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Crystal growth & design
American Chemical Society
Crystal growth & design

American Chemical Society

1528-7483

Crystal growth & design/Journal Crystal growth & designICCCRAHCISCIISTP
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    Crystallizing the Role of Solid-State Form in Drug Delivery

    Taylor, Lynne S.Braun, Doris E.Tajber, LidiaSteed, Jonathan W....
    3页
      原文链接:
    • NSTL
    • Amer Chemical Soc

    Vanadate Encapsulated Polyoxoborate Framework with [V12B18] Clusters: An Efficient Bifunctional Electrocatalyst for Oxygen and Hydrogen Evolution Reactions

    Rom, TanmayBiswas, RathindranathHaldar, Krishna KantaSaha, Uttam...
    7页
    查看更多>>摘要：Widespread contemporary attention has grown over the years in the search for a new functional and robust inorganic framework system with the advent of exciting applications. Herein, a facile strategy has been demonstrated for developing noble-metal-free bifunctional electrocatalysts by successfully preparing a polyoxovanadoborate framework compound, i.e., [Na-10(H2O)(18)][(VO)(12)(mu(3)-OH)(6)(B3O7)(6)]center dot 5H(2)O, i.e., NVBO-I. Anionic vanadoborate clusters are interconnected through a cationic sodium aquated chain to form a three-dimensional framework structure. The compound exhibits remarkable bifunctional activity for oxygen and hydrogen evolution reactions over many well-engineered and state-of-art electrocatalysts under a similar catalytic environment.
      原文链接:
    • NSTL
    • Amer Chemical Soc

    Behavior of All Chiral Standard Amino Acids for Chiral Symmetry Breaking of p-Anisoin

    Miyazaki, NorikaSanada, KazutakaNakamura, TakumiWashio, Aoi...
    7页
    查看更多>>摘要：The asymmetric amplification of p-anisoin was studied by attrition-enhanced deracemization in the presence of chiral standard amino acids. In this reaction, p-anisoin crystallized as a conglomerate, and deracemization under basic conditions was efficiently performed in 99% ee by Viedma ripening. Although the handedness of the enantioselective crystallization cannot be controlled by spontaneous crystallization, it could be governed by the coexistence of a catalytic amount of 16 chiral amino acids except cysteine, serine, and threonine. L-Amino acids tilted the handedness of enantiomer crystals to (R)-anisoin, while D-amino acids tilted it toward (S)-isomer crystals. It was clarified that this is due to the asymmetric transformation of p-anisoin in the mother liquor by the enantiomeric amino acids. The same slight asymmetric transformation in the solution phase was observed in alpha-hydroxyketones such as acetoin. Though the Soai reaction for an autocatalytic and asymmetric amplification system in the presence of a variety of chiral sources is famous, the crystallization-induced dynamic deracemization of p-anisoin provides the first chirality control system to be tilted by the enantioselective crystallization derived from many chiral additives.
      原文链接:
    • NSTL
    • Amer Chemical Soc

    In Situ Reaction and Coordination Site Regulation to Form Binuclear Dysprosium Complexes with Different Connections and Magnetic Properties

    Wang, Hai-LingAi, Ju -FenWang, Yu-FengYu, Shui...
    9页
    查看更多>>摘要：How to construct and control multinuclear dysprosium clusters with excellent single-molecule magnet (SMM) properties have been a great concern and challenge. Herein, we obtained two pyridine monoacylhydrazone ligands that are isomers of each other by a solvothermal in situ reaction, and the position of the N coordination site on the pyridine ring was controlled to achieve two binuclear dysprosium-based complexes with different SMM performance and cluster core connections. Specifically, 2-pyridinecarboxylhydrazide and 1-methyl-1H-imidazole-2-carbaldehyde undergo an in situ Schiff base reaction at 80 degrees C solvothermal conditions and coordinate with Dy(NO3)(3)middot6H(2)O to obtain a binuclear dysprosium complex [Dy-2(L-1)(2)(NO3)(4)(H2O)](HL1)middot(H2O)(2)(CH3CN)(2) (1) with a Dy2O2 cluster nucleus. In addition, the mononuclear dysprosium complex [Dy(L-2)(NO3)(2)(H2O)(2)]middotCH(3)CN (2) and binuclear dysprosium complex [Dy(L-2)(2)(NO3)](2)middot4CH(3)CN (3) were obtained by changing 2-pyridinecarboxylhydrazide to 3-pyridinecarboxylhydrazide and adjusting the solvent ratio of the reaction system. In the structure of binuclear dysprosium complex 3, DymiddotmiddotmiddotDy is not bridged by O atoms and has a long distance. Magnetic studies show that complexes 1-3 all exhibit field-induced SMM behaviors. Under the external field, the inversion energy barriers and relaxation times of complexes 1-3 are U-eff = 22.40(6) K and tau(0) = 7.33(1) x 10(-5) s (1), U-eff = 16.38(1) K and tau(0) = 1.25(6) x 10(-4) s (2), and U-eff = 59.25(9) K and tau(0) = 6.30(1) x 10(-5) s (3), respectively. This work demonstrates that the design of the coordination sites for organic ligands is an effective strategy to tune the SMM properties of the polynuclear dysprosium complexes. It also provides a vivid example for the directional construction of multinuclear dysprosium complexes with SMM behaviors by in situ reactions in a black-box system.
      原文链接:
    • NSTL
    • Amer Chemical Soc

