Influence of magnetic field on the nucleation rate control of mono paracetamol

Sudha, Chellamma; Sivanarendiran, R.; Srinivasan, K.

doi:10.1002/crat.201400432

Cited by 13 publications

(20 citation statements)

References 29 publications

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“…At such a stage the magnetic field may play a more significant role in altering the thermodynamic landscape. Applied magnetic fields have previously been found to affect the nucleation and growth rate of inorganic systems, proteins and paracetamol [38][39][40] . Enhanced growth rates induced by the magnetic field are especially notable; since there is strong evidence that the growth rate and not the nucleation rate can be the key kinetic factor in determining which polymorph dominates during crystallization 41,42 .…”

Section: Ring Currents Enable Polymorphismmentioning

confidence: 99%

An unforeseen polymorph of coronene by the application of magnetic fields during crystal growth

et al. 2016

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The continued development of novel drugs, proteins, and advanced materials strongly rely on our ability to self-assemble molecules in solids with the most suitable structure (polymorph) in order to exhibit desired functionalities. The search for new polymorphs remains a scientific challenge, that is at the core of crystal engineering and there has been a lack of effective solutions to this problem. Here we show that by crystallizing the polyaromatic hydrocarbon coronene in the presence of a magnetic field, a polymorph is formed in a β-herringbone structure instead of the ubiquitous γ-herringbone structure, with a decrease of 35° in the herringbone nearest neighbour angle. The β-herringbone polymorph is stable, preserves its structure under ambient conditions and as a result of the altered molecular packing of the crystals, exhibits significant changes to the optical and mechanical properties of the crystal.

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Section: Ring Currents Enable Polymorphismmentioning

confidence: 99%

An unforeseen polymorph of coronene by the application of magnetic fields during crystal growth

et al. 2016

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“…We could explain crystallization of thin films in magnetic fields by the effect of ground vs excited states of metals, or by valence electron ordering. However, these two approaches were chosen based on the formation of metal ions in liquids and alloys [37] and the size of atom/ion/molecule effect [38]. Aluminium belongs to the boron group and, therefore, has three electrons in the last orbital with valence configuration ns 2 np 1 .…”

Section: Discussionmentioning

confidence: 99%

Inducing Crystallinity of Metal Thin Films with Weak Magnetic Fields without Thermal Annealing

et al. 2018

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Since the discovery of thin films, it has been known that higher crystallinity demands higher temperatures, making the process inadequate for energy-efficient and environmentally friendly methods of thin film fabrication. We resolved this problem by sparking metal wires in a 0.4 Tesla magnetic field at ambient conditions under ultra-pure nitrogen flow to replace the annealing of thin films, and thus designed an environmentally friendly and energy-efficient thin film fabrication method. We employed grazing incidence X-Ray Diffraction spectroscopy to characterize crystallinity of Iron, Nickel, Copper and Tungsten thin films prepared by a sparking discharge process in the presence of 0.4 T magnetic field at an ambient temperature of 25 °C. Control experiment was conducted by sparking without a magnetic field present and using ultra-pure nitrogen flow and ambient air containing oxygen. The Iron thin film prepared in ultra-pure nitrogen flow preserved crystallinity even after one year of ageing. Nickel exhibited higher crystallinity when sparked in nitrogen gas flow than when sparked in atmospheric air and was the only element to crystalize under atmospheric air. Tungsten successfully crystalized after just 40 min of sparking and aluminium failed to crystalize at all, even after 12 h of sparking under nitrogen flow.

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“…11 Crystals grown in magnetic fields have also been observed to have a different morphology and nucleation rate. 12 The much stronger magnetic fields around white dwarf stars, up to 10 5 T, have been shown to promote a new bonding mechanism, perpendicular paramagnetic bonding, in hydrogen. 13 When a diamagnetic molecule is put in a laboratory external magnetic field B, the motion of its electrons and nuclei is perturbed.…”

Section: Introductionmentioning

confidence: 99%

Calculation of Diamagnetic Susceptibility Tensors of Organic Crystals: From Coronene to Pharmaceutical Polymorphs

et al. 2020

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Understanding why crystallization in strong magnetic fields can lead to new polymorphs requires methods to calculate the diamagnetic response of organic molecular crystals. We develop the calculation of the macroscopic diamagnetic susceptibility tensor, χ cryst , for organic molecular crystals using periodic density functional methods. The crystal magnetic susceptibility tensor, χ cryst , for all experimentally known polymorphs, and its molecular counterpart, χ mol , are calculated for flexible pharmaceuticals such as carbamazepine, flufenamic acid, and chalcones, and rigid molecules, such as benzene, pyridine, acridine, anthracene, and coronene, whose molecular magnetic properties have been traditionally studied. A tensor addition method is developed to approximate the crystal diamagnetic susceptibility tensor, χ cryst , from the molecular one, χ mol , giving good agreement with those calculated directly using the more costly periodic density functional method for χ cryst . The response of pharmaceutical molecules and crystals to magnetic fields, as embodied by χ cryst , is largely determined by the packing in the crystal, as well as the molecular conformation. The anisotropy of χ cryst can vary considerably between polymorphs though the isotropic terms are fairly constant. The implications for developing a computational method for predicting whether crystallization in a magnetic field could produce a novel or different polymorph are discussed.

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Influence of magnetic field on the nucleation rate control of mono paracetamol

Cited by 13 publications

References 29 publications

An unforeseen polymorph of coronene by the application of magnetic fields during crystal growth

An unforeseen polymorph of coronene by the application of magnetic fields during crystal growth

Inducing Crystallinity of Metal Thin Films with Weak Magnetic Fields without Thermal Annealing

Calculation of Diamagnetic Susceptibility Tensors of Organic Crystals: From Coronene to Pharmaceutical Polymorphs

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