Showing papers in "Crystal Growth & Design in 2014"

Applied Topological Analysis of Crystal Structures with the Program Package ToposPro

Abstract: Basic concepts of computer topological analysis of crystal structures realized in the current version of the program package ToposPro are considered. Applications of the ToposPro methods to various classes of chemical compounds—coordination polymers, molecular crystals, supramolecular ensembles, inorganic ionic compounds, intermetallics, fast-ion conductors, microporous materials—are illustrated by many examples. It is shown that chemically and crystallographically different structures can be automatically treated in a similar way with the ToposPro approaches.

Detailed Structure Analysis of Atomic Positions and Defects in Zirconium Metal‒Organic Frameworks

Abstract: We report the structure of the Zr metal–organic frameworks (MOFs) UiO-66 and UiO-67 to very fine detail using synchrotron single-crystal X-ray diffraction and the synthesis method used to obtain single crystals. Zr terephthalate MOF UiO-66 is known to have missing linkers, and the nature of these are shown to be coordinating water and solvent molecules. Single crystals of the isoreticular material UiO-67 does not show such missing linker defects.

Crystal Packing of Low-Sensitivity and High-Energy Explosives

Abstract: Low-sensitivity and high-energy explosives (LSHEs) are highly desired for their comprehensive superiority of safety and energy. Crystal packing is crucial to both the safety and energy, and therefore becomes of interest in energetic crystal engineering. This work carries out systemic analyses on the crystal packing of 11 existing LSHEs with both energy and safety close or superior to TNT. As a result, we find that the LSHE crystals wholly feature π–π stacking with the aid of intermolecular hydrogen bonding. Each LSHE molecule is π-bonded with a big conjugated structure composed of all non-hydrogen atoms in the entire molecule. Intramolecular hydrogen bonding exists in most LSHE molecules with strongly active hydrogen bond (HB) donors of amino and hydroxyl groups, and various strength. These big π-conjugated structures and intramolecular HBs lead to planar molecules with high stability, settling a base of π–π stacking in crystals. With the help of intermolecular HBs, the π–π stacking holding the LSHE cryst...

Defect Engineering in Ce-Doped Aluminum Garnet Single Crystal Scintillators

Abstract: Mg-codoped Lu3Al5O12:Ce single crystal scintillators were prepared by a micropulling down method in a wide concentration range from 0 to 3000 ppm of Mg codopant. Their structure and chemical composition were checked by X-ray diffraction and electron probe microanalysis techniques. Absorption and luminescence spectra, photoluminescence decays, and thermoluminescence glow curves were measured together with several other scintillation characteristics, namely, the scintillation decay, light yield, afterglow, and radiation damage to reveal the effect of Mg codoping. Several material characteristics manifest a beneficial effect of Mg codopant. We propose a model explaining the mechanism of material improvement which is based on the stabilization of a part of the cerium dopant in the tetravalent charge state. The stable Ce4+ center provides an additional fast radiative recombination pathway in the scintillation mechanism and efficiently competes with electron traps in garnet scintillators.

Naming Interactions from the Electrophilic Site

Abstract: It is proposed that noncovalent interactions, wherein it is possible to identify an element or moiety working as the electrophile, are named by referring to the Group of the Periodic Table the electrophilic atom belongs to. The resulting terminology generalizes a criterion which was used in the recent IUPAC definition of halogen bond and inspired the definition of hydrogen bond. A systematic, unambiguous, and periodic naming is obtained and applies to the majority of the attractive interactions formed by the elements of Groups 1, 2, 13–17 and, possibly, to some interactions formed by the elements of other Groups.

