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  • 1.
    Abebe, Mihret
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Hedin, Niklas
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Bacsik, Zoltan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Spherical and Porous Particles of Calcium Carbonate Synthesized with Food Friendly Polymer Additives2015Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 15, nr 8, s. 3609-3616Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Porous calcium carbonate particles were synthesized by adding solutions of Ca2+ to solutions of CO32- containing polymeric additives. Under optimized conditions well-defined aggregates of the anhydrous polymorph vaterite formed. A typical sample of these micrometer-sized aggregates had: a pore volume of 0.1 cm(3)/g, a pore width of similar to 10 nm, and a specific surface area of similar to 25-30 m(2)/ g. Only one mixing Order (calcium to carbonate) allowed the formation of vaterite, which was ascribed to the buffering capacity and relatively high pH of the CO32- solution. Rapid addition of the calcium chloride solution and rapid stirring promoted the formation of vaterite, due to the high supersaturation levels achieved. With xanthan gum, porous and micrometer-sized vaterite aggregates could be synthesized over a wide range of synthetic conditions. For the Other food grade polymers, hydroxypropyl methylcellulose (HPMC), methylcellulose (MC), and sodium carboxyl methylcellulose, several intensive and extensive synthetic parameters had to be optimized to obtain pure vaterite and porous aggregates. HPMC and MC allowed well-defined spherical micrometer-sited particles to form. We expect that these spherical and porous particles of vaterite could be relevant to model studies as well as a controlled delivery of particularly large molecules.

  • 2.
    Agarwal, Parminder
    et al.
    Michigan State University.
    Berglund, Kris
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Effect of polymeric additives on calcium carbonate crystallization as monitored by nephelometry2004Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 4, nr 3, s. 479-483Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The effect of polymaleimide polymers on calcium carbonate crystallization was studied using nephelometry. Induction time and percent growth inhibition were determined for polymeric additives from the nephelometric data. The polymaleimide synthesized by KOH-initiated polymerization exhibited the greatest growth inhibition and longest nucleation time among the polymers investigated. Raman spectroscopy was used to determine the calcium carbonate polymorph formed in the presence of these polymeric additives.

  • 3.
    Agarwal, Parminder
    et al.
    Michigan State University.
    Berglund, Kris
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    In situ monitoring of calcium carbonate polymorphs during batch crystallization in the presence of polymeric additives using Raman spectroscopy2003Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 3, nr 6, s. 941-946Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Polycarboxylic acids are well-known to affect calcium carbonate crystallization. Agarwal et al. (Ind. Eng. Chem. Res. 2003, in press) reported previously the synthesis of polymaleimide by a variety of techniques and initiators. In the present work, the effect of these polymers on calcium carbonate crystallization was studied by a variety of techniques. Crystallization experiments were carried out in a 1-L LABMAX automated batch reactor, and the concentration of calcium in solution was determined in real time. Raman spectroscopy was used to determine the relative amount of various calcium carbonate polymorphs as the crystallization occurred. However, Raman spectroscopy is a scattering technique, which may make it surface selective, and therefore results from solids may not be representative of bulk of sample. X-ray diffraction (XRD) was used to compare the results obtained by Raman spectroscopy. Peak intensity ratios were used for both Raman spectroscopy and XRD for calibration and measurement purposes. The results obtained by these two techniques for final percent vaterite for calcium carbonate crystallization in the presence of polymeric additives were in agreement within 2%. Therefore, use of Raman spectroscopy for in situ measurement of polymorph composition during calcium carbonate crystallization appears accurate. Scanning electron microscopy (SEM) data were useful in understanding the crystal morphology and to determine crystal size.

  • 4. Alhalaweh, Amjad
    et al.
    Ali, Hassan
    Velaga, Sitaram
    Luleå tekniska universitet, Institutionen för hälsovetenskap, Medicinsk vetenskap.
    Effects of polymer and surfactant on the dissolution and transformation profiles of cocrystals in aqueous media2014Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 14, nr 2, s. 643-648Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Capturing solubility advantages of cocrystals is of great interest, and thus to understand the mechanism by which different excipients could maintain the supersaturation generated by cocrystals at the course of absorption in aqueous media is essential. To achieve this aim, the impact of different excipients on dissolution behavior of indomethacin-saccharin (IND-SAC) were monitored by measuring the concentrations of cocrystal components in the absence and presence of various concentration of excipients by HPLC, and solid phases were analyzed by differential scanning calorimetry after each experiment and the potential of Raman spectroscopy for monitoring phase transformations in situ was tested. No dissolution advantage was offered by cocrystals in the absence of any solution additive. The polymer and surfactant used in the study increased the solubility of IND but not SAC. This differential solubilization effect is believed to have stabilized the cocrystals for a relevant period for the absorption to take place. This could be attributed to either decreased gap between supersaturation and saturation of the drug or drug interaction with the additives. Understanding the effects of excipients type and concentration on the transformation profile is vital for designing enabling formulations for cocrystals. The eutectic constant may be useful in selecting excipients for stabilizing cocrystals.

  • 5.
    Alhalaweh, Amjad
    et al.
    Luleå tekniska universitet, Institutionen för hälsovetenskap, Medicinsk vetenskap.
    George, Sumod
    Boström, Dan
    Department of Energy Technology and Thermal Process Chemistry, Umea University.
    Velaga, Sitaram
    Luleå tekniska universitet, Institutionen för hälsovetenskap, Medicinsk vetenskap.
    1:1 and 2:1 urea-succinic acid cocrystals: structural diversity, solution chemistry, and thermodynamic stability2010Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 10, nr 11, s. 4847-4855Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The aim of this work was to study the crystal structures of 1:1 and 2:1 urea-succinic acid (U-SA) cocrystals and to investigate the role of solution chemistry in the formation and stability of different stoichiometric cocrystals. The structural diversity of other urea-dicarboxylic acid cocrystals is also discussed. The 1:1 U-SA cocrystal was stabilized by an acid-amide heterosynthon while acid-amide heterosynthons and amide-amide homosynthons stabilized the 2:1 cocrystals. The hydrogen bonding motifs in 1:1 and 2:1 U-SA cocrystals were consistent with other urea-dicarboxylic acid systems with similar stoichiometries. The 1:1 cocrystals were transformed to 2:1 cocrystals upon slurrying in various solvents at 25 °C. The phase solubility diagram was used to define the stability regions of different solid phases in 2-propanol at 25 °C. While no phase stability region for 1:1 cocrystal could be found, the stable regions for the 2:1 cocrystals and their pure components were defined by eutectic points. The solubility of the 2:1 cocrystals was dependent on the concentration of the ligand in the solution and explained by the solubility product and 1:1 solution complexation. The mathematical models predicting the solubility of the 2:1 cocrystals were evaluated and found to fit the experimental data

  • 6. Alhalaweh, Amjad
    et al.
    George, Sumod
    Boström, Dan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik, Energiteknik och termisk processkemi.
    Velaga, Sitaram P.
    1:1 and 2:1 urea-Succinic acid cocrystals: structural diversity, solution chemistry, and thermodynamic stability2010Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 10, nr 11, s. 4847-4855Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The aim of this work was to study the crystal structures of 1:1 and 2:1 urea-succinic acid (U-SA) cocrystals and to investigate the role of solution chemistry in the formation and stability of different stoichiometric cocrystals. The structural diversity of other urea-dicarboxylic acid cocrystals is also discussed. The 1:1 U-SA cocrystal was stabilized by an acid-amide heterosynthon while acid-amide heterosynthons and amide amide homosynthons stabilized the 2:1 cocrystals. The hydrogen bonding motifs 1:1 and 2:1 U-SA cocrystals were consistent with other urea-dicarboxylic acid systems with similar stoichiometrics. The 1:1 cocrystals were transformed to 2:1 cocrystals upon slurrying in various solvents at 25 degrees C. The phase solubility diagram was used to define the stability regions of different solid phases in 2-propanol at 25 degrees C. While no phase stability region for 1:1 cocrystal could be found, the stable regions for the 2:1 cocrystals and their pure components were defined he eutectic points. The solubility of the 2:1 cocrystals was dependent on the concentration of the ligand in the solution and explained by the solubility product and 1:1 solution complexation. The mathematical models predicting the solubility of the 2:1 cocrystals were evaluated and found to fit the experimental data.

