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Water Chain (water + chain)
Selected AbstractsUnusual T4(1) Water Chain Stabilized in the One-Dimensional Chains of a Copper(II) Coordination PolymerEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 13 2007Yi Jin Abstract A novel T4(1) water chain in a new CuII coordination polymer, {[Cu(C4H6N2)2(C4H2O4)] (H2O)3}n (1, where C4H6N2 = 2-methylimidazole, C4H2O4 = maleate), has been synthesized and structurally characterized by single-crystal X-ray diffraction. Thermogravimetry, infrared spectroscopy, elemental analysis, and magnetic analysis have also been used to characterize 1. Complex 1 crystallizes in the trigonal space group P3221, and the 1-D chains composed of cyclic water tetramers play an important role in stabilizing the overall polymeric structure. Furthermore, this 1-D water chain presents an unusual association mode of water molecules.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Water Chains in Hydrophobic Crystal Channels: Nanoporous Materials as Supramolecular Analogues of Carbon Nanotubes,ANGEWANDTE CHEMIE, Issue 30 2010Ramalingam Natarajan Dr. Porendesign: Nanoporöse Steroidkristalle können mit einer Vielzahl an Kanaleigenschaften maßgeschneidert hergestellt werden. So lassen sich die Wände mit aromatischen Gruppen auskleiden, um das Innere von Kohlenstoffnanoröhren (CNTs) nachzuahmen. Die Poren in diesen Strukturen sind von ,Wasserdrähten" besetzt, wie für Wasser in CNTs selbst vorgeschlagen wurde. [source] ChemInform Abstract: Structure and Stability of Water Chains (H2O)n, n = 5,20CHEMINFORM, Issue 29 2009R. Parthasarathi Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Unusual T4(1) Water Chain Stabilized in the One-Dimensional Chains of a Copper(II) Coordination PolymerEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 13 2007Yi Jin Abstract A novel T4(1) water chain in a new CuII coordination polymer, {[Cu(C4H6N2)2(C4H2O4)] (H2O)3}n (1, where C4H6N2 = 2-methylimidazole, C4H2O4 = maleate), has been synthesized and structurally characterized by single-crystal X-ray diffraction. Thermogravimetry, infrared spectroscopy, elemental analysis, and magnetic analysis have also been used to characterize 1. Complex 1 crystallizes in the trigonal space group P3221, and the 1-D chains composed of cyclic water tetramers play an important role in stabilizing the overall polymeric structure. Furthermore, this 1-D water chain presents an unusual association mode of water molecules.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] ZnO Nanoparticles From a Metal-Organic Framework Containing ZnII MetallacyclesEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 4 2007Harjyoti Thakuria Abstract Nitrilotriacetic acid (H3NTA) reacts in the solid phase with zinc hydroxide (1:1) to form a 3D ladder-like metal-organic framework that forms wurtzite ZnO nanoparticles when heated above 600 °C. Complex 1 contains a 1D zig-zag water chain. A mixed coordination network 2 is formed with excess ZnII hydroxide, which, on decomposition at about 500 °C, forms microwires of ZnO.(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007) [source] Crystal structures of isomaltase from Saccharomyces cerevisiae and in complex with its competitive inhibitor maltoseFEBS JOURNAL, Issue 20 2010Keizo Yamamoto The structures of isomaltase from Saccharomyces cerevisiae and in complex with maltose were determined at resolutions of 1.30 and 1.60 Å, respectively. Isomaltase contains three domains, namely, A, B, and C. Domain A consists of the (,/,)8 -barrel common to glycoside hydrolase family 13. However, the folding of domain C is rarely seen in other glycoside hydrolase family 13 enzymes. An electron density corresponding to a nonreducing end glucose residue was observed in the active site of isomaltase in complex with maltose; however, only incomplete density was observed for the reducing end. The active site pocket contains two water chains. One water chain is a water path from the bottom of the pocket to the surface of the protein, and may act as a water drain during substrate binding. The other water chain, which consists of six water molecules, is located near the catalytic residues Glu277 and Asp352. These water molecules may act as a reservoir that provides water for subsequent hydrolytic events. The best substrate for oligo-1,6-glucosidase is isomaltotriose; other, longer-chain, oligosaccharides are also good