scholarly journals The Ambiguous Functions of the Precursors That Enable Nonclassical Modes of Olanzapine Nucleation and Growth

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 738
Author(s):  
Monika Warzecha ◽  
Alastair J. Florence ◽  
Peter G. Vekilov

One of the most consequential assumptions of the classical theories of crystal nucleation and growth is the Szilard postulate, which states that molecules from a supersaturated phase join a nucleus or a growing crystal individually. In the last 20 years, observations in complex biological, geological, and engineered environments have brought to light violations of the Szilard rule, whereby molecules assemble into ordered or disordered precursors that then host and promote nucleation or contribute to fast crystal growth. Nonclassical crystallization has risen to a default mode presumed to operate in the majority of the inspected crystallizing systems. In some cases, the existence of precursors in the growth media is admitted as proof for their role in nucleation and growth. With the example of olanzapine, a marketed drug for schizophrenia and bipolar disorder, we demonstrate that molecular assemblies in the solution selectively participate in crystal nucleation and growth. In aqueous and organic solutions, olanzapine assembles into both mesoscopic solute-rich clusters and dimers. The clusters facilitate nucleation of crystals and crystal form transformations. During growth, however, the clusters land on the crystal surface and transform into defects, but do not support step growth. The dimers are present at low concentrations in the supersaturated solution, yet the crystals grow by the association of dimers, and not of the majority monomers. The observations with olanzapine emphasize that detailed studies of the crystal and solution structures and the dynamics of molecular association may empower classical and nonclassical models that advance the understanding of natural crystallization, and support the design and manufacture of promising functional materials.

2006 ◽  
Vol 923 ◽  
Author(s):  
Brigid R. Heywood ◽  
Adam C. D. Ovens

ABSTRACTIn this research, the ability of a series of novel oligomeric organic species to control crystal nucleation and growth of inorganic crystals was investigated. The issues under consideration were (i) the relative balance of hydrophobicity and hydrophilicity which might be programmed into a polymer; (ii) the impact metal binding, or bridging on its activity in a crystallization reaction; (iii) the mode of self organisation. An homologous series of alkyl substituted sulphonated calixarenes were used to probe these issues.The ability of a metal cation to either bridge adjacent calix[4]arenes or to adsorb into the molecular cavity had an impact upon the interaction of these molecules with the nascent crystals; selective and specific adsorption behaviours were revealed by the expression of smooth well defined new faces in the equilibrium morphology of the crystals. When the hydrophobicity index was high (increased molecular weight of alkyl substituent) these compounds segregated at the gas/liquid interface and, as a consequence of cation-induced ordering, were able to induce the oriented nucleation of crystals. When the metal ion was preferentially adsorbed into the molecular cavity the complex induced twinning in the crystal form. These studies have revealed that, in contrast to earlier studies which argued for the only for an epitaxial relationship between the polymer and crystal, a tunable range of several chemical characteristics can be programmed into a polymeric substrates if they are to be used to control nucleation and growth.


Materials ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 3640 ◽  
Author(s):  
Guijun Yang ◽  
Soo-Jin Park

We recently published an article “Conventional and Microwave Hydrothermal Synthesis and Application of Functional Materials: A Review” on Materials, and we are honored to receive a comment article from Jalouli et al. We will give a detailed explanation for the confusion of the mechanism of crystal nucleation and growth in the comment article.