  • 7.
    Alhalaweh, Amjad
    et al.
    Luleå tekniska universitet, Institutionen för hälsovetenskap, Medicinsk vetenskap.
    Sokolowski, Anders
    Department of Pharmaceutical Chemistry, Uppsala University.
    Rodriguez-Hornedo, Nair
    Department of Pharmaceutical Sciences, University of Michigan.
    Velaga, Sitaram
    Luleå tekniska universitet, Institutionen för hälsovetenskap, Medicinsk vetenskap.
    Solubility behavior and solution chemistry of indomethacin cocrystals in organic solvents2011Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 11, nr 9, s. 3923-3929Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The main objective of this study was to investigate the solubility behavior and solution chemistry of indomethacin-saccharin (IND-SAC) cocrystals in organic media. We also evaluated previously proposed models of cocrystal solubility in organic solvents. In addition, the solubility behavior of IND-SAC cocrystals was compared with that of indomethacin-nicotinamide (IND-NIC) cocrystals using the eutectic constant approach. Phase solubility diagrams of IND-SAC cocrystals in various solvents were generated and the transition concentrations, at which drug and cocrystals are in equilibrium with the solvents, were determined. The solubility of IND-SAC cocrystals was explained by the solubility product and solution complexation. The tested models were found to fit the experimental data and to adequately explain the solubility behavior of the cocrystals. The solution complexation of IND and SAC is negligible in ethyl acetate and low in methanol and ethanol. The IND-NIC cocrystals were more soluble than the IND-SAC cocrystals in all the solvents studied. The eutectic constants predicted both the solubility and the stability of the cocrystals. Understanding the solubility behavior and solution chemistry of cocrystals has important implications for the screening, scale-up, and formulation development of this solid form. Further, the determination of eutectic constants is a simple and resource sparing means of obtaining key information on cocrystal stability and solution behavior

  • 8. Alhalaweh, Amjad
    et al.
    Sokolowski, Anders
    Uppsala universitet, Medicinska och farmaceutiska vetenskapsområdet, Farmaceutiska fakulteten, Institutionen för läkemedelskemi.
    Rodriguez-Hornedo, Nair
    Velaga, Sitaram P.
    Solubility Behavior and Solution Chemistry of Indomethacin Cocrystals in Organic Solvents2011Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 11, nr 9, s. 3923-3929Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The main objective of this study was to investigate the solubility behavior and solution chemistry of indomethacin-saccharin (IND-SAC) cocrystals in organic media. We also evaluated previously proposed models of cocrystal solubility in organic solvents. In addition, the solubility behavior of IND-SAC cocrystals was compared with that of indomethacin-nicotinamide (IND-NIC) cocrystals using the eutectic constant approach. Phase solubility diagrams of IND-SAC cocrystals in various solvents were generated and the transition concentrations, at which drug and cocrystals are in equilibrium with the solvents, were determined. The solubility of IND-SAC cocrystals was explained by the solubility product and solution complexation. The tested models were found to fit the experimental data and to adequately explain the solubility behavior of the cocrystals. The solution complexation of IND and SAC is negligible in ethyl acetate and low in methanol and ethanol. The IND-NIC cocrystals were more soluble than the IND-SAC cocrystals in all the solvents studied. The eutectic constants predicted both the solubility and the stability of the cocrystals. Understanding the solubility behavior and solution chemistry of cocrystals has important implications for the screening, scale-up, and formulation development of this solid form. Further, the determination of eutectic constants is a simple and resource sparing means of obtaining key information on cocrystal stability and solution behavior.

  • 9.
    Alhalaweh, Amjad
    et al.
    Luleå tekniska universitet, Institutionen för hälsovetenskap, Medicinsk vetenskap.
    Velaga, Sitaram
    Luleå tekniska universitet, Institutionen för hälsovetenskap, Medicinsk vetenskap.
    Formation of cocrystals from stoichiometric solutions of incongruently saturating systems by spray drying2010Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 10, nr 8, s. 3302-3305Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Spray drying is a well established technique for material processing and scale-up. This study investigated the formation of pharmaceutical cocrystals by spray drying. The cocrystal formation mechanisms in spray-drying and solution methods, based on triangular phase diagrams, are discussed. The solvent evaporation of stoichiometric solutions of incongruently saturating cocrystals resulted in a mixture of phases, as dictated by the thermodynamic phase diagram. In contrast, spray drying of similar solutions of incongruently saturating systems generated pure cocrystals. It is thus suggested that the formation of cocrystals by spray drying could be kinetically controlled and/or mediated by the glassy state of the material.

  • 10.
    Basavoju, Srinivas
    et al.
    Luleå tekniska universitet, Institutionen för hälsovetenskap, Medicinsk vetenskap.
    Boström, Dan
    Energy Technology and Thermal Process Chemistry, Umeå University.
    Velaga, Sitaram
    Luleå tekniska universitet, Institutionen för hälsovetenskap, Medicinsk vetenskap.
    Pharmaceutical cocrystal and salts of norfloxacin2006Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 6, nr 12, s. 2699-2708Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The aim of this study was to investigate the structural and pharmaceutical properties of norfloxacin (a poorly soluble antibacterial drug), its cocrystal, and salts. Norfloxacin in the anhydrous form (form A, 1) was crystallized. It was cocrystallized with isonicotinamide (2), and organic salts were prepared with succinic acid, malonic acid, and maleic acid (3-5, respectively). These phases were characterized by differential scanning calorimetry (DSC), infrared (IR) and Raman spectroscopy, and powder X-ray diffraction (PXRD). Single-crystal X-ray diffraction data were obtained, and crystal structures were solved. The apparent solubility of these phases was determined. Robust O-H⋯O, O-H⋯O-, O-H⋯N, N-H⋯O, N+-H-O -, and N-H⋯N interactions were present in all these structures. Quinolone moieties in these structures stack with π⋯π interactions and form channels to include CHCl3 or H2O. Herein we report a new cocrystal and salts of norfloxacin with improved aqueous solubility

  • 11. Basavoju, Srinivas
    et al.
    Boström, Dan
    Umeå universitet, Teknisk-naturvetenskapliga fakulteten, Institutionen för tillämpad fysik och elektronik, Energiteknik och termisk processkemi.
    Velaga, Sitaram P.
    Pharmaceutical cocrystal and salts of norfloxacin2006Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 6, nr 12, s. 2699-2708Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The aim of this study was to investigate the structural and pharmaceutical properties of norfloxacin ( a poorly soluble antibacterial drug), its cocrystal, and salts. Norfloxacin in the anhydrous form ( form A, 1) was crystallized. It was cocrystallized with isonicotinamide ( 2), and organic salts were prepared with succinic acid, malonic acid, and maleic acid (3-5, respectively). These phases were characterized by differential scanning calorimetry (DSC), infrared (IR) and Raman spectroscopy, and powder X-ray diffraction (PXRD). Single-crystal X-ray diffraction data were obtained, and crystal structures were solved. The apparent solubility of these phases was determined. Robust O-H center dot center dot center dot O, O-H center dot center dot center dot O-, O-H center dot center dot center dot N, N-H center dot center dot center dot O, N+- H center dot center dot center dot O-, and N-H center dot center dot center dot N interactions were present in all these structures. Quinolone moieties in these structures stack with pi...pi interactions and form channels to include CHCl3 or H2O. Herein we report a new cocrystal and salts of norfloxacin with improved aqueous solubility.

  • 12.
    Berglund, Kris
    et al.
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Falcon, Javier A
    Departments of Chemistry, Chemical Engineering & Materials Science and Agricultural Engineering, Michigan State University, East Lansing, Michigan.
    In situ monitoring of antisolvent addition crystallization with principal components analysis of Raman spectra2004Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 4, nr 3, s. 457-463Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Fiber optic Raman spectroscopy was used for in situ monitoring of antisolvent addition crystallization of progesterone. Raman spectral features of the solute and the antisolvent were subjected to principal components analysis (PCA) to attempt to obtain information that is not readily apparent from the raw spectral data. For the system utilized, PCA was able to distinguish spectral features from the solute in solution, the solute crystals, and the antisolvent. Furthermore, PCA was capable of detecting subtle changes in the spectral data (as the addition of antisolvent progressed) that could be used as a warning for the onset of crystallization. The current study demonstrates the advantages that can be gained by combining PCA with Raman spectroscopy for monitoring crystallizations in situ.

  • 13.
    Booker, Ian Don
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Ul Hassan, Jawad
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Lilja, Louise
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Beyer, Franziska
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Karhu, Robin
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Bergman, J. Peder
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Danielsson, Örjan
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Kordina, Olof
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Sveinbjörnsson, Einar
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Janzén, Erik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Carrier Lifetime Controlling Defects Z(1/2) and RB1 in Standard and Chlorinated Chemistry Grown 4H-SiC2014Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 14, nr 8, s. 4104-4110Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    4H-SiC epilayers grown by standard and chlorinated chemistry were analyzed for their minority carrier lifetime and deep level recombination centers using time-resolved photoluminescence (TRPL) and standard deep level transient spectroscopy (DLTS). Next to the well-known Z(1/2) deep level a second effective lifetime killer, RB1 (activation energy 1.05 eV, electron capture cross section 2 x 10(-16) cm(2), suggested hole capture cross section (5 +/- 2) x 10(-15) cm(2)), is detected in chloride chemistry grown epilayers. Junction-DLTS and bulk recombination simulations are used to confirm the lifetime killing properties of this level. The measured RB1 concentration appears to be a function of the iron-related Fe1 level concentration, which is unintentionally introduced via the corrosion of reactor steel parts by the chlorinated chemistry. Reactor design and the growth zone temperature profile are thought to enable the formation of RB1 in the presence of iron contamination under conditions otherwise optimal for growth of material with very low Z(1/2) concentrations. The RB1 defect is either an intrinsic defect similar to RD1/2 or EH5 or a complex involving iron. Control of these corrosion issues allows the growth of material at a high growth rate and with high minority carrier lifetime based on Z(1/2) as the only bulk recombination center.

