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Nowadays, exopolysaccharides (EPS) produced from bacterial cells are manufactured for their use in different industries in the world, mainly in the food, pharmaceutical, and wastewater industries. The characteristics of EPS, such as being biodegradable, safe, high adsorption capacity, and reusable, make them significant and potential applications in the purification of contaminated water of heavy metals. In this study, the possible application in biosorption Ni2+ ions from contaminated water was assessed using this exopolysaccharide as a biosorbent. The new exopolysaccharide from the bacterial strain K. oxytoca J7 was extracted, isolated, and characterized using SEM, FTIR, XRD, TGA/DTG, and MALDI-TOF MS analysis. Likewise, the cytotoxic activity was performed for EPS from K. oxytoca J7 strain. The aim of this study was to investigate the possible application of non-toxic exopolysaccharide in the purification of contaminated water by removing Ni2+ ions. The results obtained from the biosorption study showed that the Langmuir model is well suited to describe the adsorption process of Ni2+ ions by EPS from K. oxytoca J7, with a maximum adsorption capacity of 269.97 mg g–1. The importance of this study is the possible use of natural nontoxic exopolysaccharide extracted from the pathogen microorganism, K. oxytoca J7, for the removal of Ni2+ ions from the contaminated water. [ABSTRACT FROM AUTHOR]

In the search for environmentally friendly materials with a wide range of properties, polymer composites have emerged as a promising alternative due to their multifunctional properties. This study focuses on the synthesis of composite materials consisting of four components: bacterial nanocellulose (BNC) modified with magnetic Fe3O4, and a mixture of BaTiO3 (BT) and polyvinylidene fluoride (PVDF). The BT powder was mechanically activated prior to mixing with PVDF. The influence of BT mechanical activation and BNC with magnetic particles on the PVDF matrix was investigated. The obtained composite films' structural characteristics, morphology, and dielectric properties are presented. This research provides insights into the relationship between mechanical activation of the filler and structural and dielectric properties in the PVDF/BT/BNC/Fe3O4 system, creating the way for the development of materials with a wide range of diverse properties that support the concept of green technologies. [ABSTRACT FROM AUTHOR]

Two azo dye ligands, bearing different substituents (chlorine atom or methoxy group) in the para‐position of the phenyl ring, were employed for the synthesis of two Cu(II) chelates. Full structural affirmation of complexes was assessed. X‐ray diffraction measurements revealed that the coordination geometry for Cu atoms in both complexes is square‐pyramidal with a ligand:metal ratio of 2:1 where dyes behave as monobasic bidentate ligands. Thermogravimetric analyses of the complexes and their starting dyes were performed to study their thermal stabilities and decomposition behavior confirming the thermal stability of both dyes and complexes. Antioxidative activity of the complexes has been assigned and compared with their parent ligands revealing that the presence of the electron–donor, methoxy group, in the phenyl ring, in both dye and complex, is responsible for the activity (IC50 values of 1.54 for the dye and 1.30 mM for the complex). It should be stated that the complexation of the methoxy‐substituted dye leads to enhanced antioxidative activity concurrent to a standard antioxidant molecule of ascorbic acid, making this molecule a promising antioxidant agent. Docking study with vascular endothelial growth factor receptor 2 and Aurora kinase A proteins indicate that complexes exhibit higher binding affinities to proteins than the starting ligand dyes. The most promising structure exhibiting the best docking potential toward both proteins is the complex‐bearing methoxy group. The presented results represent a promising start for further investigations of these compounds as potential therapeutic candidates for the treatment of various types of cancer. [ABSTRACT FROM AUTHOR]