Facile Fabrication of WO3 Nanoplates Thin Films with Dominant Crystal Facet of (002) for Water Splitting

Abstract: Single crystalline orthorhombic phase tungsten trioxide monohydrate (O-WO3·H2O, space group: Pmnb) nanoplates with a clear morphology and uniform size distribution have been synthesized by the hydrothermal method and fabricated on the surface of fluorine doped tin oxide (FTO) coated glass substrates with selective exposure of the crystal facet by the finger rubbing method. The rubbing method can easily arrange the O-WO3·H2O nanoplates along the (020) facet on the FTO substrate. The O-WO3·H2O nanoplate can be converted to monoclinic phase WO3 (γ-WO3, space group: P21/n) with dominant crystal facet of (002) without destroying the plate structure. Crystal morphologies, structures, and components of the powders and films have been determined by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Raman, X-ray photoelectron spectroscopy, etc. The band gap energies of the O-WO3·H2O and γ-WO3 nanoplates were determined as ca. 2.26 and 2.49 eV, respectively. Photoelectrochemical prop...

Polynuclear CdII Polymers: Crystal Structures, Topologies, and the Photodegradation for Organic Dye Contaminants

Abstract: To systematically explore the effect of polynuclear complexes on photocatalytic degradation of the organic dyes, a series of coordination complexes containing CdII clusters, formulated as {[Cd3L2(H2O)5]·H2O}n (1), {[Cd3L2(hbmb)(H2O)2]·2.5H2O}n (2), {[Cd3L2(btbb)(H2O)2]·2EtOH·1.5H2O}n (3), and {[Cd6L4(bipy)2(H2O)6]·3H2O}n (4) (H3L = 3,4-bi(4-carboxyphenyl)-benzoic acid, hbmb = 1,1′-(1,6-hexane)bis(2-methylbenzimidazole), btbb = 1,4-bis(2-(4-thiazolyl)benzimidazole-1-ylmethyl)benzene, 4,4′-bipy = 4,4′-bipyridine), have been designed and synthesized. Complex 1 based on trinuclear CdII clusters exhibits a new (3,3,6)-connected 3D framework. 2 belongs to a (3,3,8,8)-connected tfz-d topology net with pillar-layered frameworks assembled by two kinds of trinuclear CdII clusters. 3 is a 3D pillar-layered framework, which features a (3,8)-connected tfz-d net based upon one kind of trinuclear CdII cluster. 4 presents a new 3D (3,6,10)-connected framework with dinuclear and tetranuclear clusters. The photocatalytic p...

Crystal Packing of Impact-Sensitive High-Energy Explosives

Abstract: Molecular and crystal designs are crucial to the engineering of high-energy explosives, which are a class of substantial materials usually with high costs and high risks. Understanding their structures, properties, and performances, and the relationships among them is the basis for the design. As a continuation of a systemic analysis of the crystal packing of low-sensitivity and high-energy explosives (LSHEs) (Cryst. Growth Des. 2014, 14, 4703−4713), we present in this work another analysis of 10 existing impact-sensitive high-energy explosives (SHEs), which possess both velocities of detonation and impact sensitivity close to or higher than those of RDX. We find that SHE molecules are usually less stable than LSHE ones, due to the deficiencies of big π-conjugated molecular structures, and adequate and strong intramolecular hydrogen bonds (HBs) even though H atoms are contained. The intermolecular HBs cannot be formed sometimes in H-contained SHE crystals, and the noncovalent O···O interactions dominate t...

Nanoscaled M-MOF-74 Materials Prepared at Room Temperature

Abstract: This paper describes the preparation and characterization of nanoscaled M-MOF-74/CPO-27-M (M = Mg, Mn, Co, Ni, and Zn) materials at room temperature. Some of the so-formed crystals are the smallest ones of any metal–organic framework (MOF) material (and, to the best of our knowledge, of any microporous material) ever reported. They are at the limit of being able to diffract, particularly those forming the Co- and Ni-MOF-74 samples. Consequently, unequivocal identification as the crystalline MOF-74 phase was deduced by combining other characterization techniques rather than powder X-ray diffraction. These small crystals are unstable as isolated ones, so they form steady and robust aggregates, whose mechanical properties strongly depend on the crystal size. The particles that result from the “fusion” of nanocrystals smaller than 10 nm (more properly denoted as nanodomains) could not be disaggregated by conventional ultrasonic and graining techniques. On the contrary, agglomerates of crystals larger than 10 ...