  • 14.
    Bradley, Jonathan P.
    et al.
    Department of Physics, Warwick University, Coventry.
    Velaga, Sitaram
    Luleå tekniska universitet, Institutionen för hälsovetenskap, Medicinsk vetenskap.
    Antzutkin, Oleg
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Brown, Steven P.
    Department of Physics, Warwick University, Coventry.
    Probing intermolecular crystal packing in gamma-indomethacin by high-resolution 1H solid-state NMR spectroscopy2011Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 11, nr 8, s. 3463-3471Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    An NMR crystallography approach that combines experimental solid-state magic-angle-spinning (MAS) NMR with calculation is applied to the gamma polymorph of the pharmaceutical molecule, indomethacin. First-principles calculations (GIPAW) for the full crystal structure and an isolated molecule show changes in the (1)H chemical shift for specific aliphatic and aromatic protons of over -1 ppm that are due to intermolecular CH-pi interactions. For the OH proton, (1)H double-quantum (DQ) CRAMPS (combined rotation and multiple-pulse spectroscopy) spectra reveal intermolecular H-H proximities to the OH proton of the carboxylic acid dimer as well as to specific aromatic CH protons. The enhanced resolution in (1)H DQ-(13)C spectra, recorded at 850 MHz, enables separate (1)H DQ build-up curves (as a function of the DQ recoupling time) to be extracted for the aromatic CH protons. Supported by eight-spin density-matrix simulations, it is shown how the relative maximum intensities and rates of build-up provide quantitative insight into intramolecular and intermolecular H-H proximities that characterize the crystal packing

  • 15. Brent, Rhea
    et al.
    Stevens, Sam M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK), Avdelningen för oorganisk kemi och strukturkemi.
    Terasaki, Osamu
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK), Avdelningen för oorganisk kemi och strukturkemi.
    Anderson, Michael W.
    Coaxial Core Shell Overgrowth of Zeolite L - Dependence on Original Crystal Growth Mechanism2010Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 10, nr 12, s. 5182-5186Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this study, the first reported core-shell material combining zeolite L (LTL) and barium-exchanged zeolite L (Ba-LTL) is described The use of atomic force microscopy to probe the LTL surface growth mechanism was employed to understand the growth pattern of the resultant Ba-LTL coaxial overgrowth layer Additionally the dependence of the original crystal surface on the resulting habit of the Ba-LTL core-shell layer is explained High-resolution scanning electron microscopy (HRSEM) was employed to observe the fine detail of the Ba-LTL layer, and cross-sectional polishing was used to view the boundary between the two crystalline materials

  • 16.
    Carson, Fabian
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Su, Jie
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Platero-Prats, Ana E.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Wan, Wei
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Yun, Yifeng
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Samain, Louise
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Zou, Xiaodong
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Framework Isomerism in Vanadium Metal-Organic Frameworks: MIL-88B(V) and MIL-101(V)2013Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 13, nr 11, s. 5036-5044Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Two families of metal organic frameworks (MOFs), MIL-88 and MIL-101 built by trinuclear transition metal (TM) clusters (TM = Cr, Fe, or Sc), have been known for several years, but their syntheses are often reported separately. In fact, these MOFs are polymorphs, or framework isomers: they are assembled from the same metal secondary building units and organic linkers, but the connectivity of these components differs. Here we report for the first time the synthesis of the vanadium MOF MIL-88B(V) and compare its synthesis parameters to those of MIL-47(V) and the recently reported MIL-101(V). The properties of MIL-88B(V) and MIL-101(V) are remarkably different. MIL-88B(V) can breathe and is responsive to different solvents, while MIL-101(V) is rigid and contains mesoporous cages. MIL-101(V) exhibits the highest specific surface area among vanadium MOFs discovered so far. In addition, both MIL-88B(V) and MIL-101(V) transform to MIL-47 at higher temperatures. We have also identified the key synthesis parameters that control the formation of MIL-88B(V), MIL-101(V), and MIL-47: temperature, time, and pH. This relates to the rate of reaction between the metal and linkers, which has been monitored by ex situ X-ray powder diffraction and V K-edge X-ray absorption spectroscopy during MOF synthesis. It is therefore important to fully study the synthesis conditions to improve our understanding of framework isomerism in MOFs.

  • 17. Celania, Chris
    et al.
    Smetana, Volodymyr
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK). U.S. Department of Energy, United States.
    Provino, Alessia
    Manfrinetti, Pietro
    Mudring, Anja-Verena
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK). U.S. Department of Energy, United States; Iowa State University, United States.
    R-14(Au, M)(51) (R = Y, La-Nd, Sm-Tb, Ho, Er, Yb, Lu; M = Al, Ga, Ge, In, Sn, Sb, Bi): Stability Ranges and Site Preference in the Gd14Ag51 Structure Type2018Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 18, nr 2, s. 993-1001Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Twenty new ternary representatives of the Gd14Ag51 structure type have been synthesized within the R-Au-M family (R = Y, La-Nd, Sm-Tb, Ho, Er, Yb, Lu; M = Al, Ga, Ge, Sn, Sb, Bi) using solid state synthesis techniques. The list of post transition metals (M) involved in the formation of this type of structure could be augmented by five new representatives. All compounds crystallize in the hexagonal space group P6/m (#175) with the unit cell ranges of a = 12.3136(2)-12.918(1) angstrom and c = 8.9967(3)-9.385(1) angstrom, and incorporate different degrees of Au/M mixing. The involvement of the post transition element in the structure varies from one to another compound both qualitatively and quantitatively. A rather significant phase width can be expected for the majority of compounds, however, not without exclusions. The distribution of the post transition metals within the structure has been analyzed via single crystal X-ray diffraction. While the positional disorder of one near-origin Au position is expectable for all compounds due to steric reasons, two specimens show an obvious deviation from the others including another Au position split along the c axis. Possible factors affecting this behavior are discussed.

  • 18.
    Chattoraj, Sayantan
    et al.
    Pharmaceutical Materials Science & Engineering Laboratory, Department of Pharmaceutics, University of Minnesota.
    Shi, Limin
    Pharmaceutical Materials Science & Engineering Laboratory, Department of Pharmaceutics, University of Minnesota.
    Chen, Miles
    Pharmaceutical Materials Science & Engineering Laboratory, Department of Pharmaceutics, University of Minnesota.
    Alhalaweh, Amjad
    Velaga, Sitaram
    Luleå tekniska universitet, Institutionen för hälsovetenskap, Medicinsk vetenskap.
    Sun, Changquan Calvin
    Pharmaceutical Materials Science & Engineering Laboratory, Department of Pharmaceutics, University of Minnesota.
    Origin of Deteriorated Crystal Plasticity and Compaction Properties of a 1:1 Cocrystal between Piroxicam and Saccharin2014Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 14, nr 8, s. 3864-3874Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The 1:1 cocrystal between piroxicam and saccharin exhibits significantly deteriorated powder compaction properties compared to both coformers. The molecular origin of this effect is revealed by a systematic investigation of crystal mechanical properties, probed with nanoindentation, and crystal structure analysis. The order of bulk powder tabletability of the three materials is identical to that of single crystal plasticity (saccharin > piroxicam > cocrystal). The lowest plasticity of the cocrystal is confirmed by its highest crystal hardness and the highest yield strength. The low plasticity of the cocrystal is attributed to structural packing features that discourage plastic deformation. This work demonstrates that cocrystallization, even though it may be useful to improve pharmaceutically relevant properties, must be carefully evaluated to avoid unexpected problems in formulation and drug product manufacturing due to compromised mechanical properties.

