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Theincorporation of nanoparticles into polymer represents a fundamentalpathway in the development of reinforced composites. Inspired by rigidcellulose nanocrystals (CNCs), a simple and robust approach for thefabrication of tough and stretchable hydrogels was proposed that basedon the incorporation of a three-dimensional CNC template. By mimickingthe hierarchical cork structure, the obtained composite hydrogelswith a binary network can sustain structural integrity under a loadof 12 000-time of the template weight and recover from >85%tensile compression. Analysis of toughening mechanisms reveals twostrategies, template pullout and polymer chain sacrificial bonds,that synergistically corroborate the materials integrity to largedeformations. First, the embedded CNC template splayed among neighboringfibrils and bridged crack continuously, which entailed the efficientenergy dissipation via strong hydrogen interactions between packedCNC walls without comprising the template integrity. Second, the hydrophobiccoiled micelles unraveled and acted as sacrificial bonds to dissipateenormous amount of energy upon being stretched. This versatile approachopens up a new opportunity to highlight the multifunctionality ofCNC as an indicator for designing of advanced cellulosic nanocompositeswith improved mechanical properties from incompatible components. [ABSTRACT FROM AUTHOR]

Although a variety of functional metal-organic frameworks (MOFs) have been synthesized, post-modified, and applied in various areas, there is little knowledge about how molecular cluster building units are stepwise evolved into MOFs via intermediates. Coordination bonds are generally stronger than hydrogen bonds, and thus equivalent replacement of X-H···Y hydrogen bonds by X-M-Y coordination bonds can transform hydrogen bond networks into MOFs. In this work, solvothermal in situ reduction reactions of CuBr2 and 1,4-diazoniabicyclo[2,2,2]octane (DABCO) generated a myriad of tunable photoluminescent cuprous body-centered cubic bromide cluster-based networks with the general formula [Cu4+xH4-xBr6(DABCO)4](HCO2)2·S (x = 0, 0.56, 0.81, 1.27, 1.39, 2.56, 2.78, and 4 for compounds 1-8, respectively). All of these compounds crystallize in the cubic space group with the largest volume difference being only 5.2%, but they belong to three remarkably different kinds of crystals. Complex 1 is a molecular crystal and consists of tetrahedral [Cu4Br6(HDABCO)4]2+ clusters with monodentate HDABCO groups that are supported via N-H···Br synthons in the hydrogen bond network. Compound 8 is a [Cu8Br6]2+ cube cluster-based MOF with bridged DABCO ligands. Complexes 2-7 are seemingly impossible Cu/H-substituted solid solutions of 1 and 8. The CuBr framework components in 1-8 are Cu4Br6, Cu4.56Br6, Cu4.81Br6, Cu5.27Br6, Cu5.39Br6, Cu6.56Br6, Cu6.78Br6, and Cu8Br6, respectively. Crystallization kinetics studies revealed that the [Cu4Br6(HDABCO)4]2+ cluster-based hydrogen bond network (1) was initially formed such that N-H···Br hydrogen bonds could be stepwise replaced by N-Cu-Br coordination bonds to form the [Cu8Br6]2+ cube cluster-based MOF (8) via solid solutions. These observations directly reveal the equivalence and transformation between the N-H···Br hydrogen bond and the N-Cu-Br coordination bond and the evolutionary mechanism of a molecular crystal to a MOF via solid solutions, which is of fundamental importance in materials but has never before been revealed. DFT calculations suggest that equivalent replacement of a N-H···Br hydrogen bond by a N-Cu-Br coordination bond is exothermic and exergonic, which also supports the transformation from molecule 1 to MOF 8. [ABSTRACT FROM AUTHOR]

To probe the detailed structure of dextran hydrogels, periodical models for three dextran hydrogel systems with different dextran contents have been constructed and compared using molecular dynamic simulations. The software packages of Amorphous and Discover in Material Studio with COMPASS force field were used for the simulation. Energy minimization and geometry optimization were used to refine the models. In particular, the structure and dynamic movement of dextran chains which impose on water in the dextran hydrogel systems have been studied. The results show that in the physically crosslinked dextran hydrogels, KCl served as the crosslinker and it interacted with dextran via the oxygen atoms of hydroxyl groups in dextran ring. With increasing dextran content, the free volumes of the hydrogels and the diffusion coefficients of water in the hydrogel decrease. By the radial distribution analysis, the water in the hydrogel networks was found to interact with dextran via hydrogen bond and there are at least three kinds of water in the physically crosslinked dextran hydrogels. These results have a great significance for understanding the structure and properties of the hydrogel. [ABSTRACT FROM AUTHOR]

