Showing papers in "Crystal Growth & Design in 2008"
TL;DR: In this article, the authors used fingerprint plots of Hirshfeld surfaces to locate and analyze the deficiencies in various methodologies employed in the determination of the relative energies of five polymorphs of 1,8-dihydroxyanthraquinone.
Abstract: Fingerprint plots of Hirshfeld surfaces were used to locate and analyze the deficiencies in various methodologies employed in the determination of the relative energies of five polymorphs of 1,8-dihydroxyanthraquinone. Nine crystallographically independent molecules were characterized by X-ray crystallography and Hirshfeld surfaces were derived from the X-ray structures. The space groups and number of independent molecules (Z′) for each of the polymorphs (1−5) is as follows: (1) P41 (or P43),Z′ = 1; (2) Pca21, Z′ = 2; (3) P1, Z′ = 4; (4) P21/n, Z′ = 1; (5) P41212 (or P43212), Z′ = 0.5. Form 1 is the most thermodynamically stable among the reproducible structures, as established by competitive solubility tests, followed by 2 and then 4. The unrestrained structures of the five polymorphs were computed using the CVFF and COMPASS force fields as well as with the density functional code, SIESTA.
450 citations
TL;DR: In this paper, the authors evaluate the hierarchy of supramolecular heterosynthons that involve two of the most relevant functional groups in the context of active pharmaceutical ingredients, carboxylic acids and alcohols, in competitive environments.
Abstract: A Cambridge Structural Database (CSD) analysis was conducted in order to evaluate the hierarchy of supramolecular heterosynthons that involve two of the most relevant functional groups in the context of active pharmaceutical ingredients, carboxylic acids and alcohols, in competitive environments. The study revealed that 34% of the 5690 molecular carboxylic acid entries and 26% of the 25 035 molecular alcohol entries form supramolecular homosynthons, whereas the remaining entries form supramolecular heterosynthons with other functional groups, in particular Narom, CONH2, C−O−C, C═O, and chloride anions. Further refinement of this raw data revealed the following: 98% occurrence of the COOH···Narom supramolecular heterosynthon in the 126 crystal structures that contain acid and pyridine moieties in the absence of other hydrogen bond donors or acceptors; and 78% occurrence of the OH···Narom supramolecular heterosynthon in 228 crystal structures that contain hydroxyl and pyridine moieties (excluding intramolec...
402 citations
TL;DR: In this paper, a low-to medium-throughput approach, encompassing both a melt and solution crystallization step as a route to the identification of co-crystals, was reported.
Abstract: Co-crystal screening is routinely undertaken using high-throughput solution growth. We report a low- to medium-throughput approach, encompassing both a melt and solution crystallization step as a route to the identification of co-crystals. Prior to solution studies, a melt growth step was included utilizing the Kofler mixed fusion method. This method allowed elucidation of the thermodynamic landscape within the binary phase diagram and was found to increase overall screening efficiency. The pharmaceutically acceptable adduct nicotinamide was selected and screened against a small set of active pharmaceutical ingredients (APIs) (ibuprofen (both the racemic compound (R/S) and S-enantiomer), fenbufen, flurbiprofen (R/S), ketoprofen (R/S), paracetamol, piracetam, and salicylic acid) as part of a larger systematic study of synthon stability. From the screen, three new co-crystal systems have been identified (ibuprofen (R/S and S) and salicylic acid) and their crystal structures determined. Because of poor crystal growth synchrotron radiation was required for structure solution of the S-ibuprofen nicotinamide co-crystal. Two further potential systems have also been discovered (fenbufen and flurbiprofen), but crystals suitable for structure determination have yet to be obtained. A greater ability to control crystallization kinetics is required to yield phase-pure single-crystalline material for full verification of this crystal engineering strategy.
299 citations
TL;DR: Uniform single-crystalline CeO2 nano-octahedrons and nanorods were synthesized by a facile hydrothermal synthesis process only using Ce(NO3)3·6H2O as cerium resource and Na3PO4·6HO as mineralizer.