  • 19. Cho, Hae Sung
    et al.
    Hill, Adam R.
    Cho, Minhyung
    Miyasaka, Keiichi
    Jeong, Kyungmin
    Anderson, Michael W.
    Kang, Jeung Ku
    Terasaki, Osamu
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK). Korea Advanced Institute of Science and Technology (KAIST), Republic of Korea; School of Physical Science and Technology, China.
    Directing the Distribution of Potassium Cations in Zeolite-LTL through Crown Ether Addition2017Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 17, nr 9, s. 4516-4521Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We discover that the crystal morphology of zeolite-LTL could be modified by crown ether (21-crown-7, CE), where CE decreases the aspect ratio of zeolite-LTL while increasing the nucleation of domains on the (0001) face and hindering their growth along the c-axes. Moreover, the study using scanning electron microscopy supports that the ratio between the rates for generation of cancrinite columns and bridging cancrinite columns on the {10 (1) over bar0} face remains constant among the LTL frameworks with different amounts of CE molecules. In addition, X-ray diffraction analysis shows that potassium cations redistribute into pore cavities (t-lil) from cancrinite cages (t-can) and t-ste cages by the strong interactions between potassium and CE as the amount of CE molecules is increased. Additionally, Monte Carlo simulations clarify that stabilization of the t-lil cage via the redistribution of potassium cations at high CE concentration is attributed to the dominant effect in the crystal morphology changes observed. To understand the catalytic and adsorption properties of zeolites, it is important to investigate their structure/property relationships. Especially, studying the morphology of an anisotropic zeolite crystals has been of great interest because of the strong influence on controlling its properties. Thus, morphological control of the material with a particular crystallographic direction is highly desirable to obtain maximum properties for applications.

  • 20.
    Chubarov, Mikhail
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Pedersen, Henrik
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Högberg, Hans
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Jensen, Jens
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Tunnfilmsfysik. Linköpings universitet, Tekniska högskolan.
    Henry, Anne
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Growth of High Quality Epitaxial Rhombohedral Boron Nitride2012Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 12, nr 6, s. 3215-3220Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Epitaxial growth of sp(2)-hybridized boron nitride (sp(2) BN) films on sapphire substrates is demonstrated in a hot wall chemical vapor deposition reactor at the temperature of 1500 degrees C, using triethyl boron and ammonia as precursors. The influence of the main important process parameters, temperature, N/B ratio, B/H-2 ratio, and carrier gas composition on the quality of the grown layers is investigated in detail. X-ray diffraction shows that epitaxial rhombohedral BN (r-BN) film can be deposited only in a narrow process parameter window; outside this window either turbostratic-BN or amorphous BN is favored if BN is formed. In addition, a thin strained AlN buffer layer is needed to support epitaxial growth of r-BN film on sapphire since only turbostratic BN is formed on sapphire substrate. The quality of the grown film is also affected by the B/H-2 ratio as seen from a change of the spacing between the basal planes as revealed by X-ray diffraction. Time-of-flight elastic recoil detection analysis shows an enhancement of the C and O impurities incorporation at lower growth temperatures. The gas phase chemistry for the deposition is discussed as well as the impact of the growth rate on the quality of the BN film.

  • 21.
    Cichocka, Magdalena O.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Lorgouilloux, Yannick
    Smeets, Stef
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Su, Jie
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Wan, Wei
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Caullet, Philippe
    Bats, Nicolas
    McCusker, Lynne B.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK). ETH Zurich, Switzerland.
    Paillaud, Jean-Louis
    Zou, Xiaodong
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Multidimensional Disorder in Zeolite IM-18 Revealed by Combining Transmission Electron Microscopy and X-ray Powder Diffraction Analyses2018Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 18, nr 4, s. 2441-2451Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A new medium-pore germanosilicate, denoted IM-18, with a three-dimensional 8 x 8 x 10-ring channel system, has been prepared hydrothermally using 4-dimethylaminopyridine as an organic structure-directing agent (OSDA). Due to the presence of stacking disorder, the structure elucidation of IM-18 was challenging, and a combination of different techniques, including electron diffraction, high-resolution transmission electron microscopy (HRTEM), and Rietveld refinement using synchrotron powder diffraction data, was necessary to elucidate the details of the structure and to understand the nature of the disorder. Rotation electron diffraction data were used to determine the average structure of IM-18, HRTEM images to characterize the stacking disorder, and Rietveld refinement to locate the Ge in the framework and the OSDA occluded in the channels.

  • 22. Codan, L.
    et al.
    Casillo, S.
    Bäbler, Matthäus U.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Teknisk strömningslära.
    Mazzotti, M.
    Phase diagram of a chiral substance exhibiting oiling out. 2. Racemic compound forming ibuprofen in water2012Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 12, nr 11, s. 5298-5310Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This work investigates the ternary phase behavior of the two enantiomers of ibuprofen and water. The two enantiomers crystallize as a racemic compound and exhibit a thermodynamically stable liquid-liquid phase separation (LLPS), which extends over the entire enantiomeric composition range. First, the generic phase behavior of racemic compound forming systems exhibiting a stable LLPS is derived by exploiting the consolidated knowledge of conglomerate forming systems obtained in the first part of this series. Below the onset temperature of the LLPS, the system behaves like a typical racemic compound forming system. As for conglomerate forming systems, the onset of the LLPS is found to occur through a ternary monotectic equilibrium, where a new, solute-rich liquid phase emerges inside each solid-solid-liquid phase region. Then, the ternary phase diagram of the ibuprofen/water system in the temperature range from 40 to 82 °C is presented together with the outcome of a thorough experimental investigation. Our theoretical considerations are in excellent agreement with experimental results.

  • 23. Codan, Lorenzo
    et al.
    Bäbler, Matthäus
    Institute of Process Engineering, ETH Zurich.
    Mazzotti, Marco
    Phase Diagram of a Chiral Substance Exhibiting Oiling Out in Cyclohexane2010Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 10, nr 9, s. 4005-4013Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This work investigates the ternary phase diagram of the enantiomers of ethyl-2-ethoxy-3-(4-hydroxyphenyl)propanoate (EEHP) in cyclohexane. The enantiomers of EEHP form aconglomerate, and both the pure enantiomer and the racemic mixture exhibit stable oilingout in cyclohexane. Our analysis shows that the ternary phase diagram of such a system assumes a unique structural evolution around the onset temperature of oiling out; that is, we found that the onset of oiling out strictly occurs through the emergence of a second liquid phase of racemic composition. Furthermore, we found that the further evolution of the ternary phase diagram, i.e., above the onset temperature of oiling out, is dictated by the properties of the phase diagrams pure enantiomer/solvent and racemic mixture/solvent. Our theoretical considerations are in excellent agreement with experimental measurements of EEHP in cyclohexane. 

  • 24. Croker, D. M.
    et al.
    Davey, R. J.
    Rasmuson, Åke Christoffer
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik. Univ Limerick, Mat & Surface Sci Inst, Dept Chem & Environm Sci.
    Seaton, C. C.
    Nucleation in the p-toluenesulfonamide/triphenylphosphine oxide co-crystal system2013Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 13, nr 8, s. 3754-3762Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Nucleation has been studied in pure co-crystal and mixed co-crystal phase regions of the ternary phase diagram (TPD) in acetonitrile at 20 C using cooling crystallization experiments. Direct nucleation of each of the co-crystal phases in this system was independently observed in regions of the TPD where each is stable. In mixed regions, regions where either a co-crystal and a coformer, or both co-crystals, are stable, the phase that initially nucleated was a function of the mass composition in that region. The relative amount of each phase nucleating could be controlled by adjusting the relative mass fraction of each component. The kinetic return to equilibrium was also observed as the systems were held over time, with the selected mass fractions always returning to the equilibrium dictated by the TPD after 24 h

  • 25.
    Croker, Denise
    et al.
    Chemical and Environmental Science, University of Limerick, Ireland.
    Foreman, Michael
    University of Cork, Ireland.
    Hogan, Bridget
    University of Cork, Ireland.
    Maguire, Nuala
    University of Cork, Ireland.
    Curtis, Elcoate
    University of Cork, Ireland.
    Hodnett, Kieran
    Chemical and Environmental Science, University of Limerick, Ireland.
    Maguire, Anita
    University of Cork, Ireland.
    Rasmuson, Åke C.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Teknisk strömningslära. Univ Limerick, Ireland.
    Lawrence, Simon
    University of Cork, Ireland.
    Understanding the p-toluenesulfonamide / triphenylphosphine oxide crystal chemistry: a new 1:1 cocrystal and ternary phase diagram2012Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 12, nr 2, s. 869-875Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A novel 1:1 cocrystal between p-toluenesulfonamide and triphenylphosphine oxide has been prepared and structurally characterized. This 1:1 cocrystal was observed to form during solid state grinding experiments, with subsequent formation of a known 3:2 cocrystal in the presence of excess sulfonamide. Both cocrystals are stable in the solid state. The ternary phase diagram for the two coformers was constructed in two different solvents: acetonitrile and dichloromethane. Examination of these diagrams clarified solution crystallization of both the newly discovered 1:1 cocrystal and the previously reported 3:2 cocrystal, and identified regions of stability for each cocrystal in each solvent. The choice of solvent was found to have a significant effect on the position of the solid state regions within a cocrystal system.