This review covers advances in the non-cyclizing direct transformations of arene carbon--hydrogen bonds into carbon--nitrogen bonds, including carbon--nitrogen bond formations for arenes bearing directing groups, for polyfluoroarenes, and for alkyl-substituted arenes. Copper catalysis, palladium catalysis and metal-free strategies for carbon--nitrogen bond formation are discussed. 1 Introduction 2 Carbon--Nitrogen Bond Formation for Arenes Bearing Directing Groups 3 Carbon--Nitrogen Bond Formation for Polyfluoroarenes 4 Carbon--Nitrogen Bond Formation for Alkyl-Substituted Arenes 5 Conclusion [ABSTRACT FROM AUTHOR]

A series of thiosemicarbazone derivatives of benzo-15-crown-5 were synthesized efficiently at room temperature using hydrogenchloride acid (HCl) as catalyst. Their anion recognition properties of a, b and c were studied, the result show they exhibit highly selective binding and sensing of F-, MeCO2- and n-C3H7CO2- in CH3CN (F- > n-C3H7CO2- > MeCO2- > > Cl-, Br- and I-). Especially receptor c shows different UV-Vis spectrum of F- from MeCO2-and C3H7CO2-, in addition to the color of the solution change from colorless to yellow upon the addition of F-, these two points make it suitable to be used as colorimetric anion sensor to identify fluoride anion from other halide anions and carboxylate anions by naked-eye. The connection between receptor and anion is by hydrogen bonding interactions, the binding ratio is 1:1, which have been confirmed by UV-vis inspection spectra in CH3CN and 1HMR in DMSO-d6. [ABSTRACT FROM AUTHOR]

In the title compound, [Ni(C8H5N4O2)2(H2O)4]·2H2O, the NiII ion lies on an inversion centre and is coordinated by two N atoms from two 4-(tetrazol-1-yl)benzoate ligands and four O atoms from four water molecules in a slightly distorted octahedral geometry. In addition, there are two uncoordinated water molecules in the structure. The crystal structure is stabilized by intermolecular O—H⋯O hydrogen bonds. [ABSTRACT FROM AUTHOR]

Two kinds of N-ethoxycarbonyl-N′-arylthiourea were synthesized, and their structure was determined by X-ray diffraction. There are inter-and intramolecular hydrogen bonds in these compounds. In the crystals, the compounds were assembled to one-dimensional catenulate supramolecular structure by intermolecular hydrogen bonds. [ABSTRACT FROM AUTHOR]

Abstract: Adsorption of phenol from aqueous solution onto a nonpolar adsorbent, aminated adsorbent and weak base adsorbent (Amberlite XAD4, NDA103 and Amberlite IRA96C, respectively) at temperatures from 293 to 313K was studied for the weak interactions between the phenol molecules and the polymeric adsorbents. Isotherms of Langmuir and Freundlich equation with characteristic parameters for different adsorbents were well fitted to the batch equilibrium adsorption data. The adsorption capacity on NDA103 driven by hydrogen bonding and van der Waals interaction together is higher than that on IRA96C driven by hydrogen bonding interaction only and on XAD4 driven by van der Waals interaction only. For evaluating synergistic adsorption for phenol–water systems onto polymeric adsorbents, the adsorption capacity is normalized to the amounts of specific surface area and amino groups of adsorbents. The synergistic effect with other weak interactions would contribute more to the adsorption as acting simultaneously than that of acting individually. [Copyright &y& Elsevier]