Abstract: Uniform single-crystalline CeO2 nano-octahedrons and nanorods were synthesized by a facile hydrothermal synthesis process only using Ce(NO3)3·6H2O as cerium resource and Na3PO4·6H2O as mineralizer,...
295 citations
TL;DR: In this article, a 1:1 cocrystal of caffeine and methyl gallate was formed by suspending powders of the two pure compounds in ethanol, and the tabletability of the cocrestal was excellent over the entire pressure range.
Abstract: By the formation of a 1:1 cocrystal of caffeine and methyl gallate, we demonstrated that powder compaction properties could be profoundly improved. The selection criterion for cocrystal exhibiting superior compaction properties was the presence of slip planes in crystal structure. Bulk cocrystal was prepared by suspending powders of the two pure compounds in ethanol. Fine powders of similar particle size distribution were compressed. Within the whole range of compaction pressure, the tablet tensile strength of methyl gallate was very poor ( 180 MPa, severe lamination of caffeine tablets suddenly occurred. Tablet tensile strength dropped sharply at >240 MPa. In contrast, the tabletability of the cocrystal was excellent over the entire pressure range. Tablet tensile strength of the cocrystal was ∼2 times that of caffeine at <200 MPa, and the ratio gradually increased...
292 citations
TL;DR: Cocrystals of carbamazepine with nicotinamide and saccharin are shown to be polymorphic and the unique feature of CBZ-SAC II, a new polymorph, is the formation of a heterosynthon between the carbazepine and sacCharin.
Abstract: Cocrystals of carbamazepine with nicotinamide and saccharin are shown to be polymorphic. Two polymorphs of carbamazepine-nicotinamide (CBZ-NCT) cocrystals and two polymorphs of carbamazepine-saccharin (CBZ-SAC) cocrystals were grown from solution in the presence of polymer heteronuclei. The two CBZ-NCT polymorphs, CBZ-NCT I and a polymer nucleated (PN) form of CBZ-NCT, were characterized by Raman spectroscopy and powder X-ray diffraction. CBZ-SAC II, a new polymorph, was found to be in the monoclinic space group C2/c with a = 35.72 A, b = 6.84 A, c = 16.11 A, and β = 98.03°. The unique feature of CBZ-SAC II is the formation of a heterosynthon between the carbamazepine and saccharin. These results are notable because CBZ-NCT and CBZ-SAC are among the most widely studied pharmaceutical cocrystals.
246 citations
TL;DR: In this paper, a template-directed deposition and in situ template-sacrificial dissolution method was developed in pure water by using SiO2 microspheres as templates and TiF4 as the precursor at 60 °C.
Abstract: A simple one-step template method for the fabrication of crystalline titania (TiO2) hollow microspheres, based on template-directed deposition and in situ template-sacrificial dissolution, is developed in pure water by using SiO2 microspheres as templates and TiF4 as the precursor at 60 °C. The wall thickness and size of the TiO2 hollow spheres can be controlled by adjusting the concentration of the precursor TiF4 and the size of the SiO2 spheres, respectively. The prepared TiO2 hollow spheres exhibit hierarchically nanoporous structures and a high photocatalytic activity. This hierarchically micromeso-macrostructured TiO2 hollow microspheres should find various potential applications in photocatalysis, catalysis, solar cells, and separation and purification processes.
243 citations
TL;DR: In this paper, a template-free solvothermal route was used to synthesize uniform-sized, monodisperse, and single-crystal magnetite hollow spheres with a diameter of 200−300 nm and a shell thickness of ∼50 nm.