The present study describes representative examples of supramolecular arrangement of 5-phenylhydantoins achieved through various N–H⋯O hydrogen-bonding patterns. Four derivatives, 5-ethyl-5-(4-methylphenyl)hydantoin (1) and three 5-methyl-5-(3- or 4-substituted phenyl)hydantoins (2–4), were synthesized by the Bucherer–Bergs reaction and their crystal structures were determined by the single crystal X-ray diffraction method. A racemate, racemic hydrate and conglomerate as outcomes of crystallization from racemic solutions were found here. The crystal structures were firstly subjected to Hirshfeld surfaces analysis. The development of hydrogen bonding driven two-dimensional assemblies such as tapes, ribbons and sheets was further analysed using DFT calculations in terms of contribution of dimeric motifs as building blocks, which are associated with the presence of intermolecular interactions. To explore qualitative correlations between intermolecular interactions determining the crystal structures of the investigated compounds and those underlying their biological activity, we performed a docking study on the neuronal voltage gated sodium channels, matrix metalloproteinase 12 and aldose reductase. The supramolecular profiles of the investigated compounds are also maintained in biological systems and as such are responsible for differences in their biological activities. [ABSTRACT FROM AUTHOR]

Two spirohydantoin derivatives, 3-(4-chlorobenzoyl)-1,3-diazaspiro[4.5]decane-2,4-dione (1) and 3-(4-bromobenzoyl)-1,3-diazaspiro[4.5]decane-2,4-dione (2), were synthesized and analyzed by single crystal X-ray diffraction, DFT and QTAIM calculations. Simple substitution of the benzoyl unit gave rise to different crystal structures. In 1, a parallel stack along the b-axis with alternating perpendicular separation is formed, while in 2 the R 46 (32) nets are joined together to form stacks which enclose linear channels. Hierarchical development of these crystal structures was analyzed through dimeric motifs associated with the presence of intermolecular interactions. By including the previously reported structurally-related spirohydantoin derivatives, we created a set of structures which enabled us to evaluate substituent effects on their conformational preferences, i.e., widening of the dihedral angle between the hydantoin and substituted benzoyl unit when going from F to Br. A conformational search revealed that the value of the torsion angle N3–C11–C12–C13 can be regarded as a compromise between the extended conjugation between the carbonyl and phenyl group and intramolecular C–H⋯O interaction between these two groups. This intramolecular effect is more pronounced on the torsion angle C2–N3–C11–C12, which defines the relative orientation between the hydantoin ring and the carbonyl bridge. The present work may provide a basis for design of new cyclohexane-5-spirohydantoins with potential for pharmaceutical applications both at the molecular and supramolecular level. [ABSTRACT FROM AUTHOR]

The quantitative assessment of intermolecular interactions and their cooperative effects has been performed in spirohydantoin-based model compounds, 3-benzoyl-1,3-diazaspiro[4.5]decane-2,4-dione (1) and 3-(4-fluorobenzoyl)-1,3-diazaspiro[4.5]decane-2,4-dione (2), through single crystal X-ray crystallography and quantum chemical studies. In both crystal structures, molecules generate the same hydrogen-bonded centrosymmetric R 22 (8) synthon. The extended supramolecular architectures depend on the C–H⋯O, C–H⋯π, stacking interactions and parallel interactions at large offsets, which lead to molecular sheets and further, with the assistance of the C–H⋯F interaction in the case of 2, to three-dimensional networks. Electrostatic potential maps have indicated that formation of the intermolecular F⋯F interaction in the crystal structure of 2 results in a new region with a larger surface area and a higher negative potential in comparison to the individual fluorine atoms. Establishment of this interaction leads to strengthening of the interaction of one of the fluorine atoms with a third molecule from the environment which does not interact with both of them. When this third molecule interacts with both fluorine atoms simultaneously, the calculations have shown that the effect of strengthening of the individual interactions due to formation of the F⋯F interaction is absent. [ABSTRACT FROM AUTHOR]

A racemic spirohydantoin derivative with two aromatic substituents, a tetralin and a 4‐methoxybenzyl unit, was synthesized and its crystal structure was determined. To define the relationship between molecular stereochemistry and spatial association modes, development of the crystal packing was analyzed through cooperativity of intermolecular interactions. Homo and heterochiral dimeric motifs were stabilized by intermolecular N−H⋅⋅⋅O, C−H⋅⋅⋅O, C−H⋅⋅⋅π interactions and parallel interactions at large offsets (PILO), thus forming alternating double layers. The greatest contribution to the total stabilization came from a motif of opposite enantiomers linked by N−H⋅⋅⋅O bonds (interaction energy=−13.72 kcal/mol), followed by a homochiral motif where the 4‐methoxybenzyl units allowed C−H⋅⋅⋅π, C−H⋅⋅⋅O interactions and PILO (interaction energy=−11.56 kcal/mol). The number of the contact fragments in the environment of the tetralin unit was larger, but the 4‐methoxybenzyl unit had greater contribution to the total stabilization. The statistical analysis of the data from the Cambridge Structural Database (CSD) showed that this is a general trend. The compound is a potential inhibitor of kinase enzymes and antigen protein‐coupled receptors. A correlation between the docking study and the results of the CSD analysis can be drawn. Due to a greater flexibility, the 4‐methoxybenzyl unit is more adaptable for interactions with the biological targets than the tetralin unit. [ABSTRACT FROM AUTHOR]