  • 26. Cubillas, Pablo
    et al.
    Castro, Maria
    Jelfs, Kim E.
    Lobo, Alan J. W.
    Slater, Ben
    Lewis, Dewi W.
    Wright, Paul A.
    Stevens, Sam M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK), Avdelningen för oorganisk kemi och strukturkemi.
    Anderson, Michael W.
    Spiral Growth on Nanoporous Silicoaluminophosphate STA-7 as Observed by Atomic Force Microscopy2009Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 9, nr 9, s. 4041-4050Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Atomic force microscopy was used to study the surface of STA-7 crystals. STA-7 is a silicoaluminophosphate, nanoporous solid formed by interlinked double six ring units (D6R). Observations showed the formation of three distinct types of spirals at tow supersaturation conditions. The {001} face shows spirals with isotropic shapes and a Burgers vector of 0.9 nm, which corresponds to one D6R or one unit cell along the < 001 > direction. The {100} face contains two distinct types of spirals. The first has a Burgers vector of 0.9 rim, or half a unit cell along < 100 >. This dislocation produces a change in the ""stacking"" sequence of the D6Rs generating all overgrowth with the AEI structure. The second type is an interlaced spiral and is generated by a dislocation with a Burgers vector of 1.8 nm or one unit cell, leading to the formation of two substeps each with a different growth anisotropy. This anisotropy is directed by the shape of the substep and the energetics of template attachment. The preponderance of a surface coating of a secondary phase will have significant consequences on applications reliant on intracrystalline diffusion, such as catalysis, where, owing to diffusion limitations, the outermost structure dominates the functional properties.

  • 27.
    Doe, Maofeng
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Flerskalig materialmodellering.
    Persson, Clas
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Flerskalig materialmodellering. Department of Physics, University of Oslo, Norway .
    Analysis of the Semi local States in ZnO-InN Compounds2014Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 14, nr 10, s. 4937-4943Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    ZnO alloys are extensively explored for the developments of optoelectronics. In this work we analyze the rather unconventional type of ZnO-based compound ZnOX (ZnO)(1y)Xy with X = InN. The compound forms alloy with ZnO and/or assembles cluster structures in the ZnO host. Importantly, this type of alloy benefits from being isovalent which implies a more stable crystalline structure, and at the same time it benefits from the oxynitride anion-alloying that alters the optoelectronic properties. Theoretical studies reveal that incorporating InN in ZnO strongly narrows the fundamental band gap energy Eg. For example, the (ZnO)(0.875)(InN)(0.125) alloy has the gap energy E-g = 2.20 eV = E-g(ZnO) 1.14 eV. The origin of this effect is a hybridization of the anion N 2p-like and O 2p-like orbitals. Intriguingly, the presence of InN nanoclusters enhances this effect and narrows the gap further, and moreover, the nanostructured configurations show more disperse energy distribution of the hybridized anion states compared with the random alloy. Nanoclustering affects the ZnO host more compared to structures with more random distribution of the InN dimers. On the basis of the different characters of the alloys and the nanostructures, we conclude that fine-tuned synthesizing of the (ZnO)(1-y)(InN)(y) alloys can be beneficial for a variety of novel nanosystems for optoelectronic and photoelectrochemical applications.

  • 28.
    Falcon, Javier A.
    et al.
    Michigan State University.
    Berglund, Kris
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    Monitoring of antisolvent addition crystallization with Raman spectroscopy2003Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 3, nr 6, s. 947-952Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Fiber optic Raman spectroscopy was used for in situ monitoring of antisolvent addition crystallization of cortisone acetate. Raman spectral features of the solvent, the antisolvent, and the solute were monitored to measure the relative concentration of the components. Different rates of antisolvent addition were monitored and the resulting solid-state form was characterized using Raman spectroscopy and DSC. Raman spectroscopy was used to monitor dehydration during storage of the product crystals. The current study demonstrates the advantages of using Raman spectroscopy to monitor the solution phase during crystallization and simultaneously monitoring the solid-state form.

  • 29.
    Fang, Liang
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Liu, Leifeng
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Yun, Yifeng
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Inge, A. Ken
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Wan, Wei
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Zou, Xiaodong
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Geo, Feifei
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    SU-77: An Open-Framework Germanate Containing 12 × 10 × 10-Ring Channels Solved by Combining Rotation Electron Diffraction and Powder X-ray Diffraction2014Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 14, nr 10, s. 5072-5078Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A novel open-framework germanate, denoted as SU-77, was prepared by hydrothermal synthesis using ethylenediamine as the structure directing agent. The as-synthesized SU-77 is monoclinic with space group P21/a and a = 13.52427(5) Å, b = 12.64862(5) Å, c = 9.60578(3) Å, β = 92.8599(4)°. The structure of SU-77 is built from a novel Ge6O17(C2H8N2)F (Ge6) cluster building unit. The Ge6 clusters are connected to form chains along the c-axis. These chains are further connected in the [110] and [1–10] directions to form a three-dimensional framework with 12 × 10 × 10-ring channels. The as-synthesized monoclinic SU-77 became orthorhombic while being observed in a transmission electron microscope (TEM) or when heated to 200 °C in air. The orthorhombic structure of SU-77 was solved from micrometer-sized crystals by rotation electron diffraction (RED). The monoclinic structure was built from the orthorhombic structure and subsequently refined against synchrotron powder X-ray diffraction data. SU-77 is the first example of an open-framework germanate with mixed coordination polyhedra solved by electron diffraction.

  • 30.
    Feng, Lili
    et al.
    Michigan State University.
    Berglund, Kris
    Luleå tekniska universitet, Institutionen för samhällsbyggnad och naturresurser, Industriell miljö- och processteknik.
    ATR-FTIR for determining optimal cooling curves for batch crystallization of succinic acid2002Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 2, nr 5, s. 449-452Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The temperature profile applied during batch cooling crystallization affects the supersaturation level, which in turn affects the crystal size distribution. It is possible, in principle, to calculate the optimal cooling profile; however, the nucleation and growth kinetics are rarely known to the degree of accuracy necessary for this calculation. The current study demonstrates an alternative approach to determination of the optimal cooling profile without any prior knowledge of kinetic data or subsequent modeling. An attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectrometer was used to monitor the supersaturation level during batch cooling crystallization. The ATR-FTIR was interfaced to a LABMAX automatic reactor system that was used in a feedback mode to control the cooling rate so that the supersaturation level remained close to the solubility throughout the cooling process. The resulting temperature profile corresponds to the optimal operating conditions for the maximum in the mean crystal size.

  • 31.
    Fornasari, Luca
    et al.
    Dipartimento di Chimica “Giacomo Ciamician”, Università; di Bologna, Bologna, Italy.
    Mazzaro, Raffaello
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap. CNR-IMM, Area della Ricerca di Bologna, Bologna, Italy.
    Boanini, Elisa
    Dipartimento di Chimica “Giacomo Ciamician”, Università; di Bologna, Bologna, Italy.
    d’Agostino, Simone
    Dipartimento di Chimica “Giacomo Ciamician”, Università; di Bologna, Bologna, Italy.
    Bergamini, Giacomo
    Dipartimento di Chimica “Giacomo Ciamician”, Università; di Bologna, Bologna, Italy.
    Grepioni, Fabrizia
    Dipartimento di Chimica “Giacomo Ciamician”, Università; di Bologna, Bologna, Italy.
    Braga, Dario
    Dipartimento di Chimica “Giacomo Ciamician”, Università; di Bologna, Bologna, Italy.
    Self-Assembly and Exfoliation of a Molecular Solid Based on Cooperative B-N and Hydrogen Bonds2018Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 18, nr 12, s. 7259-7263Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Herein we report that 4-pyridinylboronic acid (1) in the solid state self-assembles into tetrameric macrocycles via B-N bond formation. The tetramers are linked via O-H···O bonds resulting in a material that can be exfoliated via sonication to give thinner sheets as we demonstrate via Fourier transform infrared spectroscopy, transmission electron microscopy, selected area electron diffraction, and atomic force microscopy experiments. For comparison, the structure of the related compound 4-(pyridin-4-yl) phenylboronic acid (2) is also discussed

  • 32. Gamidi, R. K.
    et al.
    Rasmuson, Åke Christoffer
    University of Limerick.
    Estimation of melting temperature of molecular cocrystals using artificial neural network model2017Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 17, nr 1, s. 175-182Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    quantitative structure-activity relationship model has been constructed by artificial neural networks for estimation of melting temperature (T-m) of molecular cocrystals (CCs). On the basis of a literature, analysis using SciFinder and Cambridge Structural Database softwares, a database has been created of CCs for four active pharmaceutical ingredients, namely, caffeine, theophylline (THP), nicotinamide (NA), and isonicotinamide (INA). In total, of 61 CCs were included: 14-CAF, 9-THP, 29-INA, and 9-NA. A good correlation was obtained with ANNs to quantify the T-m of the CCs with respect to various coformers. The training process was completed with an average relative error of 2.38%, whereas the relative error for the validation set was 2.89%.