Abstract: Uniform-sized, monodisperse, and single-crystal magnetite hollow spheres with a diameter of 200−300 nm and a shell thickness of ∼50 nm have been successfully synthesized in high yield using a template-free solvothermal route. The reaction duration and the ethylenediamine amount are shown to play important roles in the formation of the magnetite hollow spheres. X-ray diffraction, X-ray photoelectron spectroscopy, Fourier tranform IR, scanning electron microscopy, transmission electron microscopy (TEM), and high-resolution TEM were used to characterize the products. The results show that the prepared single-crystalline hollow spheres are composed of well-aligned magnetite and have a cubic structure. The magnetite hollow spheres show a high saturation magnetization of ca. 68 emu/g, a remnant magnetization of ca. 13 emu/g, and a coercivity of ca. 94 Oe at room temperature. A possible mechanism for the formation of magnetite hollow spherical structures is proposed based on the experimental observations. The pr...
233 citations
TL;DR: In this article, nearly monodisperse Pd nanocubes with controllable sizes were synthesized through a seed-mediated growth approach, where the morphology of the as-grown nanostructures was fixed as single-crystalline.
Abstract: Nearly monodisperse Pd nanocubes with controllable sizes were synthesized through a seed-mediated growth approach. By using Pd nanocubes of 22 nm in size as seeds, the morphology of the as-grown nanostructures was fixed as single-crystalline, which enabled us to rationally tune the size of Pd nanocubes. The formation mechanism of initial 22 nm nanocubes was also discussed. The size-dependent surface plasmon resonance properties of the as-synthesized Pd nanocubes were investigated. Compared with previous methods, the yield, monodispersity, perfection of the shape formation, and the range of size control of these nanocubes are all improved. These Pd nanocubes may have potential interests in surface-enhanced Raman scattering, sensors, catalysis, study of size-dependent properties, and fabrication of high-order structures.
231 citations
TL;DR: In this paper, a simple and facile sonochemical route has been demonstrated for the shape-selective preparation of highly crystalline ZnO nanostructures, such as nanorods, nanocups, nanodisks, nanoflowers, and nanospheres.
Abstract: A simple and facile sonochemical route has been demonstrated for the shape-selective preparation of highly crystalline ZnO nanostructures, such as nanorods, nanocups, nanodisks, nanoflowers, and nanospheres. The concentration of precursor chemicals, the kind of hydroxide anion-generating agents, the ultrasonication time, and the use of a capping agent are key factors in the morphological control of ZnO nanostructures. This method is fast, simple, convenient, economical, and environmentally benign. On the basis of our shape-control of the ZnO nanostructures by the sonochemical technique, growth mechanisms of ZnO nanostructures were also proposed. We believe this technique will be readily adopted in realizing other forms of various nanostructured materials.
229 citations
TL;DR: In this paper, the self-assembly of MII ions, H3BTC or H2NDC with three structure-related flexible bis(imidazole) ligands, L1, L2, and L3, generated six metal-organic polymers.
Abstract: Via hydrothermal synthesis, the self-assembly of M(II) ions, H3BTC or H2NDC with three structure-related flexible bis(imidazole) ligands, L1, L2, and L3, generated six metal−organic polymers (M = Co, Ni, Zn; BTC = 1,3,5-benzenetricarboxylate, NDC = 1,2-benzenebicarboxylate, L1 = 1,4-bis(imidazol-1-ylmethyl)benzene, L2 = 1,1′-(1,4-butanediyl)bis(imidazole), L3 = 1,1′-(1,4-hexanediyl)bis (imidazole)): {Co3(L1)3(BTC)2(μ-H2O)3·2H2O}n (1), {Zn2(L2)(HBTC)2·2H2O}n (2), {Co(L3)(HBTC)}n (3), {Co(L1) (NDC)}n (4), {Ni(L2)(NDC)}n (5), and {Co(L3) (NDC)}n (6). The structure of 1 is the rare 4-connected self-penetrating metal−organic framework (MOF) with the (63)2(64·82)2(62·84) topology notation; polymers 2 and 6 are two-dimensional (2D) (3,4)-connected and 4-connected nets, respectively. If the O−H…O/2.631 A hydrogen bonds between HBTC2− dianions are not accounted for, then polymer 3 is a 2D (3,5)-connected net; contrarily, it is a pillar-layered three-dimensional supramolecular framework characterized by (4,5)-conne...