Ten 5‐(substituted phenylazo)‐3‐cyano‐1‐ethyl‐6‐hydroxy‐4‐methyl‐2‐pyridones were studied (five new compounds) to provide insight into the electronic effects of diverse substituents located at different positions in their phenyl moieties. The structural features of these dyes were examined by combining experimental and theoretical approaches. The crystal structures of two derivatives were revealed by X‐ray crystallography and diverse packing modes owing to different intermolecular interactions (π–π stacking and lone pair–π interactions, as well as hydrogen bonds) were found. A study on lattice energy and energy related to the molecular pairs obtained from their crystal packing was performed. The tautomerism and ionisation of the dyes in ethanol or N,N ‐dimethylformamide solution were rationalised in terms of diazo component substitution pattern. [ABSTRACT FROM AUTHOR]

ABSTRACT Two series of semiinterpenetrating networks (SIPN) based on linear hydrophilic poly(vinyl alcohol) (PVA) and thermo-responsive poly( N-isopropylacrylamide) (PNIPA), physically crosslinked with inorganic clay, are presented. The hydrogels with different crosslinking densities were prepared by varying the content of clay from 1 to 6 wt % and contained linear interpenetrant, PVA in the range of 0.5-1.5 wt %. The effect of clay content on swelling/deswelling behavior and phase transition in PNIPA gels, as well as the feasibility of reinforcing the gels with high molecular weight PVA, were analyzed. The thermal response of hydrogels, followed by DSC, confirmed that the insertion of hydrophilic PVA did not have a significant effect on the onset of the volume phase transition temperature, while the response was faster. The equilibrium degree of swelling of SIPNs and PNIPA hydrogels was in the range of 9-79 and decreased with increasing content of clay. The internal morphology and surface wettability of the hydrogels were investigated by scanning electron microscope analysis and contact angle measurements, respectively. The network structural parameters of the PNIPA and SIPN nanocomposites hydrogels, such as the average molecular weight between crosslinks, Mc, and effective crosslinking density, Ne, were determined by dynamic mechanical analysis. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44535. [ABSTRACT FROM AUTHOR]

A series of cycloalkane-5-spirohydantoins bearing a halogeno substituted benzyl group (X = Cl and Br) in position 3 has been synthesized and their structures (1–6) have been determined by a single crystal X-ray diffraction method. These compounds have multiple functional groups, which allow greater competition and/or cooperation among the different intermolecular interactions in the formation of their crystal structures. The molecules are linked together by paired N–H…O hydrogen bonds in R22(8) rings, while the C–H…O interactions lead to their further association into double chains. The contribution of the cycloalkyl ring depends on its conformational flexibility and the multiple C–H donor implications. In the case of compounds 1–4 bearing the cyclopentyl or the cyclohexyl ring, halogen bonding (X…O) interactions give rise to a supramolecular pseudo-hexagonal network. In addition, the C–H…X interactions with a higher degree of multifurcation at the halogen acceptor have an important role in the formation of the crystal structure. Regarding compounds 5 and 6 with the cycloheptane ring, the X…O interaction is absent, and along with the C–H…X interactions, these compounds realize an alternative crystal structure with an emphasis on the X…π interactions. The lattice energies of all these crystal structures, as well as the intermolecular pair energies, have been calculated using PIXEL and further partitioned into coulombic, dispersive, polarization and repulsive factors. The crystal structures have also been subjected to Hirshfeld surface analysis which reveals that approximately 75% of the close contacts correspond to relatively weak interactions. The application of both concepts has provided a new insight into the relationship between the molecular interactions and crystal structures of the hydantoin derivatives. [ABSTRACT FROM AUTHOR]