substrates. However, isomaltase shows the highest activity towards isomaltose and very little activity towards longer oligosaccharides. This is because the entrance to the active site pocket of isomaltose is severely narrowed by Tyr158, His280, and loop 310,315, and because the isomaltase pocket is shallower than that of other oligo-1,6-glucosidases. These features of the isomaltase active site pocket prevent isomalto-oligosaccharides from binding to the active site effectively. [source] Periodicity in proton conduction along a H-bonded chain.INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 3 2008Application to biomolecules Abstract Molecular complexes are constructed to simulate proton transfer channels of the influenza A virus and of the active site of carbonic anhydrase. These complexes consist of proton donor and acceptor groups connected by a chain of water molecules. Quantum chemical calculations on the methylimidazole(H+)H2OCH3COO, model of the M2 virus channel indicate free translational motion of the water molecule between donor and acceptor, as well as concerted transfer of both H-bond protons. The proton transfer barrier does not depend on the position of the bridged water molecule and varies linearly with the difference of electrostatic potentials between the donor and acceptor. When the water chain is elongated, and with various donor and acceptor models, periodicity appears in the H-bond lengths and the progression of proton transfer in each link. This "wave" is shown to propagate along the chain, as it is driven by the displacement of a single proton. One can thereby estimate the velocity of the proton wave and proton conduction time. Computations are performed to examine the influence of immersing the system within a polarizable medium. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2008 [source] Poly[diaquabis(,3 -hexamethylenetetramine)[,2 -2,2,-(piperazine-1,4-diyl)bis(ethanesulfonato)]disilver(I)]: a three-dimensional pillared-layer framework encapsulating a water chain of (H2O)12 clustersACTA CRYSTALLOGRAPHICA SECTION C, Issue 9 2010Peng Guo The title compound, {[Ag2(C8H16N2O6S2)(C6H12N4)2(H2O)2]·12H2O}n, consists of a two-dimensional AgI,hexamethylenetetramine (6,3) net pillared by the 2,2,-(piperazine-1,4-diyl)bis(ethanesulfonate) ligand, which lies across a centre of inversion. This compound can also be viewed as a (3,4)-connected topology by considering the hexamethylenetetramine ligand and the AgI ion as the three- and four-connected nodes, respectively. There is a one-dimensional channel along the a axis accommodating a water chain assembled by the (H2O)12 clusters. [source] Tris(1,10-phenanthroline-,2N,N,)cadmium(II) bis(perchlorate) 3.5-hydrate: a water chain stabilized by perchlorate anionsACTA CRYSTALLOGRAPHICA SECTION C, Issue 4 2010Yu-Hui Sun The title compound, [Cd(C12H8N2)3](ClO4)2·3.5H2O, contains a cross-shaped one-dimensional channel along the c axis which encapsulates an ordered water chain. This water chain features a centrosymmetric cyclic water hexamer unit with a chair-like conformation. Neighbouring hexamers are linked by bridging water molecules. The host perchlorate anions recognize and stabilize the guest water chain via three kinds of hydrogen-bond patterns, leading to the formation of a complex one-dimensional {[(H2O)7(ClO4)4]4,}n anionic chain. One perchlorate acts as a single hydrogen-bond acceptor dangling on the chain, the second perchlorate on the chain serves as a double hydrogen-bond acceptor for only one water molecule to form an R22(6) ring, where both entities lie on a twofold axis, while the third perchlorate, which also lies on a twofold axis, accepts two hydrogen bonds from two equivalent water molecules and is involved in the construction of an R65(14) ring. [source] A novel three-dimensional framework constructed by 2-[(1H -imidazol-1-yl)methyl]-1H -benzimidazole and infinite chains of hydrogen-bonded water moleculesACTA CRYSTALLOGRAPHICA SECTION C, Issue 3 2009De-Qiang Qi A novel three-dimensional framework of 2-[(1H -imidazol-1-yl)methyl]-1H -benzimidazole dihydrate, C11H10N4·2H2O or L·2H2O, (I), in which L acts as both hydrogen-bond acceptor and donor in the supramolecular construction with water, has been obtained by self-assembly reaction of L with H2O. The two independent water molecules are hydrogen bonded alternately with each other to form a one-dimensional infinite zigzag water