“<i>In-Silico</i> Seeding”: Isostructurality and Pseudoisostructurality in a Family of Aspirin Derivatives

Kendrick, John; Montis, Riccardo; Hursthouse, Michael B.; Leusen, Frank J. J.

doi:10.1021/cg4003324

Cited by 8 publications

(5 citation statements)

References 37 publications

(70 reference statements)

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“…The largest deviation (−3.1%) is associated with the a parameter of the unit cell of I . The agreement between the experimental and optimised unit cells instils confidence that the DFT-D method is providing a good description of the crystals, confirming our previous experience with this method [ 22 ]–[ 27 ].…”

Section: Resultssupporting

confidence: 80%

A mechanophysical phase transition provides a dramatic example of colour polymorphism: the tribochromism of a substituted tri(methylene)tetrahydrofuran-2-one

Asiri

Heller

Hughes

et al. 2014

Chemistry Central Journal

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BackgroundDerivatives of fulgides have been shown to have interesting photochromic properties. We have synthesised a number of such derivatives and have found, in some cases, that crystals can be made to change colour on crushing, a phenomenon we have termed “tribochromism”. We have studied a number of derivatives by X-ray crystallography, to see if the colour is linked to molecular structure or crystal packing, or both, and our structural results have been supported by calculation of molecular and lattice energies.ResultsA number of 5-dicyanomethylene-4-diphenylmethylene-3-disubstitutedmethylene-tetrahydrofuran-2-one compounds have been prepared and structurally characterised. The compounds are obtained as yellow or dark red crystals, or, in one case, both. In two cases where yellow crystals were obtained, we found that crushing the crystals gave a deep red powder. Structure determinations, including those of the one compound which gave both coloured forms, depending on crystallisation conditions, showed that the yellow crystals contained molecules in which the structure comprised a folded conformation at the diphenylmethylene site, whilst the red crystals contained molecules in a twisted conformation at this site. Lattice energy and molecular conformation energies were calculated for all molecules, and showed that the conformational energy of the molecule in structure IIIa (yellow) is marginally higher, and the conformation thus less stable, than that of the molecule in structure IIIb (red). However, the van der Waals energy for crystal structure IIIa, is slightly stronger than that of structure IIIb – which may be viewed as a hint of a metastable packing preference for IIIa, overcome by the contribution of a more stabilising Coulomb energy to the overall more favourable lattice energy of structure IIIb.ConclusionsOur studies have shown that the crystal colour is correlated with one of two molecular conformations which are different in energy, but that the less stable conformation can be stabilised by its host crystal lattice.Graphical abstractGraphical representation of the structural and colour change in the tribochromic compound (III).Electronic supplementary materialThe online version of this article (doi:10.1186/s13065-014-0070-3) contains supplementary material, which is available to authorized users.

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Section: Resultssupporting

confidence: 80%

A mechanophysical phase transition provides a dramatic example of colour polymorphism: the tribochromism of a substituted tri(methylene)tetrahydrofuran-2-one

Asiri

Heller

Hughes

et al. 2014

Chemistry Central Journal

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“…The chlorine-containing species were clearly detected in the commercial products by EI-MS analysis as the mono-, di-, tri-, and tetrachloro derivatives (see Supporting Information). Solid solutions involving the replacement of drug molecules with their halogen-substituted analogue have been reported in the literature and are ascribed to the similar molecular shape of the molecules involved. − …”

Section: Resultsmentioning

confidence: 98%

Diversity through Similarity: A World of Polymorphs, Solid Solutions, and Cocrystals in a Vial of 4,4′-Diazopyridine

Mazzeo

Carraro

Arns

et al. 2019

Crystal Growth & Design

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4,4′-Diazopyridine (AP) is largely known for its photophysical properties, and it is extensively studied in solution as molecular switch. By contrast, AP is not similarly explored in the solid state. We here discuss the fine crystallographic interpretation of the electron density maps combined with occupancy refinement of solid solutions, cocrystals and solid solution of cocrystals of AP and some halogenated derivatives, obtained as a result of recrystallization experiments. AP halogenated derivatives are contained as impurities in the purchased starting material and present a remarkable propensity to give cocrystals or solid solutions along with AP. A new AP polymorph (AP2) has also been identified, and phase evolution as a function of temperature has been investigated by differential scanning calorimetry and variable temperature X-ray powder diffraction.

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“…Although impurities are well-known to impact crystal habit, slow nucleation and crystallization kinetics and impact polymorphism, 7-10 their role in forming solid solutions and the resulting impact on polymorphism has been explored only rarely. [30][31][32][33][34][35][36] To the best of our knowledge, this study shows for the first time experimentally and computationally that impurities can invert the thermodynamic stability of polymorphs through the formation of solid solutions. This mechanism may be able to explain the appearance and disappearance of some polymophs.…”

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confidence: 72%

Switching Polymorph Stabilities with Impurities: A Thermodynamic Route to Benzamide Form III

Kras¹,

Carletta²,

Montis³

et al. 2020

Preprint

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We investigate the polymorphic behavior of benzamide, the first compound known to exhibit polymorphism, in the presence of small amounts of nicotinamide in the crystallization environment. A previous study by Emmerling et al.<sup>1</sup> showed that the presence of nicotinamide promotes the transformation of the thermodynamic polymorph I of benzamide into its metastable polymorph III via mechanochemistry. We show that this transformation is the result of a thermodynamic switch between these two polymorphic forms driven by the formation of solid solutions with a small amount of nicotinamide. The presence of nicotinamide in the crystallization environment promotes the robust and exclusive crystallization of the elusive form III. These results represent a promising route to the synthesis and utilization of elusive polymorphs of pharmaceutical interest.

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“In-Silico Seeding”: Isostructurality and Pseudoisostructurality in a Family of Aspirin Derivatives

Cited by 8 publications

References 37 publications

A mechanophysical phase transition provides a dramatic example of colour polymorphism: the tribochromism of a substituted tri(methylene)tetrahydrofuran-2-one

A mechanophysical phase transition provides a dramatic example of colour polymorphism: the tribochromism of a substituted tri(methylene)tetrahydrofuran-2-one

Diversity through Similarity: A World of Polymorphs, Solid Solutions, and Cocrystals in a Vial of 4,4′-Diazopyridine

Switching Polymorph Stabilities with Impurities: A Thermodynamic Route to Benzamide Form III

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