Natural (SEP) and partially acid-activated (AAS) sepiolites were used to prepare composites with nanoscale zerovalent iron (nZVI) at different (SEP or AAS)/nZVI ratios in order to achieve the best nZVI dispersibility and the highest adsorption capacity for Cd. Despite the higher surface area and pore volume of AAS, better nZVI dispersibility was achieved by using SEP as the support. On the other hand, a lower oxidation degree was achieved during the synthesis using AAS. X-ray photoelectron spectroscopy (XPS) analysis of the composite with the best nZVI dispersibility, before and after Cd adsorption, confirmed that the surface of the nZVI was composed of oxidized iron species. Metallic iron was not present on the surface, but it was detected in the subsurface region after sputtering. The content of zerovalent iron decreased after Cd adsorption as a result of iron oxidation during Cd adsorption. The XPS depth profile showed that cadmium was present not only at the surface of the composite but also in the subsurface region. The adsorption isotherms for Cd confirmed that the presence of SEP and AAS decreased the agglomeration of the nZVI particles in comparison to the pure nZVI, which provided a higher adsorption capacity. The results showed that the prevention of both aggregation and oxidation during the synthesis was necessary for obtaining an SEP/AAS-nZVI composite with a high adsorption capacity, but oxidation during adsorption was beneficial for Cd removal. The formation of strong bonds between Cd and the adsorbents sites of different energy until monolayer formation was proposed according to modeling of the adsorption isotherms. [ABSTRACT FROM AUTHOR]

Pt nanoparticles supported on Vulcan XC-72R were synthesized by water-in-oil microemulsion method. By incorporating different amounts of HCl as a capping agent in the precursor-containing water phase, nanoparticle shape was varied. Influencing the growth of certain facets leads to the changes of the particle shape depending on the preferential facets. As a result, nanoparticles exhibit some of the electrochemical features typical for single crystals. Commonly employed synthesis procedure for water-in-oil microemulsion method was altered with the addition of catalyst support in the system and changing the catalyst cleaning steps. Prepared catalysts were characterized by thermogravimetric analysis (TGA), transmission electron microscopy (TEM) and electrochemical methods. Activity and stability for methanol oxidation reaction (MOR), a structure-sensitive reaction, were tested. Electrochemical results reveal the influence of particle size, shape and exposed facets on the electrochemical processes. TEM investigations confirm electrochemical findings, while TGA verifies Pt loading in catalyst powder. Based on the results, optimal HCl concentration for cubic particle formation is determined, and structural effect on MOR activity and stability was tested. Cuboidal NPs show very good reaction activity and fair stability under applied experimental conditions. [ABSTRACT FROM AUTHOR]

In search of novel photoactive liquid crystals, we have synthesized a series of five-ring pyridine-based bent-core compounds bearing different substituents at the peripheral phenyl rings (CH3O, Cl and NO2). Their mesomorphic behaviour has been investigated by polarizing optical microscopy, differential scanning calorimetry and X-ray scattering, and then compared with the unsubstituted parent compound. The introduction of the methoxy groups at the peripheral phenyl rings of the bent core results in a non-mesomorphic compound, whereas the chloro- and nitro-substituted compounds form enantiotropic B1-like phases. Significant changes in the textures and transition temperatures of the mesophase have been observed under UV light. The present investigation of the mesomorphic properties of the synthesized compounds, coupled with the analysis of the molecular packing of the related three-ring compounds, will help design self-organized molecules suitable for UV indicators. [ABSTRACT FROM AUTHOR]