The adsorption behaviors of phenol and aniline on nonpolar macroreticular adsorbents (NDA100 and Amberlite XAD4) were investigated in single or binary batch system at 293K and 313K respectively in this study. The results indicated that the adsorption isotherms of phenol and aniline on both adsorbents in both systems fitted well Langmuir equation, which indicated a favourable and exothermic process. At the lower equilibrium concentrations, the individual amount adsorbed of phenol or aniline or macroreticular adsorbents in single-component systems was higher than those in binary-component systems because of the competition between phenol and aniline towards the adsorption sites. It is noteworthy, on the contrast, that at higher concentrations, the total uptake amounts of phenol and aniline in binary-component systems were obviously larger than that in single-component systems, and a large excess was noted on the adsorbent surface at saturation, which is presumably due to the cooperative effect primarily arisen from the hydrogen bonding or weak acidbase interaction between phenol and aniline. [ABSTRACT FROM AUTHOR]

A novel organic-templated zincophosphate, namely (C6H16N2)[Zn(HPO4)2], was hydrothermally synthesized and X-ray single-crystal structural analysis reveals that the anions [Zn(HPO4)2]2–, which have square-twisted chains containing corner-sharing four-rings of alternating ZnO4 and PO4 tetrahedra, are assemblied via self-complementary strong and symmetrical hydrogen-bonding R22(8) synthons between the phosphate groups into three-dimensional hydrogen bond frameworks featuring three-dimensional intersecting pseudochannels. The doubly protonated 2,5-dimethylpiperazinium cations are attached to the three-dimensional inorganic framework via N-H···O hydrogen bonds to strengthen the 3-D network. [ABSTRACT FROM AUTHOR]

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The title Schiff base compound, C12H17NO3, synthesized by the reaction of paeonol and isopropanolamine in absolute methanol, crystallizes in a zwitterionic form. All non-H atoms, except for the 2-hydroxy­propyl group, are approximately coplanar. The mol­ecules are linked to each other by intermolecular hydrogen bonds. [ABSTRACT FROM AUTHOR]

In the crystal structure of the title compound, [Cu(ClO4)(C22H17ClN2)(C6H18N4)]ClO4, the CuII ion assumes a distorted octa­hedral coordination geometry. [ABSTRACT FROM AUTHOR]

In the title Schiff base complex, [ZnCl2(C10H12NO2)2], the ZnII ion is in a distorted tetra­hedral ZnO2Cl2 coordination environment. [ABSTRACT FROM AUTHOR]

The title compound, C5H9ON3, was synthesized by the reaction of 2-hydrazinylethanol with 3-methoxy­propane­nitrile. The pyrazole ring system is essentially planar. Molecules are linked by O—H⋯N and N—H⋯O hydrogen bonds. [ABSTRACT FROM AUTHOR]

The title centrosymmetric dinuclear complex, [Co2(C7H3NO4)2(C10H8N2)(H2O)6]·2H2O, has been synthesized hydro­thermally. The cobalt(II) ion is coordinated in a slightly distorted octa­hedral environment by one N atom and one carboxylate O atom in N, O-chelating mode from one 2,4-pyridine­dicarboxyl­ate ligand, by one N atom from 4,4′-bipyridine, and by three water mol­ecules. O—H⋯O hydrogen bonds link mol­ecules into a three-dimensional framework. [ABSTRACT FROM AUTHOR]

The dinuclear cation of the title compound, [Mn2Cl2(C2H8N2)4]Cl2, has the Cl atoms bridging the ethane-1,2-di­amine-chelated Mn atoms across a centre of inversion. The cations are linked to the chloride anions by hydrogen bonds, forming a three-dimensional network. [ABSTRACT FROM AUTHOR]

In the crystal structure of the title compound, [Zn (C12H8N2)(C3H5O5P)(H2O)2]·2H2O, the zinc atom is five-coordinate in a trigonal bipyramidal N2O3Zn environment; the apical sites are occupied by the aqua ligand and the N atom of the heterocycle. Hydro­gen bonds link the zwitterions and lattice water mol­ecules into a three-dimensional network motif. [ABSTRACT FROM AUTHOR]

In the title compound, [Ni(C7H19N3O)2](ClO4)2, the Ni atom, which is located on an inversion center, is hexacoordinated by six N atoms from two ligands, forming a distorted octahedron. The complex molecules are linked by N—H...O hydrogen bonding, forming a one-dimensional chain structure along the a axis, which is further hydrogen bonded with the perchlorate anion to form a three-dimensional framework. One —CH2—CH2— group is disordered over two positions; the site occupancy factors are ca. 0.6 and 0.4. [ABSTRACT FROM AUTHOR]