chain. These water chains are linked by the benzimidazole molecules into a three-dimensional framework, in which each organic molecule is hydrogen bonded by three water molecules. This study shows that the diversity of hydrogen-bonded patterns plays a crucial role in the formation of the three-dimensional framework. More significantly, as water molecules are important in contributing to the conformation, stability, function and dynamics of biomacromolecules, the infinite chains of hydrogen-bonded water molecules seen in (I) may be a useful model for water in other chemical and biological processes. [source] Novel Metallosupramolecular Networks Constructed from CuII, NiII, and CdII with Mixed Ligands: Crystal Structures, Fluorescence, and MagnetismEUROPEAN JOURNAL OF INORGANIC CHEMISTRY, Issue 6 2006Miao Du Abstract Reactions of mixed ligands succinic acid (H2suc) and bent dipyridines, such as 2,5-bis(3-pyridyl)-1,3,4-oxadiazole (3-bpo) and its 4- N -donor analog (4-bpo), with inorganic CuII, NiII, and CdII salts yield three new metal-organic coordination frameworks {[Cu(suc)(3-bpo)(H2O)2]·(H2O)1.75}n (1), {[Ni(suc)(4-bpo)(H2O)2]·(H2O)5}n (3), and {[Cd2(suc)2(3-bpo)2(H2O)2]·(H2O)6.75}n (4), in which the metal centers are linked by bridging ligands 3-bpo/4-bpo and suc2, along two directions to form 2D infinite networks. The corrugated 2D nets of 1 and 4, obtained under hydrothermal conditions, align in an interdigitated manner with the presence of significant aromatic-stacking interactions to result in similar 3D architectures. The 2D sheets in 3 are extended by interlayer hydrogen bonds to afford a 3D structure. However, when succinic acid is replaced by fumaric acid (H2fum) in the reaction with 3-bpo and CuII salt, a metallacyclophane [Cu(Hfum)2(3-bpo)(H2O)]2·(3-bpo)2·(H2O)6 (2) is generated. The binuclear coordinated motifs are hydrogen-bonded to the lattice water chains to furnish a unique 3D channel-like framework, in which the guest 3-bpo molecules are accommodated. The thermal stabilities of these new materials were investigated by thermogravimetric analysis (TGA) of mass loss. The magnetic coupling in complexes 1,3 is antiferromagnetic and very small, which is as expected considering the long organic bridges between the paramagnetic centers. The solid-state luminescence properties of 4 reveal an intense fluorescence emission at 378 nm. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006) [source] Crystal structures of isomaltase from Saccharomyces cerevisiae and in complex with its competitive inhibitor maltoseFEBS JOURNAL, Issue 20 2010Keizo Yamamoto The structures of isomaltase from Saccharomyces cerevisiae and in complex with maltose were determined at resolutions of 1.30 and 1.60 Å, respectively. Isomaltase contains three domains, namely, A, B, and C. Domain A consists of the (,/,)8 -barrel common to glycoside hydrolase family 13. However, the folding of domain C is rarely seen in other glycoside hydrolase family 13 enzymes. An electron density corresponding to a nonreducing end glucose residue was observed in the active site of isomaltase in complex with maltose; however, only incomplete density was observed for the reducing end. The active site pocket contains two water chains. One water chain is a water path from the bottom of the pocket to the surface of the protein, and may act as a water drain during substrate binding. The other water chain, which consists of six water molecules, is located near the catalytic residues Glu277 and Asp352. These water molecules may act as a reservoir that provides water for subsequent hydrolytic events. The best substrate for oligo-1,6-glucosidase is isomaltotriose; other, longer-chain, oligosaccharides are also good substrates. However, isomaltase shows the highest activity towards isomaltose and very little activity towards longer oligosaccharides. This is because the entrance to the active site pocket of isomaltose is severely narrowed by Tyr158, His280, and loop 310,315, and because the isomaltase pocket is shallower than that of other oligo-1,6-glucosidases. These features of the isomaltase active site pocket prevent isomalto-oligosaccharides from binding to the active site effectively. [source] 1,1,-Fc(4-C6H4CO2Et)2 and its unusual salt derivative with Z, = 5, catena -[Na+]2[1,1,-Fc(4-C6H4CO2,)2]·0.6H2O [1,1,-Fc = (,5 -(C5H4)2Fe]ACTA CRYSTALLOGRAPHICA SECTION B, Issue 2 2010John F. Gallagher The neutral diethyl 