    Water-Sensitive Mixed-Phase PEA(6)SnI(8) Perovskite Derivative Single Crystal for Humidity Detection

    Ju, YangyangPeng, JiaChen, YuHuang, Sheng...
    7页
    查看更多>>摘要：Due to the sensitive photoelectric response upon an external humidity stimulus, metal halide perovskites have been demonstrated as emerging candidates for trace water detection. Here, we report an eco-friendly zero-dimensional PEA(6)SnI(8) single crystal for efficient humidity detection, which can exhibit luminescent chromism with an instant trace water response as low as 0.02 ppm. The characterizations and spectroscopic measurements demontrated that the PEA(6)SnI(8) single crystal has mixed phases with a triclinic phase in the surface and a hexagonal phase in the interior. By measuring the water-induced photoluminesence change during the transformation from triclinic PEA(6)SnI(8) phase to PEA(2)SnI(4), the environmental humidity can be determined. Furthermore, the as-formed PEA(2)SnI(4) in the surface of the mixed-phase PEA(6)SnI(8) crystal can be removed by dichloromethane (DCM) washing and the pristine mixed-phase crystallographic structure of PEA(6)SnI(8) crystal can recover through a facile phase transformation. The rapid and reversible color change of a mixed-phase PEA(6)SnI(8) crystal upon water and DCM process provides an advanced functional material for luminescent humidity sensors with an extremely low detection limit.
      原文链接:
    • NSTL
    • Amer Chemical Soc

    Molybdenum and Tungsten Di-sulfides: First Principles Investigation of Adatom Attachment and Diffusion on c-plane Alpha Sapphire and Correlation with Growth

    Lalithambika, AnjaliKumar, V. KranthiJain, ManishRaghavan, Srinivasan...
    13页
    查看更多>>摘要：Understanding the underlying mechanism to growth of a material greatly assists control over its synthesis. In this investigation, we employ density functional theory to calculate the desorption and diffusion energy barriers to growth of MoS2 and WS2 from a M-C-O-H-S system on c-plane alpha sapphire, a commonly used substrate. We then perform experiments and use these numbers within a nucleation theory framework to explain growth characteristics. Nucleation rates, densities, and step velocities are predicted and analyzed. In particular, differences between MoS2 and WS2 growth -larger nucleation densities and small island sizes in WS2 compared to MoS2-are explained and correlated to the differences between energy barriers to desorption and diffusion of W and Mo.
      原文链接:
    • NSTL
    • Amer Chemical Soc

    Use of Wet Milling Combined with Temperature Cycling to Minimize Crystal Agglomeration in a Sequential Antisolvent-Cooling Crystallization

    Sun, ZhuangQuon, Justin L.Papageorgiou, Charles D.Benyahia, Brahim...
    15页
    查看更多>>摘要：The objective of the research was to improve the process design of a combined antisolvent-cooling crystallization to reduce the degree of agglomeration of a real active pharmaceutical ingredient product, which was manufactured using a crystallization stage employing a methanol/water solvent system. Knowledge was gained from the use of process analytical technology (PAT) tools to monitor the process variables, allowing particle size, degree of agglomeration, solute concentration, and supersaturation to be tracked throughout the process. Based on knowledge of the solubility behavior and interpretation of the PAT histories, changes were made to the sequences of antisolvent addition and cooling within the crystallization process to reduce agglomeration in the final product. Different seed loadings and seeding addition points were also investigated to maintain operation within lower supersaturation regions of the phase diagram to limit agglomeration and avoid an undesired polymorphic transformation to an unstable form. The improved sequences of operations and seeding conditions did not provide sufficient improvement in the product quality and so were augmented by applying wet milling for further deagglomeration followed by temperature cycling to remove fine particles generated during milling. Open-loop heating and cooling cycles produced some limited improvements, whereas dosed-loop direct nucleation control methods using FBRM as a feedback sensor for particle counts per second were much more successful at producing high-quality crystals of the desired polymorphic form. The work shows that understanding the trajectory of the process through the phase diagram to follow appropriate supersaturation profiles gives improved control of the various kinetic mechanisms and can be used to improve the quality of the final product.
      原文链接:
    • NSTL
    • Amer Chemical Soc

    Crystalline Covalent Organic Frameworks Based on Mixed Metallo- and Tetrahydroporphyrin Monomers for Use as Efficient Photocatalysts in Dye Pollutant Removal