TL;DR: In this paper, the authors describe the comprehensive results of their investigation of interpenetration in organic hydrogen-bonded 3D arrays from the Cambridge Structural Database (CSDB).
Abstract: Interpenetration in extended three-dimensional (3D) arrays has been investigated by a systematic analysis of the crystallographic structural databases, using an ad hoc version of the program package TOPOS. In this paper we describe the comprehensive results of our investigation of interpenetration in organic hydrogen-bonded 3D arrays from the Cambridge Structural Database. The great interest in the self-assembly of organic molecules into hydrogen-bonded supramolecular arrays has prompted us to investigate these systems at a rather unusual level; that is, beyond the formation of synthons, we have examined the topologies of the resulting networks and looked for their entanglements. Within 3D architectures we have extracted a complete list including 122 different motifs showing the phenomenon of interpenetration (76 unseen by the original authors). These organic networks include species assembled by a single or by different building blocks; they are discussed and classified according to the previously introd...
TL;DR: In this article, the same two hydrogen bonds between the compound and the co-crystal former were found to be present in all the cocrystals for which they obtained single crystal structure.
Abstract: The pharmaceutical co-crystal approach has been introduced recently to address poor physicochemical properties of new chemical entities. In this study we prepared and investigated ten co-crystals of AMG 517. Based on thermal analysis, 1H NMR and pKa values we have prepared co-crystals rather than solvates or salts. We explored co-crystal physicochemical properties such as particle size, solubility, stability, hygroscopicity, and thermal properties as well as hydrogen bonding networks. We found that all co-crystals, for which we obtained single crystal structure, had the same two hydrogen bonds between the compound and the co-crystal former. In addition, we found good correlation between the melting point of the co-crystal former and the co-crystal but less correlation between the melting point and solubility of the co-crystals. In conclusion, within this series of co-crystals some design is possible by considering features of the compound and the co-crystal former.
TL;DR: It is demonstrated that the interactions between collagen and poly-l-aspartic acid are essential for the mineralized collagen fibrils formation, while collagen alone does not affect mineral formation andpoly- l-as Partic acid inhibits mineralization in a concentration dependant manner.
Abstract: Mineralized collagen fibrils constitute a basic structural unit of collagenous mineralized tissues such as dentin and bone. Understanding of the mechanisms of collagen mineralization is vital for development of new materials for the hard tissue repair. We carried out bio-inspired mineralization of reconstituted collagen fibrils using poly-l-aspartic acid, as an analog of non-collagenous acidic proteins. Transmission electron microscopy and electron diffraction studies of the reaction products revealed stacks of ribbon-shaped apatitic crystals, deposited within the fibrils with their c-axes co-aligned with the fibril axes. Such structural organization closely resembles mineralized collagen of bone and dentin. Initial mineral deposits formed in the fibrils lacked a long range crystallographic order and transformed into crystals with time. Interestingly, the shape and organization of these amorphous deposits was similar to the crystals found in the mature mineralized fibrils. We demonstrate that the interactions between collagen and poly-l-aspartic acid are essential for the mineralized collagen fibrils formation, while collagen alone does not affect mineral formation and poly-l-aspartic acid inhibits mineralization in a concentration dependant manner. These results provide new insights into basic mechanisms of collagen mineralization and can lead to the development of novel bio-inspired nanostructured materials.
TL;DR: Using a homogeneous precipitation method in an ultrasound field, this paper synthesized nanosized, plate-like hydroxyapatite (HAp), which consists of specifically oriented and laterally connected nanorods.
Abstract: Using a homogeneous precipitation method in an ultrasound field, we synthesized nanosized, platelike hydroxyapatite (HAp). The internal structure of these platelike formations consists of specifically oriented and laterally connected nanorods. The synthesized HAp nanorods have a length of about 500 nm and a diameter of about 100 nm. A closer inspection of the microstructure of a single nanorod revealed a highly regular and defect-free lattice with unique crystallographic plane orientations. The obtained structure was related to the influence of the ultrasound on the growth mechanism. The samples were characterized by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM).