The preparation of epoxy/clay nanocomposites (NCs) and their insertion into coatings are of great importance since the NCs could enhance the protective performances. In this study, epoxy NCs with 1-10 wt% of nanoclay Cloisite 30B (C30B) were prepared by the sonication-assisted solution method. The rheological measurements of epoxy/C30B suspensions revealed non-Newtonian, shear-thinning behavior of the uncured NCs, with an increase in the viscosity, yield stress, and shear modules with increasing organoclay content, while the dispersion effectiveness of C30B decreased. A significant enhancement of the rheological parameters was observed at the second percolation threshold (4.1 vol%) due to the formation of a continuous network of 45-layer-thick tactoids. Although NCs with 1-3 wt% C30B exhibited slightly reduced mechanical and adhesion properties compared with the cured reference epoxy resin, the epoxy primer and topcoat based on NC with 1 wt% C30B generally displayed improved impact resistance and maintained flexibility, pendulum hardness, and good adhesion properties. Two-layer coating systems, i.e., NC-based primers and topcoats, had higher corrosion stability in a salt spray chamber compared to the unmodified system. [ABSTRACT FROM AUTHOR]

Two series, one of triblock (PCL/PEO/PCL) and the other of diblock (PCL/PEO) copolymers were prepared by ring-opening polymerization of ε-caprolactone catalized with tin(II) octoate and by using dihydroxy or monohydroxy poly(ethylene oxide) as the macroinitiator. The PEO block length was fixed ( M 1,000 g/mol) and the PCL block lengths ( M 10,000-40,000 g/mol) were tailored by changing weight ratio of ε-CL/PEO. The copolymers' structure was confirmed by H and quantitative C NMR spectroscopy while their molecular weights were determined by GPC analysis. The thermal properties and the degree of crystallinity of the copolymers were investigated and compared by using DSC and WAXS. Both types of copolymers were semicrystalline with the orthorhombic PCL crystal lattice. The surface morphology of the copolymer films was investigated by using optical microscopy and AFM analysis, which confirmed the spherulitic lamellar structure with spherulites of different diameters. Data indicated that a low content of PEO segment had an influence on thermal degradation behavior, crystallinity and morphology of copolymers. Roughness of copolymer films was affected by the content of PEO and correlated with the spherulites' diameter. The small changes in water and moisture absorption properties of copolymers compared to homopolymer PCL were observed. [ABSTRACT FROM AUTHOR]

Thermal degradation of ternary transition metal complex containing tetraanion of pyromellitic acid, pyr, and ethylenediamine, en, [Ni( en)(HO)( pyr)]·4HO, 1, was investigated under non-isothermal conditions. The mechanism of thermal degradation, which occurs in three steps, was clarified by TG/DSC measurements in conjunction with FT-IR spectroscopy and XRPD analysis. The complexity of all degradation steps has been revealed using isoconversional methods. Dehydration comprises the loss of ten water molecules in a relatively narrow temperature interval, resulting in a very complicated reaction mechanism. In addition, density functional theory calculations have been applied for better understanding of dehydration. The second degradation step, related to loss of en, was separated into two single-step processes with Fraser-Suzuki function. The obtained individual steps were described by Johnson-Mehl-Avrami A2 model and Šesták-Berggren model, respectively. Validation of the proposed kinetic triplets for individual steps was performed using master plot and Pérez-Maqueda criteria. The third degradation step is related to the fragmentation of pyr ion most likely followed with the release of a number of gaseous products. [ABSTRACT FROM AUTHOR]

The presented study investigates solidification/stabilization process of hazardous heavy metals/arsenic sludge, generated after the treatment of the wastewater from a primary copper smelter. Fly ash and fly ash with addition of hydrated lime and Portland composite cement were studied as potential binders. The effectiveness of the process was evaluated by unconfined compressive strength (UCS) testing, leaching tests (EN 12457-4 and TCLP) and acid neutralization capacity (ANC) test. It was found that introduction of cement into the systems increased the UCS, led to reduced leaching of Cu, Ni and Zn, but had a negative effect on the ANC. Gradual addition of lime resulted in decreased UCS, significant reduction of metals leaching and high ANC, due to the excess of lime that remained unreacted in pozzolanic reaction. Stabilization of more than 99% of heavy metals and 90% of arsenic has been achieved. All the samples had UCS above required value for safe disposal. In addition to standard leaching tests, solidificates were exposed to atmospheric conditions during one year in order to determine the actual leaching level of metals in real environment. It can be concluded that the EN 12457-4 test is more similar to the real environmental conditions, while the TCLP test highly exaggerates the leaching of metals. The paper also presents results of differential acid neutralization (d-AN) analysis compared with mineralogical study done by scanning electron microscopy and X-ray diffraction analysis. The d-AN coupled with Eh-pH (Pourbaix) diagrams were proven to be a new effective method for analysis of amorphous solidified structure. [ABSTRACT FROM PUBLISHER]

