Hydrogen Bonds and Local Ordering of Water Molecules

N,N-Dimethylglycine, C4H9NO2, and its hemihydrate, C4H9NO2·0.5H2O, are discussed in order to follow the effect of the methylation of the glycine amino group (and thus its ability to form several hydrogen bonds) on crystal structure, in particular on the possibility of the formation of hydrogen-bonded `head-to-tail' chains, which are typical for the crystal structures of amino acids and essential for considering amino acid crystals as mimics of peptide chains. Both compounds crystallize in centrosymmetric space groups (PbcaandC2/c, respectively) and have twoN,N-dimethylglycine zwitterions in the asymmetric unit. In the anhydrous compound, there are no head-to-tail chains but the zwitterions formR44(20) ring motifs, which are not bonded to each other by any hydrogen bonds. In contrast, in the crystal structure ofN,N-dimethylglycinium hemihydrate, the zwitterions are linked to each other by N—H...O hydrogen bonds into infiniteC22(10) head-to-tail chains, while the water molecules outside the chains provide additional hydrogen bonds to the carboxylate groups.

Download Full-text

Effect of permanent magnetic field on scale inhibition property of circulating water

Water Science & Technology ◽

10.2166/wst.2017.357 ◽

2017 ◽

Vol 76 (8) ◽

pp. 1981-1991 ◽

Cited By ~ 1

Author(s):

Lili Jiang ◽

Xiayan Yao ◽

Haitao Yu ◽

Xingang Hou ◽

Zongshu Zou ◽

...

Keyword(s):

Magnetic Field ◽

Hydrogen Bonds ◽

Flow Velocity ◽

Magnetic Field Intensity ◽

Water Molecules ◽

Relative Variation ◽

Initial Concentration ◽

Circulating Water ◽

Scale Inhibition ◽

Inhibition Property

Effect of a permanent magnet field on the scale inhibition property of circulating water was investigated. Orthogonal experiments of L16(45) were performed and analyzed using the range analysis method. The operating parameters included magnetic field intensity, initial concentration of Ca2+ and Mg2+, magnetic treatment time, temperature, and flow velocity. Scale inhibition rate, hardness, relative variation in the proportion of free water molecules, electrical conductivity, and relative variation of molecular energy were chosen as the objectives. In addition, the morphology and the composition of CaCO3 and MgCO3 scale were studied by X-ray diffraction analysis. The optimal conditions were initial concentration of 900 mg/L, magnetic field intensity of 0.5 T, temperature of 303 K, time of 54 h and flow velocity of 0.17 m/s. The nuclear magnetic resonance results demonstrated that the number of hydrogen bonds increased between water molecules and hydrated ions. The magnetic field can promote the increase in the number of hydrogen bonds, which can inhibit the formation of calcium and magnesium carbonate precipitation. Moreover, the ratio of calcite, aragonite and vaterite will be changed at different magnetic field intensities, and the aragonite ratio will reach the peak at the optimum conditions.

Download Full-text

Cyclooctanaminium hydrogen succinate monohydrate

Acta Crystallographica Section E Structure Reports Online ◽

10.1107/s1600536812011208 ◽

2012 ◽

Vol 68 (4) ◽

pp. o1204-o1204 ◽

Cited By ~ 2

Author(s):

Sanaz Khorasani ◽

Manuel A. Fernandes

Keyword(s):

Hydrogen Bonds ◽

Water Molecule ◽

Ammonium Cation ◽

Water Molecules ◽

Hydrated Salt ◽

A Chain ◽

Hydrogen Bonded

In the title hydrated salt, C8H18N+·C4H5O4−·H2O, the cyclooctyl ring of the cation is disordered over two positions in a 0.833 (3):0.167 (3) ratio. The structure contains various O—H.·O and N—H...O interactions, forming a hydrogen-bonded layer of molecules perpendicular to thecaxis. In each layer, the ammonium cation hydrogen bonds to two hydrogen succinate anions and one water molecule. Each hydrogen succinate anion hydrogen bonds to neighbouring anions, forming a chain of molecules along thebaxis. In addition, each hydrogen succinate anion hydrogen bonds to two water molecules and the ammonium cation.