    Liu, ChenxiChen, MinghuiLi, HongruiShi, Quan...
    12页
    查看更多>>摘要：Unique features, including a high specific surface area, great stability, and crystallinity, make covalent organic frameworks (COFs) intriguing sorbents and catalysts in light-driven water pollutant degradation. Inspired by the light absorption capability of porphyrin derivatives and the carrier separation ability of a donor-acceptor (D-A) configuration, we constructed two-dimensional porphyrin donor-based D-A COFs: COF-HTBD involving only tetrahydroporphyrins and COF-HMTBD (M = Co, Fe, Cu) involving both tetrahydro- and metalloporphyrins via a mixed porphyrin monomer strategy. The monomer 2,1,3-benzothiadiazole-4,7dicarboxaldehyde (BD) is incorporated as an electron accepting moiety. Interestingly, COF-HTBD, COF-HCuTBD, and COF-HFeTBD exhibit staggered stacking, while the stacking model of COF-HCoTBD transforms from staggered to eclipsed. Notably, COF-HFeTBD demonstrates excellent activities and stabilities toward visible light-driven photocatalytic rhodamine B (RhB) degradation in aqueous solutions with H2O2 present (100% removal in 3 h). Overall, this work provides an interesting strategy for the construction of D-A-type porphyrin COFs for dye pollutant removal.
      原文链接:
    • NSTL
    • Amer Chemical Soc

    Polymorphism in 9-[(9H-Fluoren-9-ylidene)methyl]phenanthrene

    Roth, Alexander D.Thamattoor, Dasan M.
    11页
    查看更多>>摘要：Three polymorphs of the hydrocarbon 9-[(9H-fluoren-9-ylidene)methyl]phenanthrene have been isolated and characterized by single-crystal X-ray crystallography. Of these, one form displays conformational polymorphism with respect to the other two, a phenomenon that is less common in simple hydrocarbons. The 5 alpha form, obtained from an earlier fraction following purification by column chromatography using hexanes as the eluent, belonged to the monoclinic crystal system (space group P2(1)/n) and displayed a twist angle of similar to 75 degrees between the phenanthrene and dibenzofulvene planes. Polymorph 5 beta(mc), which was isolated from a later fraction, also from hexanes, was solved in the monoclinic space group P2(1)/c and found to have a narrower interplanar angle of similar to 55 degrees. Curiously, when the synthesis of the title compound was repeated, the 5 alpha form could not be detected. Instead, the 5 beta form was obtained but in two different modifications with virtually equivalent molecular structures, one as the monoclinic polymorph 5 beta(mc) mentioned above and the other as a new polymorph 5 beta(or) that was solved in the orthorhombic space group Pbca. Differential scanning calorimetry experiments indicated that some of the column fractions (again using hexanes as the eluent) contained both 5 beta(mc) and 5 beta(or) indicating concomitant crystallization. Several attempts at separately growing the 5 alpha form proved unsuccessful with either 5 beta(mc) or 5 beta(or) being formed exclusively depending on the conditions. All three polymorphs show a common, and comparable, intramolecular C-H/pi interaction, but major differences are apparent both in the number and nature of intermolecular contacts made by each form. Quantum chemical calculations on 5 alpha and 5 beta(mc) (chosen as a representative of the beta form) were performed using three different model chemistries, PBE0/6-311+G(d,p), B2PLYP/def2-TZVP, and DLPNO-CCSD(T)/def2-TZVP. These calculations show that the two conformers are close in energy with the single-point energies of 5 beta(mc) slightly lower than that of 5 alpha by about 1.7 to 2.6 kcal/mol. Furthermore, optimization of 5 alpha and 5 beta(mc) (B2PLYP-D3BJ/def2-TZVP or PBE0-D3BJ/6-311+G(d,p)) led to energetically degenerate structures with geometries that were closer to the latter. A PBE0-D3BJ/6-311+G(d,p) relaxed potential energy scan about the sigma bond connecting the two ring planes revealed four maxima and four minima. A rotational barrier of 8-9 kcal/mol was estimated for the interconversion of the two conformers.
      原文链接:
    • NSTL
    • Amer Chemical Soc

    Short-Range Mechanisms in the Creation of a ZnO/InGaAs Interface

    Ciatto, GianlucaSkopin, Evgeniy V.Richard, Marie-IngridFong, Dillon D....
    9页
    查看更多>>摘要：We perform quantitative analysis of the X-ray absorption data taken in situ during the earliest cycles of the ZnO atomic layer deposition on atomically flat InGaAs (001) surfaces. As deposition progresses, we observe a transition from an amorphous structure to a nanocrystalline one. The former retains much of the characteristics of a ZnO crystal in the Zn coordination shell, while the latter shows atomic ordering up to at least the third neighbor shell of Zn atoms, despite the absence of Bragg X-ray diffraction peaks. We show that the different chemical preparation of the substrate surface affects the ZnO local structure and that, counterintuitively, a stronger short-range order is obtained in the nanostructures characterized by lower local order at the interface. We propose a model that accounts for these findings.
      原文链接:
    • NSTL
    • Amer Chemical Soc