. Void analysis is conducted to predict the mechanical behavior of the compound. Utilizing Bravais-Friedel, Donnay-Harker (BFDH), and growth morphology (GM) techniques, the external morphology of (TPT)₂[Co^II(NCS)₄] is predicted. Experimental observations align well with BFDH predictions, with slight deviations from the GM model. Quantum computational calculations of the synthesized compounds is performed in the ground state using the DFT/UB3LYP level of theory. These calculations assess the molecule’s stability and chemical reactivity, including the computation of the HOMO-LUMO energy difference and other chemical descriptors. The study provides a comprehensive exploration of the newly synthesized polymorph, shedding light on its crystal structure, intermolecular interactions, mechanical behavior, and external morphology, supported by both experimental and computational analyses. Full article

A novel method to generate an aluminum-based MOF material named as MIL-121 was investigated. MIL-121, [Al(OH)(H₂BTEC)·(H₂O)]n is a prototypal aluminum MOF with 1,2,4,5-benzenetetracarboxylic acid (BTEC) linkers, which was normally produced by the hydrothermal method. Different from the hydrothermal method, the developed novel method does not involve high temperature and high pressure, instead the MOF material was produced by the traditional cooling crystallization method at ambient pressure and low temperature below 100 °C. The MIL-121 obtained by the novel method possesses the same lithium adsorption performance as that obtained by hydrothermal method, but with lower energy consumption and more environmentally friendly. Compared with hydrothermal method, this method has more advantage to be scaled up to industrialized production. The formation mechanism of MIL-121 in the novel method including nucleation and growth process of MOF crystal was studied. The results indicated that the size and morphology of MIL-121 crystals were influenced by the temperature and additives, respectively. As the reaction temperature increased to 100 °C, the operation time can be shortened to 2–5 h. The crystal habit that was predicted by Material studio software using BFDH, which is a model for crystal habit prediction proposed by Bravais, Friedel, Donnay, and Harker based on the crystal lattice parameters and crystal symmetry in the Morphology module, the simulated morphology of MIL-121 was in accord with that of the products obtained by cooling crystallization. The thermal stability of MIL-121 obtained by cooling crystallization is better than that obtained by the hydrothermal method. Full article

The Bi₄I₁₆·4(C₆H₉N₂) 2(H₂O) compound was synthesized by slow evaporation at room temperature. It exhibits a zero-dimensional (0D) tetrameric structure, comprising [Bi₄I₁₆]⁴⁻ distorted octahedra, with strong I⋯I interactions among adjacent anionic clusters. We used Hirshfeld surface analysis to discuss the strength of hydrogen bonds and to quantify the inter-contacts (two-dimensional (2D) fingerprint plots). It revealed that the hydrogen bonding interactions H⋯I (56.3%), π–π stacking (11.7%), and I⋯I interactions (5.9%) play the major role in the stability of the crystal structure. The crystal morphology was simulated using Bravais–Friedel, Donnay–Harker (BFDH) and growth morphology (GM) methods. The experimental habit of the title compound was adequately reproduced by the two models. The calculated results show that the crystal morphology of the title compound in a vacuum is dominated by five facets: (020), (011), (110), (10−1), and (11−1). The (020) facet is the largest among all the facets calculated. Projection of the facet showed that there are a few polar groups on the (020) facet. In the 50–400 and 400–4000 cm⁻¹ frequency regions, we measured the Raman and infrared spectra, respectively, of the title compound, and we assigned the observed vibration modes. Full article

A new polymorph of 1H-nicotineamidium chloride salt, (C₆H₇N₂O)⁺·Cl⁻, was grown by slow evaporation at room temperature. It crystallizes in the monoclinic space group P2₁/m. The crystal structure study shows that the organic cations (C₆H₇N₂O)⁺ and chloride anions are organized into 2D-layers packed along the b-axis. The structural components interact by N–H···O, N–H···Cl and C–H···Cl hydrogen bonds building up a two-dimensional network. The protonated organic cations and the chloride anions show a π–Cl⁻ interaction enhancing stability to the crystal structure. A description of the hydrogen-bonding network and comparison with similar related compounds of nicotinamide and isonicotineamide are presented. The bulk morphology was also predicted and it was found that the simulated morphology predicted by Bravais–Friedel–Donnay–Harker (BFDH) model matches with the morphology of as grown single crystal. Moreover, to illustrate the intermolecular interactions in the new studied polymorph, we report also the analysis of the Hirshfeld surface and its fingerprint polts. Full article

Three new enantiopure aryl-thioureas have been synthesized, N-(4-X-phenyl)-N-[1(S)-1-phenylethyl]thiourea, X= Cl, Br, and NO₂ (compounds 1-3, respectively). Large single crystals of up to 0.5 cm³ were grown from methanol/ethanol solutions. Molecular structures were derived from X-ray diffraction studies and the crystal morphology was compared to calculations employing the Bravais-Friedel, Donnay-Harker model. Molecular packing was further studied with Hirshfeld surface calculations. Semi-empirical classical model calculations of refractive indices, optical rotation and the electro-optic effect were performed with OPTACT on the basis of experimentally determined refractive indices. Compound 3 (space group P 1 (No. 1)) was estimated to possess a large electro-optic coefficient r₃₃₃ of approximately 30 pm/V, whereas 1 and 2 (space Group P 2₁ (No. 4) exhibit much smaller effects. Full article