4,4,-(ferrocene-1,1,-diyl)dibenzoate, Fe[,5 -(C5H4)(4-C6H4CO2Et)]2 (I), yields (II) (following base hydrolysis) as the unusual complex salt poly[disodium bis[diethyl 4,4,-(ferrocene-1,1,-diyl)dibenzoate] 0.6-hydrate] or [Na+]2[Fe{,5 -(C5H4)-4-C6H4CO}2]·0.6H2O with Z, = 5. Compound (I) crystallizes in the triclinic system, space group , with two molecules having similar geometry in the asymmetric unit (Z, = 2). The salt complex (II) crystallizes in the orthorhombic system, space group Pbca, with the asymmetric unit comprising poly[decasodium pentakis[diethyl 4,4,-(ferrocene-1,1,-diyl)dibenzoate] trihydrate] or [Na+]10[Fe{,5 -(C5H4)-4-C6H4CO}2]5·3H2O. The five independent 1,1,-Fc[(4-C6H4CO2),]2 dianions stack in an offset ladder (stepped) arrangement with the ten benzoates mutually oriented cisoid towards and bonded to a central layer comprising the ten Na+ ions and three water molecules [1,1,-Fc = ,5 -(C5H4)2Fe]. The five dianions differ in the cisoid orientations of their pendant benzoate groups, with four having their ,C6H4, groups mutually oriented at interplanar angles from 0.6,(3) to 3.2,(3)° (as ,..., stacked C6 rings) and interacting principally with Na+ ions. The fifth dianion is distorted and opens up to an unprecedented ,C6H4, interplanar angle of 18.6,(3)° through bending of the two 4-C6H4CO2 groups and with several ionic interactions involving the three water molecules (arranged as one-dimensional zigzag chains in the lattice). Overall packing comprises two-dimensional layers of Na+ cations coordinated mainly by the carboxylate O atoms, and one-dimensional water chains. The non-polar Fc(C6H4)2 groups are arranged perpendicular to the layers and mutually interlock through a series of efficient C,H..., stacking contacts in a herringbone fashion to produce an overall segregation of polar and non-polar entities. [source] A novel three-dimensional framework constructed by 2-[(1H -imidazol-1-yl)methyl]-1H -benzimidazole and infinite chains of hydrogen-bonded water moleculesACTA CRYSTALLOGRAPHICA SECTION C, Issue 3 2009De-Qiang Qi A novel three-dimensional framework of 2-[(1H -imidazol-1-yl)methyl]-1H -benzimidazole dihydrate, C11H10N4·2H2O or L·2H2O, (I), in which L acts as both hydrogen-bond acceptor and donor in the supramolecular construction with water, has been obtained by self-assembly reaction of L with H2O. The two independent water molecules are hydrogen bonded alternately with each other to form a one-dimensional infinite zigzag water chain. These water chains are linked by the benzimidazole molecules into a three-dimensional framework, in which each organic molecule is hydrogen bonded by three water molecules. This study shows that the diversity of hydrogen-bonded patterns plays a crucial role in the formation of the three-dimensional framework. More significantly, as water molecules are important in contributing to the conformation, stability, function and dynamics of biomacromolecules, the infinite chains of hydrogen-bonded water molecules seen in (I) may be a useful model for water in other chemical and biological processes. [source] Tetraaquabis(5-carboxy-2-nitrobenzoato-,O)manganese(II) dihydrate: a metal,water chain complex containing cyclic water tetramersACTA CRYSTALLOGRAPHICA SECTION C, Issue 3 2007Li-Qin Xiong In the title complex, [Mn(C8H4NO6)2(H2O)4]·2H2O, cyclic water tetramers forming one-dimensional metal,water chains have been observed. The water clusters are trapped by the co-operative association of coordination interactions and hydrogen bonds. The MnII ion resides on a center of symmetry and is in an octahedral coordination environment comprising two O atoms from two 5-carboxy-2-nitrobenzoate ligands and four O atoms from water molecules. [source] Diaquabis[2,-(4,5-diazafluoren-9-ylidene)picolinohydrazidato-,2N,O]zinc(II) tetrahydrate: a metal,water chain complex containing cyclic water hexamersACTA CRYSTALLOGRAPHICA SECTION C, Issue 10 2006Chun-Xiang Wang In the title compound, [Zn(C17H10N5O)2(H2O)2]·4H2O, cyclic water hexamers forming one-dimensional metal,water chains are observed. The water clusters are trapped by the co-operative association of coordination interactions and hydrogen bonds. The ZnII ion resides on a centre of symmetry and is in an octahedral coordination environment comprising two O atoms and two N atoms from two 2,-(4,5-diazafluoren-9-ylidene)picolinohydrazidate ligands and two water molecules. [source] | ||||||||||