Crystal transformation in zeolitic-imidazolate framework

Abstract: The phase transformation of a zinc-2-methylimidazole-based zeolitic-imidazolate framework (ZIF), from a recently discovered ZIF-L to ZIF-8, was reported. ZIF-L is made up of the same building blocks as ZIF-8, having two-dimensional crystal lattices stacked layer-by-layer. Results indicated that the phase transformation occurs in the solid phase via the geometric contraction model (R2), a kinetic model new to ZIF. The phase transformation was monitored by means of ex situ powder X-ray diffraction, nitrogen sorption, Fourier transform infrared spectroscopy, selected-area electron diffraction, scanning electron microscopy, and in situ nuclear magnetic resonance spectroscopy. This work also demonstrates the first topotactic phase transformation in porous ZIFs, from a 2D layered structure to a 3D structure, and provides a new insight into metal–organic framework crystallization mechanisms.

Selective CO2 Capture in Metal–Organic Frameworks with Azine-Functionalized Pores Generated by Mechanosynthesis

Abstract: Two new three-dimensional porous Zn(II)-based metal–organic frameworks, containing azine-functionalized pores, have been readily and quickly isolated via mechanosynthesis, by using a nonlinear dicarboxylate and linear N-donor ligands. The use of nonfunctionalized and methyl-functionalized N-donor ligands has led to the formation of frameworks with different topologies and metal–ligand connectivities and therefore different pore sizes and accessible volumes. Despite this, both metal–organic frameworks (MOFs) possess comparable BET surface areas and CO2 uptakes at 273 and 298 K at 1 bar. The network with narrow and interconnected pores in three dimensions shows greater affinity for CO2 compared to the network with one-dimensional and relatively large pores—attributable to the more effective interactions with the azine groups.

Toward a Detailed Understanding of Magnesium Ions on Hydroxyapatite Crystallization Inhibition

Abstract: Magnesium ions (Mg2+) are widely present in biological fluids, and they are suggested as the vital factors that inhibit spontaneous hydroxyapatite (HAP) precipitation in nature. However, the regulation mechanisms of Mg2+ on HAP crystallization are still under intensive debates. We find that a typical precipitation of HAP from supersaturated solutions should include five stages: s1, formation of ion clusters and amorphous calcium phosphate (ACP); s2, stabilization of ACP; s3, transformation from ACP to HAP via dissolution and crystallization; s4, classical crystal growth of HAP; s5, HAP aging under a near equilibrium state. Actually, Mg2+ ions exhibit different inhibitory effects on these stages. The ions have a negligible influence on the kinetics of initial ACP formation in solutions (s1) and final aging of crystals (s5). Rather, the ions can either adsorb onto or incorporate into the ACP precursor particles during s1. In s2, the lifetime of ACP in solution is extended significantly by both two types of ...

Three Zinc(II) Coordination Polymers Based on Tetrakis(4-pyridyl)cyclobutane and Naphthalenedicarboxylate Linkers: Solvothermal Syntheses, Structures, and Photocatalytic Properties

Abstract: Solvothermal reactions of Zn(NO3)2 with tetrakis(4-pyridyl)cyclobutane (tpcb) and 1,4-naphthalenedicarboxylic acid (1,4-H2ndc) and 2,3-naphthalenedicarboxylic acid (2,3-H2ndc) in different solvents led to the formation of three polydimensional coordination polymers {[Zn2(H2O)(1,4-ndc)2(tpcb)]}n (1), {[Zn(1,4-ndc)(tpcb)0.5]}n (2), and {[Zn2(H2O)(2,3-ndc)2(tpcb)]}n (3). Compounds 1–3 were characterized by elemental analysis, IR, powder X-ray diffraction (PXRD), and single crystal X-ray diffraction. Compound 1 is a three-dimensional (3D) (3,3)-connected net with a (10·122)·(102·12) Schlafli symbol. Compound 2 holds a 2-fold interpenetrating 3D framework with a (42·62·72)·(4·62·73) Schlafli symbol, which shows hexagonal-prism-like one-dimensional channels. Compound 3 shows a two-dimensional (3,8)-connected network. The solid state luminescent, optical, and thermal stability properties of 1–3 at ambient temperature were also investigated. A comparative study on their photocatalytic activity toward the degradat...