The novel polymeric complexes catena-poly[[diaquamanganese(II)]-μ-2,2′-bipyrimidine-κ4 N1, N1′: N3, N3′-[diaquamanganese(II)]-bis(μ-terephthalato-κ2 O1: O4)], [Mn2(C8H4O4)2(C8H6N4)(H2O)4] n, (I), and catena-poly[[[aquacopper(II)]-μ-aqua-μ-hydroxido-μ-terephthalato-κ2 O1: O1′-copper(II)-μ-aqua-μ-hydroxido-μ-terephthalato-κ2 O1: O1′-[aquacopper(II)]-μ-2,2′-bipyrimidine-κ4 N1, N1′: N3, N3′] tetrahydrate], {[Cu3(C8H4O4)2(OH)2(C8H6N4)(H2O)4]·4H2O} n, (II), containing bridging 2,2′-bipyrimidine (bpym) ligands coordinated as bis-chelates, have been prepared via a ligand-exchange reaction. In both cases, quite unusual coordination modes of the terephthalate (tpht2−) anions were found. In (I), two tpht2− anions acting as bis-monodentate ligands bridge the MnII centres in a parallel fashion. In (II), the tpht2− anions act as endo-bridges and connect two CuII centres in combination with additional aqua and hydroxide bridges. In this way, the binuclear [Mn2(tpht)2(bpym)(H2O)4] entity in (I) and the trinuclear [Cu3(tpht)2(OH)2(bpym)(H2O)4]·4H2O coordination entity in (II) build up one-dimensional polymeric chains along the b axis. In (I), the MnII cation lies on a twofold axis, whereas the four central C atoms of the bpym ligand are located on a mirror plane. In (II), the central CuII cation is also on a special position (site symmetry ). In the crystal structures, the packing of the chains is further strengthened by a system of hydrogen bonds [in both (I) and (II)] and weak face-to-face π-π interactions [in (I)], forming three-dimensional metal-organic frameworks. The MnII cation in (I) has a trigonally deformed octahedral geometry, whereas the CuII cations in (II) are in distorted octahedral environments. The CuII polyhedra are inclined relative to each other and share common edges. [ABSTRACT FROM AUTHOR]

Two new series of hydantoin derivatives, 3-(4-substituted benzyl)-5,5-diphenyl- and 3-(4-substituted benzyl)-5-ethyl-5-phenylhydantoins, were synthesized and their antiproliferative activity was tested against human colon cancer HCT-116 and breast cancer MDA-MB-231 cell lines. The presence of different substituents on both hydantoin and benzyl moieties changed the antiproliferative activity of the investigated hydantoins, whereby most of the compounds showed superior antiproliferative activity against MDA-MB-231 than against the HCT-116 cell line. The structure of three compounds was studied by single-crystal X-ray diffraction. The general structural characteristic is the presence of N-H···O hydrogen bonds in crystal packings. The molecular geometry and bonding features of the investigated hydantoins in the ground states were calculated using the density functional method. The relationship between structure and antiproliferative activity was discussed. The data presented in this investigation afford guidelines for the preparation of new hydantoin derivatives with greater antiproliferative activity. Graphical Abstract: [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

Segmented poly(urethane-urea-siloxane)s (PUUS) were synthesized using 4,4′-methylenediphenyl diisocyanate (MDI) and ethylene diamine (ED) as the hard segment components and hydroxypropyl-terminated poly(dimethylsiloxane) (PDMS) as the soft segment component, where the hard segment content ranged from 38 to 65 wt%. Segmented PUUSs were prepared by a two-step polymerization procedure in tetrahydrofuran/ N-methylpyrrolidone (THF/NMP) mixture with a large proportion of polar solvent. The structure, composition and hard segment length were determined by C NMR and two-dimensional correlation spectroscopy. Thermal, mechanical, small-angle X-ray scattering and hydrogen bonding analyses indicated the formation of the microphase-separated copolymers with high tensile strength. Globular superstructures observed in the copolymer films by scanning electron microscopy (SEM) and atomic force microscopy (AFM) were probably arisen from the microstructural organization of the MDI-ED segments, depending on their content and length. The PUUS copolymers showed high water resistance and became more hydrophobic with increasing weight fraction of PDMS. [ABSTRACT FROM AUTHOR]

