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Crystal Growth & Design

Senja Barthel, Eugeny V Alexandrov, Davide M Proserpio, Berend Smit
We consider two metal-organic frameworks as identical if they share the same bond network respecting the atom types. An algorithm is presented that decides whether two metal-organic frameworks are the same. It is based on distinguishing structures by comparing a set of descriptors that is obtained from the bond network. We demonstrate our algorithm by analyzing the CoRe MOF database of DFT optimized structures with DDEC partial atomic charges using the program package ToposPro.
March 7, 2018: Crystal Growth & Design
M M H Smets, G Baaklini, A Tijink, L Sweers, C H F Vossen, C Brandel, H Meekes, H M Cuppen, G Coquerel
Tailor-made additives can prove an effective method to prolong the lifetime of metastable forms of pharmaceutical compounds by surface stabilization. Pyrazinamide (PZA) is a pharmaceutical compound with four polymorphic forms. The high temperature γ form, which can be produced by spray drying or sublimation growth, is metastable at room temperature and transforms within days when produced by spray drying, and within several months up to years for single crystals produced by sublimation. However, when PZA is cospray dried with 1,3-dimethylurea (DMU), it has been reported to remain in its γ form for several years...
February 7, 2018: Crystal Growth & Design
Bin Chen, Dennis de Wal, Gert H Ten Brink, George Palasantzas, Bart J Kooi
Chalcogenide-based phase change materials (PCMs) are promising candidates for the active element in novel electrical nonvolatile memories and have been applied successfully in rewritable optical disks. Nanostructured PCMs are considered as the next generation building blocks for their low power consumption, high storage density, and fast switching speed. Yet their crystallization kinetics at high temperature, the rate-limiting property upon switching, faces great challenges due to the short time and length scales involved...
February 7, 2018: Crystal Growth & Design
Christopher R Taylor, Graeme M Day
We present a periodic density functional theory study of the stability of 350 organic cocrystals relative to their pure single-component structures, the largest study of cocrystals yet performed with high-level computational methods. Our calculations demonstrate that cocrystals are on average 8 kJ mol -1 more stable than their constituent single-component structures and are very rarely (<5% of cases) less stable; cocrystallization is almost always a thermodynamically favorable process. We consider the variation in stability between different categories of systems-hydrogen-bonded, halogen-bonded, and weakly bound cocrystals-finding that, contrary to chemical intuition, the presence of hydrogen or halogen bond interactions is not necessarily a good predictor of stability...
February 7, 2018: Crystal Growth & Design
Wester de Poel, Joris A W Münninghoff, Johannes A A W Elemans, Willem J P van Enckevort, Alan E Rowan, Elias Vlieg
Surfaces with controllable topography and chemistry were prepared to act as substrates for protein crystallization, in order to investigate the influence of these surface properties on the protein crystallization outcome. Three different methods were investigated to deposit 1,3,5-tris(10-carboxydecyloxy)benzene (TCDB) on a muscovite mica substrate to find the best route for controlled topography. Of these three, sublimation worked best. Contact angle measurements revealed that the surfaces with short exposure to the TCDB vapor (20 min or less) are hydrophilic, while surfaces exposed for 30 min or longer are hydrophobic...
February 7, 2018: Crystal Growth & Design
Wester de Poel, Paul T Tinnemans, Alexander L L Duchateau, Maarten Honing, Floris P J T Rutjes, Elias Vlieg, René de Gelder
The use of an achiral metal-organic framework for structure determination of chiral compounds is demonstrated for camphene and pinene. The structure of enantiopure β-pinene can be resolved using the crystalline sponge method. However, α-pinene cannot be resolved using enantiopure material alone because no ordering of guest molecules takes place in that case. Interestingly, enantiomeric pairs order inside the channels of the host framework when impure (+)-camphene is offered to the host, which is also the case when a racemic mixture of α-pinene is used...
January 3, 2018: Crystal Growth & Design
Rahimah Othman, Goran T Vladisavljević, Elena Simone, Zoltan K Nagy, Richard G Holdich
Microcrystals of piroxicam (PRX) monohydrate with a narrow size distribution were prepared from acetone/PRX solutions by antisolvent crystallization via metallic membranes with ordered pore arrays. Crystallization was achieved by controlled addition of the feed solution through the membrane pores into a well-stirred antisolvent. A complete transformation of an anhydrous form I into a monohydrate form of PRX was confirmed by Raman spectroscopy and differential scanning calorimetry. The size of the crystals was 7-34 μm and was controlled by the PRX concentration in the feed solution (15-25 g L-1), antisolvent/solvent volume ratio (5-30), and type of antisolvent (Milli-Q water or 0...