Luminescent Anionic Metal–Organic Framework with Potential Nitrobenzene Sensing

Abstract: Solvothermal reaction of multidentate organic ligand, 5,5′,5″,5‴,5],5]′-[1,2,3,4,5,6-phenylhexamethoxyl]hexaisophthalic acid (H12L), with Cd(NO3)·4H2O produced an anionic 3D metal–organic framework [(CH3)2NH2]4[Cd3(H2L)] (1), which features a novel cage-to-cage connection. Interestingly, the 1D channel, which is stacked by cages, is divided into uniform segments by molecular-scale bricks. The luminescent properties of compound 1 have been explored, which shows that 1 is a potential luminescent sensory material for nitrobenzene.

Multifunctional Cobalt(II) Coordination Polymers Tuned by Flexible Bis(pyridylamide) Ligands with Different Spacers and Polycarboxylates

Abstract: Ten multifunctional cobalt(II) coordination polymers with the formulas of [Co(L1)0.5(5-AIP)]·H2O (1), [Co(L2)(5-AIP)(H2O)2] (2), [Co(L3)0.5(5-AIP)] (3), [Co(L4)0.5(5-AIP)(H2O)]·2H2O (4), [Co(L5)(5-AIP)] (5), [Co(HBTC)(L3)]·H2O (6), [Co(HBTC)(L6)(H2O)]·3H2O (7), [Co(L2)(1,3-BDC)(H2O)2] (8), [Co2(L3)2(1,3-BDC)2]·4H2O (9), and [Co2(L4)1.5(1,2-BDC)(μ2-OH)(μ3-OH)(H2O)]·H2O (10) have been prepared by a hydrothermal technique employing six flexible bis(pyridylamide) ligands with different spacers (L1 = N,N′-bis(3-pyridyl)oxamide, L2 = N,N′-bis(3-pyridyl)malonamide, L3 = N,N′-di(3-pyridyl)succinamide, L4 = N,N′-bis(3-pyridyl)adipamide, L5 = N,N′-bis(3-pyridyl)heptandiamide, L6 = N,N′-bis(3-pyridyl)sebacicdiamide) and four aromatic polycarboxylic acids mixed ligands (5-H2AIP = 5-aminoisophthalic acid, H3BTC = 1,3,5-benzenetricarboxylic acid, 1,3-H2BDC = 1,3-benzenedicarboxylic acid, and 1,2-H2BDC = 1,2-benzenedicarboxylic acid). Compound 1 exhibits a two-dimensional (2D) double-layer network. Compounds 2 and 8 are...

Experimental and Computational Study of Counterintuitive ClO4–···ClO4– Interactions and the Interplay between π+–π and Anion···π+ Interactions

Abstract: The novel noncovalent interactions between the charged and neutral aromatic rings and with anions are utilized to design the solid-state assembly of triply protonated PTPH3 (PTP = 4′-(4-pyridyl)-3,2′:6′,3″-terpyridine) with H2O and three ClO4–, which is synthesized and characterized by single-crystal X-ray diffraction analysis. Crystallography reveals that the π+–π+, π+–π, and various anion···π interactions are the major driving forces in the stabilization of the self-assembled structure. In the title complex, a layered assembly is formed through the mutual influence of π+–π+ and π+–π interactions. The anions are interacting with the charged π-acceptors, which are again stabilized through π+–π interactions. Therefore, the overall stabilization is governed through π+–π/π–π+, (π+–π+)n, and anion···π+/π+–π/π–π+ networks in the solid state. The interaction energies of the main driving forces observed in the crystal structure have been calculated using density functional theory. In addition, the short O···O co...