TL;DR: Anion−π interactions are increasingly reported in the recent literature as mentioned in this paper, although many of these examples are described to be unique, a careful look in the Cambridge Structure Database reveals that many of the interactions are not uncommon but in fact have been overlooked in the past.
Abstract: Anion−π interactions are increasingly reported in the recent literature. Although many of these examples are described to be unique, a careful look in the Cambridge Structure Database reveals that many of these interactions are not uncommon but in fact have been overlooked in the past.
TL;DR: In this paper, three Keggin anion-based coordination polymers with different dimensionalities were synthesized and structurally characterized by tuning the spacer length of flexible bis(triazole) ligands.
Abstract: Through tuning the spacer length of flexible bis(triazole) ligands, three Keggin anion-based coordination polymers with different dimensionalities, [Cu4(H2O)4(bte)2(HPMoVI10MoV2O40)]·2H2O (1) (bte = 1,2-bis(1,2,4-triazol-1-yl)ethane), [Cu(btb)][Cu2(btb)2(PMo12O40)] (2) (btb = 1,4-bis(1,2,4-triazol-1-y1)butane), and [Cu5(btx)4(PMoVI10MoV2O40)] (3) (btx = 1,6-bis(1,2,4-triazol-1-y1)hexane), were synthesized and structurally characterized. Compound 1 exhibits a ladder-like chain, in which the polyoxometalate (POM) anions act as the “middle rails” of the ladder. The bte ligand with shortest spacer length acts as not only the bridging linker but also the chelator, which terminates the dimensional extension. Compound 2 exhibits a 2D POM-based framework, containing POM/Cu/btb grid-like layers. In compound 3, there exist three sets of (123)(121)2 2D Cu-btx frameworks to generate a 3-fold interpenetrating structure, into which the hexadentate POM anions are inserted to construct a 3D structure. The structural anal...
TL;DR: The reaction of pyridine-2,6-dicarboxylic acid (H2PDA) and oxalic acid with Ln2O3/Ce(NO3)3 under hydrothermal conditions generated a series of new one-, two-, and three-dimensional (1D, 2D,...
Abstract: The reaction of pyridine-2,6-dicarboxylic acid (H2PDA) and oxalic acid (H2ox) with Ln2O3/Ce(NO3)3 under hydrothermal conditions generated a series of new one-, two-, and three-dimensional (1D, 2D, ...
TL;DR: In this article, the coordination polymers were determined by single-crystal X-ray diffraction analyses and further characterized by elemental analyses, IR spectra, and thermogravimetric analyses.
Abstract: Seven coordination polymers, namely [Zn(BPTC)0.5(L1)0.5(H2O)] (1), [Zn2(BPTC)(L2)]·H2O (2), [Zn2(BPTC)(L3)2]·3H2O (3), [Zn2.5(BPTC)(L4)(OH)(H2O)] (4), [Zn2(BPTC)(L5)(H2O)2]·3H2O (5), [Cd2(BPTC)(L5)(H2O)]·H2O (6), and [Cd(BPTC)0.5(L6)]·H2O (7), where L1 = 4,4′-bis(imidazol-1-ylmethyl)bibenzene, L2 = 4,4′-bis(imidazol-1-ylmethyl)benzene, L3 = 1,4-bis(imidazol-1-yl)butane, L4 = 1,4-bis(2-ethyl-imidazol-1-yl)butane, L5 = 1,3-bis[2-(2-pyridyl)imidazol-1-ylmethyl]benzene, L6 = 1,2-bis[2-(2-pyridyl)imidazol-1-ylmethyl]benzene, and BPTC = 3,3′,4,4′-benzophenone tetracarboxylate ligand, have been synthesized under hydrothermal conditions. Their structures have been determined by single-crystal X-ray diffraction analyses and further characterized by elemental analyses, IR spectra, and thermogravimetric analyses. The structure of 1 exhibits a (4,6)-connected network with a (44·62)(44·610·8) topology formed by L1 ligands connecting BPTC−Zn sheets. The structure of 2 is a chiral 3D network in which there exists a Zn−O...