2018 ◽  
Vol 11 (01) ◽  
pp. 1850002
Author(s):  
Huoshi Cen ◽  
Wenlong Liu ◽  
Zhaodong Nan

In situ microcalorimetry was first used to study the crystal formation processes of porous metal-organic frameworks (MOF), [((CH[Formula: see text]NH[Formula: see text]Cd(MIPA)][Formula: see text][Formula: see text], where H3MIPA is 5-Mercaptoisophthalic acid, G represents guest of DMA and H2O. An endothermic process occurred firstly, which is corresponding to the chemical reaction among the reactants. Exothermic processes followed the endothermal process are corresponding to crystal nucleation and growth. The experimental results demonstrate that a solid sample was first obtained at 150[Formula: see text]C for 24[Formula: see text]h. X-ray powder diffraction (XRD) peaks of the samples enhanced with the experimental time increasing from 24 to 60[Formula: see text]h (as 24, 35, 48 and 60[Formula: see text]h). The adsorption properties of the crystal obtained at 150[Formula: see text]C for 60[Formula: see text]h are more excellent than those reported and the same MOF synthesized at 150[Formula: see text]C for 72[Formula: see text]h. This study may give a method for investigation on MOFs formation mechanism and help to synthesize this kind of functional materials.


Author(s):  
G. L. Kellogg ◽  
P. R. Schwoebel

Although no longer unique in its ability to resolve individual single atoms on surfaces, the field ion microscope remains a powerful tool for the quantitative characterization of atomic processes on single-crystal surfaces. Investigations of single-atom surface diffusion, adatom-adatom interactions, surface reconstructions, cluster nucleation and growth, and a variety of surface chemical reactions have provided new insights to the atomic nature of surfaces. Moreover, the ability to determine the chemical identity of selected atoms seen in the field ion microscope image by atom-probe mass spectroscopy has increased or even changed our understanding of solid-state-reaction processes such as ordering, clustering, precipitation and segregation in alloys. This presentation focuses on the operational principles of the field-ion microscope and atom-probe mass spectrometer and some very recent applications of the field ion microscope to the nucleation and growth of metal clusters on metal surfaces.The structure assumed by clusters of atoms on a single-crystal surface yields fundamental information on the adatom-adatom interactions important in crystal growth. It was discovered in previous investigations with the field ion microscope that, contrary to intuition, the initial structure of clusters of Pt, Pd, Ir and Ni atoms on W(110) is a linear chain oriented in the <111> direction of the substrate.


Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 347
Author(s):  
Wenlin Zhang ◽  
Lingyi Zou

We apply molecular dynamics (MD) simulations to investigate crystal nucleation in incompatible polymer blends under deep supercooling conditions. Simulations of isothermal nucleation are performed for phase-separated blends with different degrees of incompatibility. In weakly segregated blends, slow and incompatible chains in crystallizable polymer domains can significantly hinder the crystal nucleation and growth. When a crystallizable polymer is blended with a more mobile species in interfacial regions, enhanced molecular mobility leads to the fast growth of crystalline order. However, the incubation time remains the same as that in pure samples. By inducing anisotropic alignment near the interfaces of strongly segregated blends, phase separation also promotes crystalline order to grow near interfaces between different polymer domains.


2013 ◽  
Vol 378 ◽  
pp. 115-120 ◽  
Author(s):  
I. Dyamant ◽  
A.S. Abyzov ◽  
V.M. Fokin ◽  
E.D. Zanotto ◽  
J. Lumeau ◽  
...  

2018 ◽  
Vol 74 (12) ◽  
pp. 1208-1218 ◽  
Author(s):  
Thomas Lykke-Møller Sørensen ◽  
Samuel John Hjorth-Jensen ◽  
Esko Oksanen ◽  
Jacob Lauwring Andersen ◽  
Claus Olesen ◽  
...  

Neutron macromolecular crystallography (NMX) has the potential to provide the experimental input to address unresolved aspects of transport mechanisms and protonation in membrane proteins. However, despite this clear scientific motivation, the practical challenges of obtaining crystals that are large enough to make NMX feasible have so far been prohibitive. Here, the potential impact on feasibility of a more powerful neutron source is reviewed and a strategy for obtaining larger crystals is formulated, exemplified by the calcium-transporting ATPase SERCA1. The challenges encountered at the various steps in the process from crystal nucleation and growth to crystal mounting are explored, and it is demonstrated that NMX-compatible membrane-protein crystals can indeed be obtained.


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