In the title compound, C3H6N2O2S, the five-membered ring has an envelope conformation and the two hydroxyl groups lie on opposite sides of the ring. The crystal structure is stablized by intermolecular O—H...S and N—-H...O hydrogen bonds, and also a close O...O intermolecular approach, to form a two-dimensional network parallel to bc. [ABSTRACT FROM AUTHOR]

In the title compound, C21H32N2OS2, the cyclohexene and cyclopentane rings adopt envelope conformations, while the cyclohexane rings are in chair conformations. The molecules are linked into a zigzag chain along the c axis by intermolecular N—H...O hydrogen bonds. [ABSTRACT FROM AUTHOR]

In the crystal structure of the title compound, C16H15N3OS, inter­molecular N—H⋯S hydrogen bonds link the mol­ecules together as characteristic dimers, which are further stabilized by weak inter­molecular benzene-ring π–π inter­actions along the a-axis direction. [ABSTRACT FROM AUTHOR]

Solvothermal treatment of metal sulfate and oxalic acid in DMF solution generated three isostructural 3D homonchiral (10,3)-a metal oxalates {(Me2NH2)3(SO4)}2[MII2(ox)3] (M = Fe in 1, Co in 2, Ni in 3) in which D3-symmetric supramolecular cation {(Me2NH2)6SO4}4+formed via electrostatic attractions and 24 N−H···O hydrogen bonds functions as template. The overall structure of 1−3can be described as interpenetration of coordinate [MII2(ox)3]2−and supramolecular {(Me2NH2)3(SO4)}+(10,3)-a nets. Thermal analyses reveal that compounds 1−3show two-stepped decomposition via metal sulfate intermediates. The magnetic behavior of 1and 2exhibits antiferromagnetic coupling between M(II) ions, and magnetic ordering is observed in 2. [ABSTRACT FROM AUTHOR]

In the crystal structure of the title compound, C25H24N4O2S, inter­molecular N—H⋯N and C—H⋯N hydrogen bonds and C—H⋯π inter­actions link the mol­ecules into a two-dimensional network parallel to the bc plane. [ABSTRACT FROM AUTHOR]

Cellulose is the most ancient and abundant polysaccharide on earth. However, the strong hydrogen bond networks and the high crystallinity strongly prevent cellulose from reacting with other compounds to produce higher performance materials. In this work, the investigation via molecular dynamics simulation showed that supercritical 1,1,1,2-tetrafluoroethane (SC R134a) could effectively destroy the strong hydrogen bond networks of cellulose and activate cellulose. Furthermore, experiments were also conducted to support the simulation results, where cellulose was activated via introducing SC R134a and subsequently used in the synthesis of cellulose acetate. The experimental results revealed that SC R134a exhibited a prominent effect on activating cellulose. The crystallinity of cellulose decreased from 0.926 to 0.686 after being activated by SC R134a. In addition the morphology (SEM) of cellulose suggested that the average diameter increased by 25% and numerous cracks appeared on the outer surface of cellulose fibers. Moreover, the consumption of reagents for synthesizing cellulose acetate decreased sharply, especially for acetic acid, which was only 25% of that used in industry, therefore, making the process much more green and energy-saving. [ABSTRACT FROM AUTHOR]

In the crystal structure of the title compound, C14H11FN2OS, the mol­ecules form centrosymmetric hydrogen-bonded dimers, with the S atom forming an inter­molecular hydrogen bond with the H atom of an NH group. [ABSTRACT FROM AUTHOR]

In the title compound, C16H15N3OS, mol­ecules form inversion-related dimers via N—H⋯S hydrogen bonds. The structure is further stabilized by inter­molecular π–π stacking inter­actions down the a axis. [ABSTRACT FROM AUTHOR]

The asymmetric unit of the title compound, [Co(H2O)6](C8H6NO5)2·5H2O, contains one [Co(H2O)6]2+ cation, two C8H6NO5− anions and five uncoordinated water mol­ecules. Cations and anions are linked through O—H⋯O hydrogen bonding involving the uncoordinated water mol­ecules, resulting in a three-dimensional network. [ABSTRACT FROM AUTHOR]