TL;DR: In this paper, a facile route using a hydrothermal treatment and sequential thermal decomposition without employing any template or surfactant was used to synthesize nanoporous hollow microspheres and nanocubes.
Abstract: In this work, we report on the preparation of nanoporous γ-MnO2 with different morphologies and their application in rechargeable Li-ion batteries. Nanoporous γ-MnO2 has been successfully synthesized via a facile route using a hydrothermal treatment and sequential thermal decomposition without employing any template or surfactant. Through simply altering the reactant, nanoporous hollow microspheres and nanocubes can be selectively prepared. The influence caused by different reaction conditions on the structure and morphology of the products has been discussed in detail. It is found that the reactant NH4HCO3 and hydrothermal treatment are necessary for preparing the hollow microspheres. The thermal decomposition of the precursor leads to formation of the nanoporous structure. Both the as-prepared γ-MnO2 hollow microspheres and the nanocubes exhibit promising electrochemical properties as the anode materials of rechargeable Li-ion batteries. In particular, the initial reversible capacity for the hollow micr...
TL;DR: The effect of dopants (over a concentration range from 1 to 10 mol %) on the growth process, crystalline perfection, and nonlinear optical properties of ammonium dihydrogen phosphate (NH4H2PO4, ADP) single crystals grown by a slow evaporation solution growth technique has been investigated in this paper.
Abstract: The effect of dopants (over a concentration range from 1 to 10 mol %), namely KCl and oxalic acid (C2H2O4·2H2O, Oxa), on the growth process, crystalline perfection, and nonlinear optical (NLO) properties of ammonium dihydrogen phosphate (NH4H2PO4, ADP) single crystals grown by a slow evaporation solution growth technique has been investigated. The high-resolution X-ray diffraction (HRXRD) studies used to evaluate crystalline perfection reveal some interesting features on the ability of accommodating the dopants by the crystalline matrix. The remarkable and systematic increase in the broadness and asymmetry of the diffraction curves as the concentration increases clearly indicates that the dopants predominantly occupied the interstitial positions in the crystalline matrix. Due to the larger size of the Oxa molecule, the crystalline matrix could not accommodate these dopants, which led to the formation of a very low angle (tilt angle <1′) internal structural grain boundaries at high concentrations. The rela...
TL;DR: In this paper, two-dimensional (2D) single-crystalline bismuth oxyhalides (BiOX, X = Cl, Br) micro-and nanostructures, such as nanoplates, nanosheets, and microsheets, were synthesized in a large scale by a simple wet chemistry approach of hydrogen peroxide (H2O2) direct oxidation of bulk metal Bismuth (Bi) particles in a mixed solution followed by a hydrothermal treatment.
Abstract: In this article, for the first time, two-dimensional (2D) single-crystalline bismuth oxyhalides (BiOX, X = Cl, Br) micro- and nanostructures, such as nanoplates, nanosheets, and microsheets, were synthesized in a large scale by a simple wet chemistry approach of hydrogen peroxide (H2O2) direct oxidation of bulk metal bismuth (Bi) particles in a mixed solution followed by a hydrothermal treatment, instead of previous coprecipitation of Bi salts route. The in-plane size and thickness of the 2D products can be conveniently tailored by varying the temperature and the concentrations of the Bi precursor. The products were characterized by a range of methods, such as X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, high-resolution transmission microscopy, energy-dispersive X-ray spectroscopy, selected area electron diffraction, thermogravimetric analysis, Fourier transform infrared spectra, and UV−vis diffuse reflectance spectra. The BiOBr nanoplates, nanosheets, and micr...
TL;DR: In this article, five new metal−organic frameworks were synthesized under hydrothermal conditions by employing mixed ligands of various carboxylic acids with bix (or mbix).