The title compound, Rb2[Co(H2O)6](C8H5O4)4·4H2O, consists of nearly regular octahedral [Co(H2O)6]2+ cations with the CoII cations on the inversion centre (special position 2 a), Rb+ cations, hydrogen phthalate (Hpht−) anions and disordered water molecules. The Rb+ cation is surrounded by nine O atoms from Hpht− anions and water molecules, with a strongly deformed pentagonal-bipyramidal geometry and one apex split into three positions. The crystal packing is governed by numerous hydrogen bonds involving all water molecules and Hpht− anions. In this way, layers parallel to the ab plane are formed, with the aromatic rings of the Hpht− anions esentially directed along the c axis. While Hpht− anions form the outer part of the layers, disordered water molecules and Rb+ cations alternate with [Co(H2O)6]2+ cations in the inner parts. The only interactions between the layers are van der Waals forces between the atoms of the aromatic rings. A search of the Cambridge Structural Database for coordination modes and types of hydrogen-bonding interaction of the Hpht− anion showed that, when uncoordinated Hpht− anions are present, compounds with intermolecular hydrogen bonds are more numerous than compounds with intramolecular hydrogen bonds. For coordinated Hpht− anions, chelating and bridging anions are almost equally common, while monodentate anions are relatively scarce. The same coordination modes appear for Hpht− anions with or without intramolecular hydrogen bonds, although intramolecular hydrogen bonds are less common. [ABSTRACT FROM AUTHOR]

Considering the importance of hydantoin derivatives in treatment of status epilepticus, four 5-phenylhydantoins, whose lipophilicities were estimated to be similar to that of phenytoin, were synthesized. Evaluation of their anticonvulsant activities was performed on rats by subcutaneous pentylenetetrazol seizure test and intravenous pentylenetetrazol threshold test, and spontaneous locomotor activity test was used to assess possible sedative effects. X-ray analysis of three compounds suggested that certain analogies might be drawn between interactions in crystal packing and biological interactions responsible for their anticonvulsant activity. It was found that 5-ethyl-5-phenyl-3-propylhydantoin exhibits the most favorable pharmacological properties among the synthesized compounds, i.e., anticonvulsant activity comparable to phenytoin with lower liability for induction of sedation in rats. Graphical Abstract: [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]

The article discusses a study on coordination polymer in the title as to structural diversity of the compounds and potentials. The N atoms and 3 O atoms from a di-2-pyridylamine (dipya) ligand formed a distorted pyramidal geometry of the CuII cation with the zigzag chains on the β axis. Findings indicated that metal-organic polymers are rare when benzene-1,3-dicarboxylate (ipht) is coordinated as bridging tridentate ligand with chelate and monodentate caboxylate.

The title complexes, catena-poly[[aqua(1,10-phenanthroline-κ2 N, N′)­cobalt(II)]-μ-benzene-1,4-di­carboxyl­ato-κ2 O1: O4], [Co(C8H4O4)(C12H8N2)(H2O)], (I), and catena-poly[[[(di-2-pyridyl-κ N-amine)copper(II)]-μ-benzene-1,4-di­carboxyl­ato-κ4 O1, O1′: O4, O4′] hydrate], [Cu(C8H4O4)(C10H9N3)]·H2O, (II), take the form of zigzag chains, with the 1,4-benzene­di­carboxyl­ate ion acting as an amphimonodentate ligand in (I) and a bis-bidentate ligand in (II). The CoII ion in (I) is five-coordinate and has a distorted trigonal-bipyramidal geometry. The CuII ion in (II) is in a very distorted octahedral 4+2 environment, with the octahedron elongated along the trans O-Cu-O bonds and with a trans O-Cu-O angle of only 137.22 (8)°. [ABSTRACT FROM AUTHOR]