Comprehending the Formation of Eutectics and Cocrystals in Terms of Design and Their Structural Interrelationships

Abstract: The phenomenon of cocrystallization, which encompasses the art of making multicomponent organic solids such as cocrystals, solid solutions, eutectics, etc. for novel applications, has been less studied in terms of reliably and specifically obtaining a desired cocrystallization product and the issues that govern their formation. Further, the design, structural, and functional aspects of organic eutectics have been relatively unexplored as compared to solid solutions and cocrystals well-established by crystal engineering principles. Recently, eutectics were proposed to be designable materials on par with cocrystals, and herein we have devised a systematic approach, based on the same crystal engineering principles, to specifically and desirably make both eutectics and cocrystals for a given system. The propensity for strong homomolecular synthons over weak heteromolecular synthons and vice versa during supramolecular growth was successfully utilized to selectively obtain eutectics and cocrystals, respectively, in two model systems and in two drug systems. A molecular level understanding of the formation of eutectics and cocrystals and their structural interrelationships which is significant from both fundamental and application viewpoints is discussed. On the other hand, the obscurity in establishing a low melting combination as a eutectic or a cocrystal is resolved through phase diagrams.

Revealing the roles of desolvation and molecular self-assembly in crystal nucleation from solution : benzoic and p -aminobenzoic acids

Abstract: There has been much recent interest in the role of solution chemistry and in particular the importance of molecular self-assembly in the nucleation of crystalline phases. Techniques such as FTIR and NMR have highlighted the existence of solution-phase dimers which in many cases mirror the structural synthons found in the resulting macroscopic crystals. However, there are no reported examples in which this new insight into the solution phase has been linked directly to the kinetics of crystal nucleation. Here for the first time, using a combination of solution FTIR, computational chemistry, and measured crystal nucleation rate data, such a link is demonstrated for p-aminobenzoic (PABA) and benzoic acids nucleating from polar and nonpolar solvents. Solute dimerization and desolvation are found to be rate-determining processes in the overall nucleation pathway.

Two Series of Solvent-Dependent Lanthanide Coordination Polymers Demonstrating Tunable Luminescence and Catalysis Properties

Abstract: Two series of lanthanide–organic frameworks with the formulas [Ln(BTATB)(DMF)2(H2O)]·DMF·2H2O (Ln = La (1a), Eu (2a), Tb (3a), Er (4a)) and [Ln(BTATB)(H2O)2]·2DMA·4H2O (Ln = Er (1b), Yb (2b), Lu (3b)), respectively, were solvothermally synthesized from 4,4′,4″-(benzene-1,3,5-triyltris(azanediyl))tribenzoate (H3BTATB) and Ln(NO3)3 under DMF or DMA media and characterized by thermogravimetric analyses, IR spectroscopy, X-ray powder diffraction, and single crystal X-ray diffraction. X-ray single-crystal diffraction analyses for these complexes revealed that series A features an interesting 2D interdigitated layer architecture with (6,3) topology. Series B exhibits a 2D bilayer structure. The luminescence properties were studied, and the results showed that complex 3a displayed strong fluorescent emission in the visible region, where the emission intensities of 3a are enhanced upon the addition of Zn2+, demonstrating Zn2+-modulated fluorescence. Yb(III) complex 2b emits typical near-infrared luminescence (983...

Continuous-Flow Tubular Crystallization in Slugs Spontaneously Induced by Hydrodynamics

Abstract: A novel continuous crystallizer design is described with the potential to provide improved control of crystal properties, improved process reproducibility, and reduced scale-up risk. Liquid and gas are introduced into one end of the tube at flow rates selected to spontaneously generate alternating slugs of liquid and gas that remain stable while cooling crystallization occurs in each liquid slug. Mixing within each stable self-circulating slug is maximized by controlling the slug aspect ratio through specification of liquid and gas flow rates. The crystallizer is designed so that nucleation and growth processes are decoupled to enhance the individual control of each phenomenon. Coaxial or radial mixers combine liquid streams to generate seed crystals immediately upstream of the growth zone where nucleation is minimized, and crystal growth is controlled by the varying temperature profile along the length of the tube. The slug-flow crystallizer design is experimentally demonstrated to generate large uniform...