Abstract: Five new metal−organic frameworks, namely, [Cd(HIDC)(bix)]n (1), [Cd2(BDC)2(mbix)H2O]n (2), [Cd(HBTEC)(H2bix)0.5]n (3), [Cd(BTEC)(H2mbix)]n (4), and [Zn(BTEC)0.5(mbix)]n (5) (H3IDC = imidazole 4,5-dicarboxylic acid, H2BDC = 1,4-benzenedicarboxylate, H4BTEC = 1,2,4,5-benzenetetracarboxylate, bix = 1,4-bis(imidazol-1-ylmethyl)-benzene, and mbix = 1,3-bis(imidazol-1-ylmethyl)-benzene), have been synthesized under hydrothermal conditions by employing mixed ligands of various carboxylic acids with bix (or mbix). Coordination polymer 1 is a 3-fold-interpenetrated diamondoid network. Particularly, in 1 there occur triple-stranded helices based on Cd ions and bix ligands when viewed along b axis. Coordination polymer 2 is a 2D infinite layer framework, which is further interconnected by hydrogen-bond interactions leading to a 3D supramolecular architecture. Both 3 and 4 feature a 3D open framework with protonated bix (or mbix) locating in the channels, and the 3D open frameworks can be rationalized as a zeolite A...
TL;DR: In this article, a chiral 2D sheet of [M(HIDC)(H2O)(prz)0.5]n was synthesized and characterized by single-crystal X-ray diffraction, in which the helical chains are packed in an alternating left and right-handed chirality.
Abstract: Four achiral two-dimensional (2D) coordination polymers of [M(HIDC)(H2O)(prz)0.5]n (M = Fe, 1; Mn, 2; Cd, 3) and [Co(HIDC)(H2O)(pyz)0.5]n (4), one chiral 2D coordination polymer of [Mn(HIDC)(H2O)]n (5), and one 2D coordination polymer of [Fe(HIDC)(H2O)]n (6) (H3IDC = imidazole-4,5-dicarboxylic acid, prz = piperazine, pyz = pyrazine) were hydrothermally synthesized and characterized by single-crystal X-ray diffraction. In 1–3, the HIDC2− anions alternately bridge the M(II) cations to form a one-dimensional (1D) infinite helical chain of [M(HIDC)]∞ along the 21 axis. The chirality of the original formed helical chain is transferred oppositely to neighboring helical chains through the parallel coordination interactions of prz molecules between two adjacent chains, resulting in an achiral 2D sheet of [M(HIDC)(H2O)(prz)0.5]n, in which the helical chains are packed in an alternating left- and right-handed chirality. A similar achiral 2D coordination polymer of 4 was obtained when pyz was used as a linker. Compo...
TL;DR: In this paper, three 3D multifunctional microporous metal−organic frameworks (MOFs) were synthesized by self-assembly of a rigid tetra-carboxylate ligand H4ABTC and corresponding transition metal salts under mild conditions.
Abstract: Three 3D multifunctional microporous metal−organic frameworks (MOFs), Cu2(ABTC)(H2O)2·(DMF)2(H2O) (JUC-62), Cd2(ABTC)(DMF)3·(DMF)2 (JUC-63), and Mn(H2ABTC)(DMF)2 (JUC-64) (H4ABTC = 3,3′,5,5′-azobenzenetetracarboxylic acid, DMF = N,N′-dimethylformamide, and JUC = Jilin University China) have been synthesized by self-assembly of a rigid tetra-carboxylate ligand H4ABTC and corresponding transition metal salts under mild conditions. X-ray crystallography reveals that their topologies are based on NbO (JUC-62) and PtS (JUC-63 and JUC-64) nets, constructed of 4-connected rectangular ABTC4− units with 4-connected square paddle-wheel Cu2(CO2)4(H2O)2 secondary building units (SBUs), tetrahedral bimetallic Cd2(CO2)4(DMF)3 SBUs, and tetrahedral monometallic Mn(CO2)4(DMF)3 SBUs, respectively. High-pressure hydrogen sorption of the activated JUC-62 reveals a type I profile at 77 K, which is saturated at 40 bar with a hydrogen uptake of about 4.71 wt%. Photoluminescence investigations reveal that JUC-62 and JUC-63 disp...