  • 33. George, Sumod
    et al.
    Goldberg, Israel
    Tel-Aviv University, Ramat-Aviv, School of Chemistry, Sackler Faculty of Exact.
    Self-assembly of supramolecular porphyrin arrays by hydrogen bonding: New Structures and Reflections2006Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 6, nr 3, s. 755-762Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This study relates to the self-assembly of the free-base 5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin (TCPP), six-coordinate manganese-5,10,15,20-tetrakis(4-carboxyphenyl)porphyrin with molecules of water or methanol as axial ligands [MnIII(H2O)2-TCPP or MnIII(CH3OH)2-TCPP, respectively], and manganese chloride-5,10,15,20-tetrakis(4-hydroxyphenyl)porphyrin [MnIII(Cl)-TOHPP] into multiporphyrin hydrogen-bonding "polymers". In the first case, the porphyrin units hydrogen bond directly to each other through their carboxylic acid functions. The two-dimensional (2D) square-grid polymeric arrays thus formed are sustained by characteristic intermolecular cyclic dimeric (COOH)2 hydrogen-bond synthons between a given porphyrin unit and four other neighboring species along the equatorial directions. They stack tightly one on top of the other in an offset manner along the normal direction, yielding channeled lattice architecture. In an aqueous basic environment insertion of MnIII into the porphyrin core involves deprotonation of one of the carboxylic groups, to balance the charge, and attraction of two water molecules as axial ligands. The MnIII(H2O)2-TCPP units hydrogen bond, however, directly to one another through their carboxylic/carboxylate functions in the equatorial plane in a catemeric (rather than cyclic dimeric) manner. The 2D networks that form in this case are interconnected in the normal direction by additional hydrogen bonds through the axial water ligands, yielding a three-dimensional (3D) hydrogen-bonding architecture. In a methanolic solution of H3PO4, the methanol molecules replace water as axial ligands to the metal ion. The phosphate anions balance the extra positive charge of the trivalent metal, and they act also as effective bridges between adjacent MnIII(CH3OH)2-TCPP moieties by interacting as proton acceptors with the peripheral carboxylic functions of four different porphyrins. This affords open square-grid-type layers with alternating porphyrin and phosphate components. The 2D arrays stack in an offset manner, interconnecting to one another through hydrogen bonds involving the methanol axial ligands. The Mn(Cl)-TOHPP building blocks arrange in a unique tetragonal structure around axes of 4-fold rotation and self-assemble through multiple O-HCl- attractions between neighboring units into a single-framework hydrogen-bonding polymer. The directional asymmetry introduced to them by the Cl-axial ligand, which is amplified by the preferred hydrogen-bonding scheme, induces the formation of a noncentrosymmetric crystal structure. The nanoporous nature of TCPP-based multiporphyrin assemblies and the chirality of the Mn(Cl)-TOHPP structure are highlighted.

  • 34. George, Sumod
    et al.
    Lipstman, Sophia
    Tel Aviv UniVersity, School of Chemistry, Sackler Faculty of Exact Sciences.
    Goldberg, Israel
    Tel Aviv UniVersity, School of Chemistry, Sackler.
    Porphyrin supramolecular solids assembled with the aid of lanthanide ions2006Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 6, nr 12, s. 2651-2654Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Reactions of free-base tetra(4-carboxyphenyl)porphyrin with lanthanide ions as Pr3+, Dy3+, and Nd3+ led to open metal-organic framework solids sustained by polynuclear metal-carboxylate clusters. Their three-dimensional structures are characterized by channel voids accessible to other guest components (e.g., water, small organics). Crystalline solids obtained by the hydrothermal synthesis with Dy3+ and Nd3+ reagents reveal remarkable stability and represent the first example of hybrid porphyrin-lanthanide single framework architectures.

  • 35.
    Godinho, Jose R. A.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för geologiska vetenskaper. Oak Ridge National Laboratory, United States.
    Putnis, Christine V.
    Piazolo, Sandra
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för geologiska vetenskaper. Macquarie University, Australia.
    Direct Observations of the Dissolution of Fluorite Surfaces with Different Orientations2014Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 14, nr 1, s. 69-77Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Atomic force microscopy has been used to observe the surface dynamics during dissolution of polished fluorite surfaces with different orientations. These surfaces, with an initially high density of atomic scale defects, showed fast changes during the first seconds in contact with a solution. Different types of structures developed on each surface, depending on its initial orientation and solution composition. These structures dissolved slower than the main surface persisting for at least 67.5 days of continuous dissolution. A new interpretation of traditional kinetic and thermodynamic models of dissolution applied to surfaces with a high density of steps is proposed to explain the observations. The new model includes the following: (a) fast initial dissolution at defect sites, (b) formation of a fluid boundary layer at the mineral solution interface enriched in the dissolving ions, and (c) precipitation of more stable fluorite structures nucleated at surface defects. This model highlights the importance of considering surface defects and crystal orientation for advancing our understanding of processes happening at the mineral solution interface and for developing more accurate kinetic dissolution and crystal growth models essential in Earth and material sciences.

  • 36.
    Gracin, Sandra
    et al.
    KTH, Tidigare Institutioner, Kemiteknik.
    Rasmuson, Åke C.
    KTH, Tidigare Institutioner, Kemiteknik.
    Polymorphism and Crystallization of p-Aminobenzoic Acid2004Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 4, nr 5, s. 1013-1023Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    p-Aminobenzoic acid (PABA) crystallizes in two different polymorphic forms: the alpha-polymorph, which is the commercially available form and appears as long, fibrous needles, and the beta-polymorph, which appears in the form of prisms. The thermodynamic stability and crystallization from different solvents have been studied experimentally. The system is found to be enantiotropic with a transition temperature of 25degreesC, below which the beta-form is the stable polymorph. The compound has been crystallized from 13 different solvents, either by slow cooling after which the product is allowed to mature in suspension, or by rapid cooling followed by immediate isolation. Needles were obtained from all solvents by both methods. In water and in ethyl acetate, at slow cooling below 20degreesC, the prismatic beta-form is obtained, however, often together with the needles. The beta-form crystals usually needed hours or days to grow at the very slow cooling used, while needles usually appeared in seconds. By careful control of supersaturation and temperature, cooling crystallization can be performed to produce the pure beta-form in water and in ethyl acetate. The influence of the solvent is explained by analysis of the crystal structures versus the possible interaction of the solvent molecules with the solute in solution. The alpha-form structure is governed by carboxylic acid dimers and is kinetically favored since it is believed that the corresponding dimers easily form in the solution, especially in less polar solvents.

  • 37.
    Gracin, Sandra
    et al.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Teknisk strömningslära.
    Uusi-Penttilä, Marketta
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Teknisk strömningslära.
    Rasmuson, Åke C.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Teknisk strömningslära.
    Influence of ultrasound on the nucleation of polymorphs of p-aminobenzoic acid2005Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 5, nr 5, s. 1787-1794Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    p-Aminobenzoic acid crystallizes in two different polymorphic forms: the alpha-form and the beta-form. The alpha-form crystals are needle-shaped, while the beta-form crystals have a more favorable prismatic shape. The system is enantiotropic with the transition temperature at approximately 25 degrees C. Below the transition temperature, the beta-form is the thermodynamically stable polymorph but can only be produced at very slow supersaturation generation either in water or in ethyl acetate. In the present work, the influence of ultrasound on the nucleation of p-aminobenzoic acid polymorphs has been investigated by use of several different sonication intensities and schemes. It is shown that sonication significantly reduces the induction time for nucleation. By using controlled sonication, we were able to more reproducibly crystallize the beta-form at more reasonable cooling rates. In addition, sonication is found to quite selectively favor the appearance of the beta-polymorph. It is even possible to produce the pure beta-form above the transition temperature where it is the metastable form and impossible to produce without sonication. The alpha-form structure is based on centro symmetric dimers formed by the association of carboxylic acid groups, while the beta-form contains four-membered hydrogen-bonded rings of alternating amino and carboxylic acid groups. It is suggested that ultrasound disturbs the building up of the dimers in the solution and thus favors the crystallization of the beta-polymorph.