Solvent/Temperature and Dipyridyl Ligands Induced Diverse Coordination Polymers Based on 3-(2′,5′-Dicarboxylphenyl)pyridine

Abstract: Eleven new multidimensional transition coordination polymers, [Cd2(dcpy)2(H2O)] (1), [Cd(dcpy)]·H2O (2), [Cd(dcpy)(H2O)1.5]·2H2O (3), [Cd(dcpy)(bipy)0.5(H2O)]·5H2O (4), [Cd2(dcpy)2(bipy)(H2O)3]·2.5H2O (5), [Cd2(dcpy)2(bipy)]·4H2O (6), [Cd(dcpy)(bpa)0.5]·2H2O (7), [Ni(dcpy)(H2O)2] (8), [Ni(dcpy)(bpe)0.5(H2O)]·3H2O (9), [Ni(dcpy)(bpe)0.5(H2O)]·0.5H2O (10), and [Ni(dcpy)(bpa)0.5(H2O)2]·H2O (11), have been synthesized by using a tritopic ligand 3-(2′,5′-dicarboxylphenyl)pyridine acid (H2dcpy) and three different N-donor ancillary ligands (bipy = 4,4′-bipyridine, bpe = 1,2-bi(4-pyridyl)ethene, and bpa = 1,2-bi(4-pyridyl)ethane) in different solvents and temperatures. 1 is a four-connected three-dimensional (3D) framework based on two kinds of Cd–O–Cd and Cd–(COO)–Cd chains. 2 shows also a four-connected 3D framework with one-dimensional (1D) channels formed by double left- and right-handed helical chains. 3 displays a 3D microporous framework composed of Cd2O3 as a secondary building unit (SBU) with a (4,6)-co...

Obtaining Synthon Modularity in Ternary Cocrystals with Hydrogen Bonds and Halogen Bonds

Abstract: Design of ternary cocrystals based on synthon modularity is described. The strategy is based on the idea of extending synthon modularity in binary cocrystals of 4-hydroxybenzamide:dicarboxylic acids and 4-bromobenzamide:dicarboxylic acids. If a system contains an amide group along with other functional groups, one of which is a carboxylic acid group, the amide associates preferentially with the carboxylic acid group to form an acid–amide heterosynthon. If the amide and the acid groups are in different molecules, a higher multicomponent molecular crystal is obtained. This is a stable pattern that can be used to increase the number of components from two to three in a multicomponent system. Accordingly, noncovalent interactions are controlled in the design of ternary cocrystals in a more predictable manner. If a single component crystal with the amide–amide dimer is considered, modularity is retained even after formation of a binary cocrystal with acid–amide dimers. Similarly, when third component halogen a...

Cocrystals of the Tuberculosis Drug Isoniazid: Polymorphism, Isostructurality, and Stability

Abstract: Isoniazid (INH) is a key drug ingredient in the fixed dose combination for the treatment of tuberculosis (TB). INH is highly soluble in aqueous medium and also stable in pure form, but it undergoes degradation when it is part of the FDC due to cross reactions. In continuation of our studies to improve the physiochemical properties of INH, we performed a cocrystal screen with pharmaceutically acceptable molecules selected from the generally regarded as safe (GRAS). Cocrystals with acidic conformers, such as vanillic acid (VLA), ferulic acid (FRA), caffeic acid (CFA), as well as with hydroxyl coformer resorcinol (RES), are reported. INH–VLA and INH–FRA are dimorphic, and INH–CFA is trimorphic. Form-1 of INH–FRA and INH–VLA are two-dimensional isostructural. All cocrystal structures are sustained by the expected acid–pyridine synthon, except the isostructural cocrystals which have the hydroxyl–pyridine synthon. The cocrystal forms were tested in accelerated ICH conditions of 40 °C and 75% RH for stability, a...