December 6, 2017: Crystal Growth & Design
Maximilian O Besenhard, Peter Neugebauer, Otto Scheibelhofer, Johannes G Khinast
Size, shape, and polymorphic form are the critical attributes of crystalline particles and represent the major focus of today's crystallization process design. This work demonstrates how crystal properties can be tuned efficiently in solution via a tubular crystallizer that facilitates rapid temperature cycling. Controlled crystal growth, dissolution, and secondary nucleation allow a precise control of the crystal size and shape distribution, as well as polymorphic composition. Tubular crystallizers utilizing segmented flow such as the one presented in our work can provide plug flow characteristics, fast heating and cooling, allowing for rapid changes of the supersaturation...
December 6, 2017: Crystal Growth & Design
Leyla-Cann Sögütoglu, Martin Lutz, Hugo Meekes, René de Gelder, Elias Vlieg
The crystal structure of para-methyl-l-phenylalanine at 230 K resembles that of the para-fluorinated analogue from the literature but is commensurately modulated with seven molecules in the asymmetric unit (Z' = 7). At 100 K, the superstructure loses its modulation, leading to a unit cell with Z' = 1, with clear disorder in the phenyl ring orientations. The methyl-substituent in para-methyl-l-phenylalanine has, in contrast to fluorine, no polar interactions with protons of neighboring molecules, which might allow for the well-defined modulation of the crystal structure at 230 K...
December 6, 2017: Crystal Growth & Design
Anthonius H J Engwerda, Pim van Schayik, Henjo Jagtenberg, Hugo Meekes, Floris P J T Rutjes, Elias Vlieg
The scope of Viedma ripening and temperature cycling with respect to chiral molecules has remained mostly limited to molecules with a single stereogenic center, while racemization proceeds through inversion at that particular stereocenter. In this article we demonstrate for the first time that atropisomers, chiral rotamers that possess an axis of chirality, can be successfully deracemized in the solid phase by either applying temperature cycling or Viedma ripening.
October 4, 2017: Crystal Growth & Design
Doris E Braun, Sreenivas R Lingireddy, Mark D Beidelschies, Rui Guo, Peter Müller, Sarah L Price, Susan M Reutzel-Edens
The solid form landscape of 5-HT2a antagonist 3-(4-(benzo[d]isoxazole-3-yl)piperazin-1-yl)-2,2-dimethylpropanoic acid hydrochloride (B5HCl) proved difficult to establish. Many crystalline materials were produced by solid form screening, but few forms readily grew high quality crystals to afford a clear picture or understanding of the solid form landscape. Careful control of crystallization conditions, a range of experimental methods, computational modeling of solvate structures, and crystal structure prediction were required to see potential arrangements of the salt in its crystal forms...
October 4, 2017: Crystal Growth & Design
Kyle A Nordquist, Kevin M Schaab, Jierui Sha, Andrew H Bond
Systematic surface energy modifications to glass substrates can induce nucleation and improve crystallization outcomes for small molecule active pharmaceutical ingredients (APIs) and proteins. A comparatively broad probe for function is presented in which various APIs, proteins, organic solvents, aqueous media, surface energy motifs, crystallization methods, form factors, and flat and convex surface energy modifications were examined. Replicate studies (n ≥ 6) have demonstrated an average reduction in crystallization onset times of 52(4)% (alternatively 52 ± 4%) for acetylsalicylic acid from 91% isopropyl alcohol using two very different techniques: bulk cooling to 0 °C using flat surface energy modifications or microdomain cooling to 4 °C from the interior of a glass capillary having convex surface energy modifications that were immersed in the solution...
August 2, 2017: Crystal Growth & Design
Anthonius H J Engwerda, Niels Koning, Paul Tinnemans, Hugo Meekes, F Matthias Bickelhaupt, Floris P J T Rutjes, Elias Vlieg
Despite the importance of enantiopure chiral sulfoxides, few methods exist that allow for their deracemization. Here, we show that an enantiopure sulfoxide can be produced from the corresponding racemate using Viedma ripening involving rearrangement-induced racemization. The suitable candidate for Viedma ripening was identified from a library of 24 chiral sulfoxides through X-ray structure determination. Starting from the racemic sulfoxide, an unprecedented application of a 2,3-sigmatropic rearrangement type racemization in a Viedma ripening process allowed for complete deracemization...