  • 38.
    Guo, Peng
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK). Dalian Institute of Chemical Physics, Chinese Academy of Sciences, P. R. China.
    Yan, Nana
    Wang, Lei
    Zou, Xiaodong
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Database Mining of Zeolite Structures2017Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 17, nr 12, s. 6821-6835Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Zeolites are widely used in industrial applications such as ion exchange, gas separation and adsorption, and organic catalysis. In particular, in petroleum refining and petrochemical productions, zeolites are catalysts of utmost importance. In order to classify the known zeolites and correlate the structures with their unique properties, an online Database of Zeolite Structures was established in 1996 and continuously developed by Baerlocher and McCusker at ETH-Zurich. The database contains a lot of useful structural information such as unit cell dimensions, space group, atomic coordinates of tetrahedra (T) atoms, secondary building units (SBUs), composite building units (CBUs), natural tilings, simulated powder X-ray diffraction (PXRD), etc. It has served the zeolite community for more than 20 years and has made great contributions to the development of zeolites and zeolite-related fields. In this article, we take a further step to mine the intrinsic structural information on zeolites including characteristic unit cell dimensions, butterfly layers, zeolites containing the same building layers, ABC-6 zeolite family, and recently discovered embedded isoreticular RHO family. The database mining of zeolite structures will shed light not only on structural correlations of related existing zeolites but also the structure determination and the further prediction of novel zeolite structures based on the existing ones, which will facilitate the target synthesis of energetically feasible hypothetical zeolite structures.

  • 39.
    Gustafsson, Mikaela
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Su, Jie
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Yue, Huijuan
    Yao, Qingxia
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Zou, Xiaodong
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    A Family of Flexible Lanthanide Bipyridinedicarboxylate Metal-Organic Frameworks Showing Reversible Single-Crystal to Single-Crystal Transformations2012Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 12, nr 6, s. 3243-3249Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A family of flexible lanthanide metal-organic frameworks, [Ln(2)(bpydc)(3)(H2O)(3)]center dot nDMF (denoted as SUMOF-6-Ln; Ln = Nd, Sm, Eu, Gd, Tb, Dy, Ho, and Er, H(2)bpydc =2,2'-bipyridine-5,5'-dicarboxylic acid), was synthesized and characterized. SUMOF-6-Ln has a monoclinic space group P2(1)/c. The three-dimensional framework contains chains of LnO(n) (n = 7-8) polyhedra connected through the bpydc linkers forming 1D rhombic channels along the c-axis. SUMOF-6-Ln showed reversible breathing phenomenon upon desorption/adsorption of the solvent, with up to 27% changes of the unit cell dimensions and 23% changes of the unit cell volume. Single crystal X-ray diffraction (XRD) revealed that the desolvation and resolvation of SUMOF-6-Ln occurred via single-crystal to single-crystal transformations. The thermal behavior of SUMOF-6-Sm was also examined. SUMOF-6-Eu and SUMOF-6-Tb showed solid-state luminescent properties.

  • 40.
    Gustafsson, Stefan
    et al.
    Department of Applied Physics, Chalmers University of Technology.
    Fornara, Andrea
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik, Funktionella material, FNM.
    Petersson, Karolina
    Imego AB.
    Johansson, Christer
    Imego AB.
    Muhammed, Mamoun
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Materialfysik, Funktionella material, FNM.
    Olsson, Eva
    Department of Applied Physics, Chalmers University of Technology.
    Evolution of Structural and Magnetic Properties of Magnetite Nanoparticles for Biomedical Applications2010Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 10, nr 5, s. 2278-2284Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We have investigated the evolution of microstructure and magnetic properties of thermally blocked magnetite nanoparticles, aimed for immunoassay applications, during their synthesis. High-resolution transmission electron microscopy (HRTEM) investigations of the size, size distribution, morphology, and crystal structure of particles reveal that particles at an early stage of the reaction process are either single crystals or polycrystals containing planar faults and they grow via a combination of reactant (monomer) consumption and oriented attachment at specific crystallographic surfaces because of the strong dipolar character of the < 111 > surfaces of magnetite. At a later stage of the synthesis reaction, the magnetic attraction strives to align contacting particles with their < 111 > axis of easy magnetization in parallel and this may also be an active driving force for crystal growth. At latter stages, the crystal growth is dominated by Ostwald ripening leading to smoother crystalline particles with a mean diameter of 16.7 +/- 3.5 nm and a narrow size distribution. The magnetic properties of the particles measured using static and dynamic magnetic fields are consistent with the evolution of particle size and structure and show the transition from superparamagnetic to thermally blocked behavior needed for magnetic relaxation-based immunoassay applications.

  • 41. Han, Lei
    et al.
    Qin, Lan
    Yan, Xiao-Zhi
    Xu, Lan-Ping
    Sun, Junliang
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Yu, Lei
    Chen, Hong-Bing
    Zou, Xiaodong
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Two Isomeric Magnesium Metal-Organic Frameworks with [24-MC-6] Metallacrown Cluster2013Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 13, nr 5, s. 1807-1811Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Two novel Mg-based metal-organic framework isomers with the formula [Mg-2(HCO2)(2)(NH2-BDC)-(DMF)(2)](n) (NH2-BDC = 2-amino-1,4-benzenedicarboxylate) have been synthesized based on a 6-connected [24-MC-6] metallacrown secondary building unit (SBU), which display a two-dimensional (2D) 3(6) net (1) and three-dimensional primitive rhombohedral net (2) derived from a different extended orientation of SBU, respectively. The 2D framework of 1 exhibits relevant thermal stability, solvents stability, high CO2 adsorption, and strong luminescent properties.

  • 42. Heffernan, C.
    et al.
    Ukrainczyk, M.
    Zeglinski, J.
    Hodnett, B. K.
    Rasmuson, Åke Christoffer
    Synthesis and Solid State Pharmaceutical Centre, Department of Chemical Sciences, Bernal Institute, University of Limerick.
    Influence of Structurally Related Impurities on the Crystal Nucleation of Curcumin2018Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 18, nr 8, s. 4715-4723Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this work, the influence of the structurally related impurities, demethoxycurcumin (DMC) and bisde-methoxycurcumin (BDMC) on the primary nucleation of curcumin (CUR) has been investigated in propan-2-ol. The induction time for nucleation was measured at different CUR driving forces and impurity concentrations 0.10 mmol.dm(-3), 0.30 mmol.dm(-3), and 0.60 mmol.dm(-3) and the results are analyzed by the classical nucleation theory (CNT). The nucleation rate for the impure systems was noticeably lower than the nucleation rate of the pure system, and the times of growth to visibility were much longer for the impure systems. The pre-exponential factors are clearly lower for the impure system compared to the pure CUR system, while the increase in the solid-liquid interfacial energy is small. Density functional theory and metadynamic molecular modeling reveal that the 1:1 bonding between CUR and an impurity molecule is stronger than to another CUR molecule, thus suggesting that the developing CUR nucleus has to overcome a certain energy barrier in order to remove the impurity molecules from their surface, which may explain why nucleation of CUR is more difficult in the presence of the structurally related impurities, DMC and BDMC.

  • 43. Hu, Y.
    et al.
    Erxleben, A.
    Hodnett, B. K.
    Li, B.
    McArdle, P.
    Rasmuson, Åke Christoffer
    Materials and Surface Science Institute, Department of Chemical and Environmental Sciences, University of Limerick.
    Ryder, A. G.
    Solid-state transformations of sulfathiazole polymorphs: The effects of milling and humidity2013Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 13, nr 8, s. 3404-3413Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The effect of milling on the transitions of sulfathiazole polymorphs in the absence and presence of solvent and excipients was monitored by X-ray powder diffraction (XRPD), attenuated total reflectance infrared (ATR-IR), and near-infrared (NIR) spectroscopy. Sulfathiazole forms FII-FV undergo a transformation toward the metastable FI, which involves an intermediate amorphous stage upon milling at ambient temperature. Milling the commercial form (FC) with catalytic amounts of solvent converts it to pure FIV or to mixtures of FI and FIV depending on the solvent used. Pure FIV can be easily prepared from FC by this method. The physical stability of nonmechanically activated pure sulfathiazole forms in the presence of different levels of relative humidity (RH) was also investigated. At low RH, all sulfathiazole forms are kinetically stable, but at RH levels above 70% FII, FC and FIV remain stable, while FI and FV transform to mixtures of FII and FIV without any apparent change in the external form of the crystals. Comilling FC with a range of excipients gave results that depended on the excipient used, and comilling with cellulose gave samples that had an amorphous content that was stable at 10% RH for at least nine months at ambient temperature.

  • 44.
    Huang, Shiliang
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK). China Academy of Engineering Physics, China.
    Yue, Huijuan
    Chen, Yanping
    Liu, Yu
    Guan, Yuxiang
    Zou, Xiaodong
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Sun, Junliang
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK). Peking University, China.
    Three-Dimensional Open-Framework Germanate Built from a Novel Ge-13 Cluster and Containing Two Types of Chiral Layers2018Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 18, nr 2, s. 928-933Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A new open-framework germanate [Ge15O30(OH)(4)]center dot 2(H(2)tren), denoted SU-69, was synthesized under hydrothermal conditions with tris(2-aminoethyl)-amine (tren) as a structure directing agent (SDA). SU-69 crystallizes in a monoclinic space group (C2/c, No. 15) with a = 20.2656(7) angstrom, b = 11.6250(4) angstrom, c = 18.5602(10) angstrom, and beta = 90.528(4)degrees. The framework of SU-69 is built from a novel Ge13O27(OH)(2) (Ge-13) cluster with two additional GeO3(OH) tetrahedra. Two types of chiral 3,6-net building layers are found in the framework, which alternately stack and connect to form a three-dimensional achiral framework with a two-dimensional 10 x 12-ring channel system. The SDA molecules interact with the framework via H-bonds. The thermal stability of as-synthesized SU-69 has also been investigated.