Aliphatic Dicarboxylate Directed Assembly of Silver(I) 1,3,5-Triaza-7-phosphaadamantane Coordination Networks: Topological Versatility and Antimicrobial Activity

Abstract: The present work describes the facile synthesis, full characterization, and architectural diversity of three new bioactive silver-organic networks, namely 1D [Ag2(μ-PTA)2(μ-suc)]n·2nH2O (1), 2D [Ag2(μ-PTA)2(μ4-adip)]n·2nH2O (2), and 3D [Ag2(μ4-PTA)(μ4-mal)]n (3) coordination polymers, generated via a mixed-ligand strategy using PTA (1,3,5-triaza-7-phosphaadamantane) as a main building block and flexible aliphatic dicarboxylic acids (succinic (H2suc), adipic (H2adip), or malonic (H2mal) acids) as an ancillary ligand source. The compounds 1–3 were isolated as moderately air and light stable crystalline solids and were fully characterized by IR and 1H and 31P{1H} NMR spectroscopy, elemental analysis, ESI(±)-MS spectrometry, and single-crystal X-ray crystallography. The type of aliphatic dicarboxylate plays a key role in defining the dimensionality and structural and topological features of the resulting networks, which are also driven by the PTA blocks that adopt unconventional N,P- or N3,P-coordination mode...

Synthesis and Characterization of Two Lanthanide (Gd3+ and Dy3+)-Based Three-Dimensional Metal Organic Frameworks with Squashed Metallomacrocycle Type Building Blocks and Their Magnetic, Sorption, and Fluorescence Properties Study

Abstract: Two novel isostructural lanthanide- based three-dimensional (3D) metal organic frameworks (MOFs), [Ln2(pam)3(DMF)2(H2O)2]n·nDMF {Ln = Gd(1), Dy(2); H2pam = 4,4′-methylenebis[3-hydroxy-2-naphthalenecarboxylic acid]} using the pharmaceutical agent “pamoic acid (H2pam)” are synthesized for the first time. Single crystal structure analysis shows that the 3D framework originates from the self-assembly of lanthanide metallomacrocycles made of dumble-shaped basic secondary building units and having channels of sizes 17.427 × 15.163 A (for 1) and 14.58 × 17.23 A (for 2), respectively. In both the complexes, two eight-coordinated lanthanide centers are connected with six pamoate groups to give a paddle-wheel type building block. The arrangement of pamoates and lanthanides in the framework provokes both right- (P) and left-hand (M) helicity around the 21 screw axis. The magnetic measurements show that complex 1 acts as a cryogenic magnetic refrigerant having magnetic entropy change, −ΔSm, of 17.25 J kg–1 K–1(ΔH = 7...

Reactivity of crystalline ZnO superstructures against fungi and bacterial pathogens: Synthesized using nerium oleander leaf extract

Abstract: For the first time, different morphologies of zinc oxide (ZnO) superstructures are synthesized by a simple and environmental friendly route using Nerium oleander leaf extract as fuel. Powder X-ray diffraction, scanning electron microscopy, UV–visible spectroscopy, and photoluminescence studies are performed to ascertain the formation and characterization of ZnO. X-ray diffraction confirmed the crystalline nature of the compound with hexagonal Wurtzite structure. When the concentration of the leaf extract is varied, different morphologies are formed. ZnO are tested for antifungal using soybean seed-borne fungi by food-poison method and antibacterial activity against bacterial human pathogens by a broth microplate dilution method using 96-well plates. Among the screened soybean seed-borne fungi, Fusarium equisiti was found to be more susceptible, which was followed by Macrophomina phaseolina for ZnO nanoparticles (NPs) prepared using 0.2188 mol/dm3 N. oleander leaf extract. It was observed that NPs exhibite...

Validation of a Computational Cocrystal Prediction Tool: Comparison of Virtual and Experimental Cocrystal Screening Results

Abstract: A virtual cocrystal screening method based on calculated gas phase molecular electrostatic potential surfaces (MEPS) of the individual components has been validated using experimental cocrystal screens reported in the literature. The noncovalent interactions of a molecule with its environment are described by a discrete set of independent surface site interaction points (SSIPs), whose properties can be calculated from the ab initio MEPS. The stability of a crystal is estimated based on pairing SSIPs such that the sum of the pairwise interaction energies is optimized. This provides a means of calculating the relative stability of a cocrystal compared with the pure components without knowing anything about the three-dimensional structures of the crystalline states. For a set of potential crystal coformers (CCF), the difference between interaction site pairing energies of different solid forms (ΔE) provides a method for ranking CCFs based on the calculated probability of cocrystal formation. The method was a...