TL;DR: In this paper, a facile and bioinspired synthesis of ZnO hierarchical architectures, including prismlike and flowerlike structures and crytalline and noncrystalline hollow microspheres, has been developed using the amino acid histidine as the directing and assembling agent.
Abstract: A facile and bioinspired synthesis of ZnO hierarchical architectures, including prismlike and flowerlike structures and crytalline and noncrystalline hollow microspheres, has been developed using the amino acid histidine as the directing and assembling agent. The histidine molecules play different roles in the formation of ZnO hierarchical architectures due to the competitive coordination between histidine and OH− to Zn2+ when the reactant molar ratios are adjusted. The resulting architectures are characterized using field-emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and high-resolution TEM (HRTEM), X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectoscopy, and thermogravimetric analysis (TGA). Morphology- and phase-dependent photoluminescence of the ZnO architectures has been shown. In particularly, a novel photocatalytic activity of the ZnO hierarchical architectures for the reaction of the formaldehyde and carbon dioxide has been demonstrated, prob...
TL;DR: In this paper, a new rare-earth polymeric framework RPF-4 has been obtained and its structure solved from an intrinsically triple twinned crystal, which makes them very promising materials for light-emitting diodes.
Abstract: A new family of rare-earth polymeric framework RPF-4 has been obtained and its structure solved from an intrinsically triple twinned crystal. The framework formed by a H−O bond free rare-earth matrix, with the Ln atoms separated in two directions, makes them very promising materials for light-emitting diodes. The properties of the materials as heterogeneous catalysts are reported, too. IR spectroscopy suggests the presence of a peroxo complex that acts as active species in the oxidation reaction.
TL;DR: In this article, a controllable synthesis of MgO with various morphologies by adjusting the composition and phase structure of magnesium carbonate hydrate (MCH) was developed.
Abstract: We have developed a method of controllable synthesis of MgO with various morphologies by adjusting the composition and phase structure of magnesium carbonate hydrate (MCH) The phase structure of the MCH varied from monoclinic Mg5(CO3)4(OH)2(H2O)4 to hexagonal MgCO3 by changing the concentration of Mg2+ and HCO3−; the corresponding morphology of the MCH ranges from nanoflakes and flowerlike microspheres composed of nanoflakes to layer-like rhombohedra and microspheres composed of rhombohedra After annealing, four kinds of mesoporous cubic MgO micronano structures were obtained with their original morphologies Because of the high specific surface area, MgO mesoporous nanoflakes and flowerlike microsphers exhibited excellent absorption performance for common toxic heavy metal ions and organic pollutants and are expected to be a potential absorbent in wastewater treatment
TL;DR: A slurry crystallization technique was used in cocrystal screening of two nonionizable pharmaceutical host compounds, stanolone and mestanolone, with 11 pharmaceutically acceptable guest acids as mentioned in this paper.
Abstract: A slurry crystallization technique was used in cocrystal screening of two nonionizable pharmaceutical host compounds, stanolone and mestanolone, with 11 pharmaceutically acceptable guest acids. Crystallization was performed simply by adding crystallization solvents to solid mixtures of a host and a guest, which had been prepared using lyophilization of their dimethyl sulfoxide solution. Powder X-ray diffraction and thermogravimetric/differential thermal analysis were used to identify new solid forms. Two resultant new forms, stanolone l-tartaric acid 1:1 cocrystal and mestanolone salicylic acid 1:1 cocrystal, were characterized using single-crystal X-ray diffraction. The hosts, despite having the same steroidal skeleton and the same functional groups that form strong hydrogen bonds, each formed a cocrystal with a different guest molecule. All functional groups of the host and guest molecules that form strong hydrogen bonds were engaged in hydrogen bonding, but, despite the highly analogous molecular struc...
TL;DR: Molecular similarity and supramolecular dissimilarity are discussed with reference to the definition of the term polymorph.
Abstract: Molecular similarity and supramolecular dissimilarity are discussed with reference to the definition of the term polymorph.