  • 45.
    Inge, A. Ken
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Christensen, Kirsten E.
    Willhammar, Tom
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Zou, Xiaodong
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    A Germanate with a Collapsible Open-Framework2016Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 16, nr 12, s. 6967-6973Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A novel open-framework germanate, vertical bar NC2H8 vertical bar vertical bar N2C6H18 vertical bar, [Ge7O14.5F2].4H(2)O denoted SU-65 (SU = Stockholm University), with 24-ring channels and a very low framework density of 8.9 Ge atoms per 1000 angstrom(3) was synthesized under hydro-solvothermal conditions. The framework of SU-65 is built of 5-connected Ge-7 clusters decorating the fee net and is a framework orientation isomer to ASU-16. Half of the 8- and 12-rings in ASU-16 are instead 10-rings in SU-65 due to the different orientations of half of the clusters in the crystal structure. Flexibility of the frameworks is also influenced by the orientation of the clusters. The unique unit cell angle in SU-65 changes upon heating, unlike ASU-16 which only undergoes changes in unit cell lengths. SU-65 undergoes significant structural changes at 180 degrees C in a vacuum, forming SU-65ht. The crystal structure of SU-65ht was investigated by rotation electron diffraction, X-ray powder diffraction, and infrared spectroscopy. Through these techniques it was deduced that SU-65ht has similar clusters, symmetry, and topology as SU-65, but one of the unit cell lengths is shortened by approximately 5 A. This corresponds to a 22% decrease in unit cell volume.

  • 46.
    Inge, Andrew Kentaro
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Huang, Shiliang
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Chen, Hong
    Moraga, Francisca
    Sun, Junliang
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Zou, Xiaodong
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    The Structure of a Complex Open-framework Germanate Obtained by Combining Powder Charge-Flipping and Simulated Annealing2012Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 12, nr 10, s. 4853-4860Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A novel open-framework germanate SU-74 containing intersecting 10- and 12-ring channels was prepared by hydrothermal synthesis using 2-methylpentamethylenediamine (MPMD) or 1-(2-aminoethyl)piperazine (AEP) as the organic structure directing agent (SDA). The framework structure of SU-74-MPMD was solved from X-ray powder diffraction (XRPD) data using powder charge-flipping (pCF). The guest species H2MPMD2+, NH4+ cations and water molecules were located in the voids using real-space simulated annealing. SU-74-MPMD contains 51 non-hydrogen atoms in its asymmetric unit and is one of the most complex framework structures solved by XRPD. The structure of SU-74-AEP was solved by single crystal synchrotron X-ray diffraction. SU-74-MPMD and SU-74-AEP have the same framework structure. The location of the NH4+ cations in both structures is similar, while the positions of the SDAs in the pores are different. SU-74 follows the fcu-11-P21/c net. The underlying topology of SU-74 is compared to those of other Ge10 structures containing additional GeO4 tetrahedra. The presence of additional tetrahedra can significantly affect the framework topology through the addition of edges between the Ge10 nodes.

  • 47.
    Inge, Andrew Kentaro
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Peskov, Maxim V.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Sun, Junliang
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Zou, Xiaodong
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    SU-62: Synthesis and Structure Investigation of a Germanate with a Novel Three-Dimensional Net and Interconnected 10- and 14-Ring Channels2012Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 12, nr 1, s. 369-375Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A novel 3D open-framework germanate, vertical bar N(2)C(4)H(14)vertical bar(4) [Ge(20)O(41)(OH)(6)]center dot 3H(2)O (SU-62), was prepared from hydrothermal synthesis using 1,4-diaminobutane as the organic structure directing agent (SDA). The crystal structure was solved by single crystal X-ray diffraction. The framework is built from Ge(10)(O,OH)(27) (Ge(10)) secondary building units and exhibits an irregular three-dimensional channel system encircled by 10- and 14-rings. The framework of SU-62 has an underlying topology that follows a novel five-coordinated svh-5-I4(1)/amd net, while the pores follow the tsi net. The thermal behavior of SU-62 was studied by thermogravimetric (TG) analysis and in situ X-ray diffraction (XRPD). Crystallographic data: orthorhombic, space group Fdd2, unit cell parameters a = 15.297(3) angstrom, b = 53.58(1) angstrom, c = 14.422(3) angstrom, V = 11821(4) angstrom(3), Z = 8.

  • 48. Jayakumar, O. D.
    et al.
    Sudakar, C.
    Persson, Clas
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Tillämpad materialfysik.
    Sudarsan, V.
    Sakuntala, T.
    Naik, R.
    Tyagi, A. K.
    1D Morphology Stabilization and Enhanced Magnetic Properties of Co: ZnO Nanostructures on Codoping with Li: A Template-Free Synthesis2009Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 9, nr 10, s. 4450-4455Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    ID natiostructures of Zn1-xCoxO (x = 0, 0.03 and 0.05) and Co and Li codoped ZnO (Zn0.85Li0.10Co0.05O) were prepared by a soft chemical method. We report a very interesting observation of morphological control and transformation of ZnO nanorods to spherical particles induced by Co substitution. It is also remarkable to note that the morphology completely reverts back to rod shape by Li incorporation. In addition to this unusual observation, the Li incorporation enhances the room-temperature ferromagnetic (RTFM) properties. These experimental observations are well-supported by theory work as well. These results are significant, as the I D RTFM will have implications in spintronic devices.

  • 49.
    Jia, Lijun
    et al.
    University of Limerick, Ireland.
    Svärd, Michael
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Teknisk strömningslära.
    Rasmuson, Åke C.
    KTH, Skolan för kemivetenskap (CHE), Kemiteknik, Teknisk strömningslära. University of Limerick, Ireland.
    Crystal Growth of Salicylic Acid in Organic Solvents2017Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 17, nr 6, s. 2964-2974Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The crystal growth rate of salicylic acid has been determined by seeded isothermal desupersaturation experiments in different organic solvents (methanol, acetone, ethyl acetate, and acetonitrile) and at different temperatures (10, 15, 20, and 25 °C). In situ ATR-FTIR spectroscopy and principal component analysis (PCA) were employed for the determination of solution concentration. Activity coefficient ratios are approximately accounted for in the driving force determination. The results show that the dependence of the growth rate on the solvent at equal driving force varies with temperature; e.g., at 25 °C, the growth rate is highest in ethyl acetate and lowest in acetonitrile, while at 15 °C the growth rate is highest in acetonitrile. The growth rate data are further examined within the Burton Cabrera Franck (BCF) and the Birth and Spread (B+S) theories, and the results point to the importance of the surface diffusion step. Interfacial energies determined by fitting the B+S model to the growth rate data are well-correlated to interfacial energies previously determined from primary nucleation data.

  • 50.
    Jokubavicius, Valdas
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Yazdi, G. Reza
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Liljedahl, Rickard
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Ivanov, Ivan Gueorguiev
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Yakimova, Rositsa
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Syväjärvi, Mikael
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Halvledarmaterial. Linköpings universitet, Tekniska högskolan.
    Lateral Enlargement Growth Mechanism of 3C-SiC on Off-Oriented 4H-SiC Substrates2014Ingår i: Crystal Growth & Design, ISSN 1528-7483, E-ISSN 1528-7505, Vol. 14, nr 12, s. 6514-6520Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    We introduce a 3C-SiC growth concept on off-oriented 4H-SiC substrates using a sublimation epitaxial method. A growth model of 3C-SiC layer development via a controlled cubic polytype nucleation on in situ formed on-axis area followed by a lateral enlargement of 3C-SiC domains along the step-flow direction is outlined. Growth process stability and reproducibility of high crystalline quality material are demonstrated in a series of 3C-SiC samples with a thickness of about 1 mm. The average values of full width at half-maximum of ω rocking curves on these samples vary from 34 to 48 arcsec indicating high crystalline quality compared to values found in the literature. The low temperature photoluminescence measurements also confirm a high crystalline quality of 3C-SiC and indicate that the residual nitrogen concentration is about 1–2 × 1016 cm–3. Such a 3C-SiC growth concept may be applied to produce substrates for homoepitaxial 3C-SiC growth or seeds which could be explored in bulk growth of 3C-SiC.

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