Use of Continuous MSMPR Crystallization with Integrated Nanofiltration Membrane Recycle for Enhanced Yield and Purity in API Crystallization

Abstract: If continuous processing is to be employed in pharmaceutical production, it is essential that continuous crystallization techniques can meet the purity and yield achievable in current batch crystallization processes. Recycling of mother liquor in steady state MSMPR crystallizations allows the yield in the equivalent equilibrium batch process to be met or exceeded. However, the extent to which yield can be increased is limited by the buildup of impurities within the system. In this study, an organic solvent nanofiltration membrane was used to preferentially concentrate an API (deferasirox, M.W. = 373 Da) and purge the limiting impurity 4-hydrazinobenzoic acid (MW = 152 Da) from the mother liquor recycle stream in a mixed solvent (THF:ethanol) antisolvent (water) system. Incorporation of the membrane recycle allowed yields of 98.0% and 98.7% to be achieved. This compares to the following: a control MSMPR run without a membrane (70.3%), an equivalent batch process (89.2%), and the current commercial batch pr...

Designing Functional Metal–Organic Frameworks by Imparting a Hexanuclear Copper-Based Secondary Building Unit Specific Properties: Structural Correlation With Magnetic and Photocatalytic Activity

Abstract: In continuation of our research interest in pyrazole-based multifunctional metal organic frameworks (MOFs), we report here three Cu(II) MOFs using pyrazole and various aromatic carboxylic acid-based ligands. The main theme of interest is to design functional MOFs by imparting a multinuclear metal center as a secondary building unit (SBU). Accordingly, three MOFs are synthesized based on a hexanuclear Cu-pyrazolate unit as the SBU with some intriguing structural networks like (4,4) type herringbone grid or an archetypal Kagome topology. We have successfully synthesized functional MOFs by incorporating hexanuclear Cu-pyrazolate SBU-specific properties viz. magnetism and catalysis, the central theme of this work. All the MOFs show some photocatalytic degradation of toxic dye molecules. On the other hand, magnetic behaviors of MOF-2 and MOF-3 associated with the Cu6 unit have also been investigated.

Four Polyoxonibate-Based Inorganic–Organic Hybrids Assembly from Bicapped Heteropolyoxonibate with Effective Antitumor Activity

Abstract: Four novel heteropolyoxonibate-based inorganic–organic hybrids {Cu(en)2}6{GeNb12VIV2O42}·20H2O (1), {Cu(en)2}3K2Na4{GeNb12VIV2O42}·23H2O (2), {Cu(en)2}6{SiNb12VIV2O42}·18H2O (3), and {Cu(en)2}3K2Na4{SiNb12VIV2O42}·19H2O (4) (en = ethanediamine), composed of polyoxoanions [TNb12O40]16– (T = Si and Ge) and [Cu(en)2]2+ building blocks, were successfully synthesized under hydrothermal conditions by reaction of K7HNb6O19·13H2O, Cu(Ac)2·3H2O, Na2VO3, Na2SiO3, or GeO2 and en molecules. Polyoxoanion [TNb12VIV2O42]12– (T = Si and Ge) can be best described as a α-Keggin core [TNb12O40] with two [VO] units capping on its two “opened windows”. Compounds 1 and 3 are both composed of the bicapped heteropolyoxonibate core surrounded by a shell consisting of twelve [Cu(en)2]2+ groups, which represent a promising structural model toward core–shell nanostructures. Compounds 2 and 4 are also composed of a bicapped polyoxoanion [TNb12VIV2O42]12– (T = Si, Ge) decorated by three metal–organic fragments [Cu(en)2]2+, forming a t...