August 2, 2017: Crystal Growth & Design
Rohit Kacker, Marilena Radoiu, Herman J M Kramer
The control of nucleation in crystallization processes is a challenging task due to the often lacking knowledge on the process kinetics. Inflexible (predetermined) control strategies fail to grow the nucleated crystals to the desired quality because of the variability in the process conditions, disturbances, and the stochastic nature of crystal nucleation. Previously, the concept of microwave assisted direct nucleation control (DNC) was demonstrated in a laboratory setup to control the crystal size distribution in a batch crystallization process by manipulating the number of particles in the system...
July 5, 2017: Crystal Growth & Design
Andrii Ishchenko, Lingling Peng, Egor Zinovev, Alexey Vlasov, Sung Chang Lee, Alexander Kuklin, Alexey Mishin, Valentin Borshchevskiy, Qinghai Zhang, Vadim Cherezov
Lipidic cubic phase (LCP) has been widely recognized as a promising membrane-mimicking matrix for biophysical studies of membrane proteins and their crystallization in a lipidic environment. Application of this material to a wide variety of membrane proteins, however, is hindered due to a limited number of available host lipids, mostly monoacylglycerols (MAGs). Here, we designed, synthesized and characterized a series of chemically stable lipids resistant to hydrolysis, with properties complementary to the widely used MAGs...
June 7, 2017: Crystal Growth & Design
Eleanor R Townsend, Willem J P van Enckevort, Jan A M Meijer, Elias Vlieg
This article investigates the mechanism behind the creeping of sodium chloride induced by additives. Here, an experimental approach is complemented with theoretical considerations to describe how creeping patterns of brine evolve and how the introduction of additives into the solution affects the morphology of the resultant crystals. We have found that these additives cause kinetic roughening and morphological instability mainly due to the reduction of surface free energy. There was also a marked increase in three-dimensional nucleation of the NaCl crystals and thus branching...
June 7, 2017: Crystal Growth & Design
Laura N Poloni, Zina Zhu, Nelson Garcia-Vázquez, Anthony C Yu, David M Connors, Longqin Hu, Amrik Sahota, Michael D Ward, Alexander G Shtukenberg
l-Cystine kidney stones-aggregates of single crystals of the hexagonal form of l-cystine-afflict more than 20 000 individuals in the United States alone. Current therapies are often ineffective and produce adverse side effects. Recognizing that the growth of l-cystine crystals is a critical step in stone pathogenesis, real-time in situ atomic force microscopy of growth on the (0001) face of l-cystine crystals and measurements of crystal growth anisotropy were performed in the presence of prospective inhibitors drawn from a 31-member library...
May 3, 2017: Crystal Growth & Design
Elena Simone, Anneke R Klapwijk, Chick C Wilson, Zoltan K Nagy
Crystal size and shape can be manipulated to enhance the qualities of the final product. In this work the steady-state shape and size of succinic acid crystals, with and without a polymeric additive (Pluronic P123) at 350 mL, scale is reported. The effect of the amplitude of cycles as well as the heating/cooling rates is described, and convergent cycling (direct nucleation control) is compared to static cycling. The results show that the shape of succinic acid crystals changes from plate- to diamond-like after multiple cycling steps, and that the time required for this morphology change to occur is strongly related to the type of cycling...
April 5, 2017: Crystal Growth & Design
Doris E Braun, Ulrich J Griesser
Computational methods were used to generate and explore the crystal structure landscapes of the two alkaloids strychnine and brucine. The computed structures were analyzed and rationalized by correlating the modelling results to a rich pool of available experimental data. Despite their structural similarity, the two compounds show marked differences in the formation of solid forms. For strychnine only one anhydrous form is reported in the literature and two new solvates from 1,4-dioxane were detected in the course of this work...
November 2, 2016: Crystal Growth & Design
Jana Broecker, Viviane Klingel, Wei-Lin Ou, Aidin R Balo, David J Kissick, Craig M Ogata, Anling Kuo, Oliver P Ernst
In recent years, in situ data collection has been a major focus of progress in protein crystallography. Here, we introduce the Mylar in situ method using Mylar-based sandwich plates that are inexpensive, easy to make and handle, and show significantly less background scattering than other setups. A variety of cognate holders for patches of Mylar in situ sandwich films corresponding to one or more wells makes the method robust and versatile, allows for storage and shipping of entire wells, and enables automated crystal imaging, screening, and goniometer-based X-ray diffraction data-collection at room temperature and under cryogenic conditions for soluble and membrane-protein crystals grown in or transferred to these plates...
November 2, 2016: Crystal Growth & Design
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