Download Full-text

Piperazinium hydrogenarsenate monohydrate

Acta Crystallographica Section E Structure Reports Online ◽

10.1107/s1600536807007763 ◽

2007 ◽

Vol 63 (3) ◽

pp. m905-m907 ◽

Cited By ~ 2

Author(s):

Hazel S. Wilkinson ◽

William T. A. Harrison

Keyword(s):

Hydrogen Bonds ◽

Water Molecule ◽

Title Compound ◽

Water Molecules ◽

Asymmetric Unit ◽

Compound C

In the title compound, C4H12N2 2+·HAsO4 2−·H2O, the component species interact by way of N—H...O and O—H...O hydrogen bonds, the latter leading to infinite sheets of HAsO4 2− anions and water molecules containing R 6 6(18) loops. The asymmetric unit contains one anion, one water molecule and half each of two centrosymmetric cations.

Download Full-text

Crystal structures of {[Cu(Lpn)2][Fe(CN)5(NO)]·H2O}nand {[Cu(Lpn)2]3[Cr(CN)6]2·5H2O}n[where Lpn = (R)-propane-1,2-diamine]: two heterometallic chiral cyanide-bridged coordination polymers

Acta Crystallographica Section E Crystallographic Communications ◽

10.1107/s2056989015005253 ◽

2015 ◽

Vol 71 (4) ◽

pp. 392-397

Author(s):

Olha Sereda ◽

Helen Stoeckli-Evans

Keyword(s):

Hydrogen Bonds ◽

Coordination Polymers ◽

Three Dimensional ◽

Water Molecules ◽

Two Dimensional ◽

Asymmetric Unit ◽

Compound I ◽

Distorted Octahedral ◽

Coordination Spheres ◽

Compound Ii

The title compounds,catena-poly[[[bis[(R)-propane-1,2-diamine-κ2N,N′]copper(II)]-μ-cyanido-κ2N:C-[tris(cyanido-κC)(nitroso-κN)iron(III)]-μ-cyanido-κ2C:N] monohydrate], {[Cu(Lpn)2][Fe(CN)5(NO)]·H2O}n, (I), and poly[[hexa-μ-cyanido-κ12C:N-hexacyanido-κ6C-hexakis[(R)-propane-1,2-diamine-κ2N,N′]dichromium(III)tricopper(II)] pentahydrate], {[Cu(Lpn)2]3[Cr(CN)6]2·5H2O}n, (II) [where Lpn = (R)-propane-1,2-diamine, C3H10N2], are new chiral cyanide-bridged bimetallic coordination polymers. The asymmetric unit of compound (I) is composed of two independent cation–anion units of {[Cu(Lpn)2][Fe(CN)5)(NO)]} and two water molecules. The FeIIIatoms have distorted octahedral geometries, while the CuIIatoms can be considered to be pentacoordinate. In the crystal, however, the units align to form zigzag cyanide-bridged chains propagating along [101]. Hence, the CuIIatoms have distorted octahedral coordination spheres with extremely long semicoordination Cu—N(cyanido) bridging bonds. The chains are linked by O—H...N and N—H...N hydrogen bonds, forming two-dimensional networks parallel to (010), and the networks are linkedviaN—H...O and N—H...N hydrogen bonds, forming a three-dimensional framework. Compound (II) is a two-dimensional cyanide-bridged coordination polymer. The asymmetric unit is composed of two chiral {[Cu(Lpn)2][Cr(CN)6]}−anions bridged by a chiral [Cu(Lpn)2]2+cation and five water molecules of crystallization. Both the CrIIIatoms and the central CuIIatom have distorted octahedral geometries. The coordination spheres of the outer CuIIatoms of the asymmetric unit can be considered to be pentacoordinate. In the crystal, these units are bridged by long semicoordination Cu—N(cyanide) bridging bonds forming a two-dimensional network, hence these CuIIatoms now have distorted octahedral geometries. The networks, which lie parallel to (10-1), are linkedviaO—H...O, O—H...N, N—H...O and N—H...N hydrogen bonds involving all five non-coordinating water molecules, the cyanide N atoms and the NH2groups of the Lpn ligands, forming a three-dimensional framework.

Download Full-text

Crystal structure of the new hybrid material bis(1,4-diazoniabicyclo[2.2.2]octane) di-μ-chlorido-bis[tetrachloridobismuthate(III)] dihydrate

Acta Crystallographica Section E Crystallographic Communications ◽

10.1107/s2056989015019933 ◽

2015 ◽

Vol 71 (11) ◽

pp. 1384-1387

Author(s):

Marwen Chouri ◽

Habib Boughzala

Keyword(s):

Crystal Structure ◽

Aqueous Solution ◽

Hydrogen Bonds ◽

Room Temperature ◽

Molar Ratio ◽

Water Molecules ◽

Site Symmetry ◽

Two Dimensional ◽

Slow Evaporation ◽

Solution Ph

The title compound bis(1,4-diazoniabicyclo[2.2.2]octane) di-μ-chlorido-bis[tetrachloridobismuthate(III)] dihydrate, (C6H14N2)2[Bi2Cl10]·2H2O, was obtained by slow evaporation at room temperature of a hydrochloric aqueous solution (pH = 1) containing bismuth(III) nitrate and 1,4-diazabicyclo[2.2.2]octane (DABCO) in a 1:2 molar ratio. The structure displays a two-dimensional arrangement parallel to (100) of isolated [Bi2Cl10]4−bioctahedra (site symmetry -1) separated by layers of organic 1,4-diazoniabicyclo[2.2.2]octane dications [(DABCOH2)2+] and water molecules. O—H...Cl, N—H...O and N—H...Cl hydrogen bonds lead to additional cohesion of the structure.

Download Full-text

Hydrate von Li3VO4: Synthese und Strukturchemie / Hydrates of Li3VO4: Synthesis and Structural Chemistry

Zeitschrift für Naturforschung B ◽

10.1515/znb-2007-1002 ◽

2007 ◽

Vol 62 (10) ◽

pp. 1235-1245 ◽

Cited By ~ 5

Author(s):

Simone Schnabel ◽

Caroline Röhr

Keyword(s):

Hydrogen Bonds ◽

Building Blocks ◽

Water Molecules ◽

Space Group ◽

Space Groups ◽

Monoclinic Form ◽

Lithium Sulfide ◽

3D Network ◽

Coordination Spheres ◽

A Chain

Stoichiometric hydrates of Li3VO4, the hexahydrate and two polymorphs of the octahydrate, were prepared by evaporation of alkaline aqueous solutions 1 molar in LiOH and 0.5 molar in the metavanadate LiVO3 at r. t. with or without the addition of Lithium sulfide, i. e. at different pH values. Their crystal structures have been determined and refined using single crystal X-ray data; all lithium and hydrogen atom positions were localised and refined without contraints. All three title compounds crystallise in non-centrosymmetric space groups. The water molecules belong to the tetrahedral coordination spheres of the Li cations, i. e. they are embedded as water of coordination exclusively. The tetrahedral orthovanadate(V) anions VO3−4 and the LiO4 tetrahedra are connected via common O corners to form building units which are further held together by strong, nearly linear hydrogen bonds. The hexahydrate Li3VO4 ・ 6H2O (space group R3, a = 962.9(2), c = 869.2(2) pm, Z = 3, R1 = 0.0260) contains isolated orthovanadate(V) anions VO3−4 surrounded by a 3D network of cornersharing Li(H2O)4 tetrahedra forming rings of three, seven and eight units. The water molecules are ‘isolated’ in the sense that no hydrogen bonds are formed between water molecules. The octahydrate is dimorphous: The triclinic polymorph of Li3VO4 ・ 8H2O (space group P1, a = 592.6(2), b = 651.3(2), c = 730.2(4) pm, α = 89.09(2), β = 89.43(2), γ = 88.968(12)°, Z = 1, R1 = 0.0325) contains two types of chains of tetrahedra: One consists of corner-sharing Li(H2O)4 tetrahedra only, the second one is formed by alternating LiO4 and VO4 tetrahedra, also sharing oxygen corners. Only one water molecule is ‘isolated’, the other seven form a branched fragment of a chain with hydrogen bonds between them. In the monoclinic form of Li3VO4・8H2O (space group Pc, a = 732.6(1), b = 653.7(1), c = 1292.9(3) pm, β = 112.21(1)°, Z = 2, R1 = 0.0289) a fragment of a chain of three LiO4 tetrahedra, two of which share a common edge, and one VO4 tetrahedron represent the formular unit. These building blocks are connected via hydrogen bonds formed by three ‘isolated’ water molecules and a chain fragment of five connected water molecules.

Download Full-text

1-(4-Hydroxyphenyl)piperazine-1,4-diium tetrachloridocobalt(II) monohydrate

Acta Crystallographica Section E Structure Reports Online ◽

10.1107/s1600536814001767 ◽

2014 ◽

Vol 70 (2) ◽

pp. m75-m75 ◽

Cited By ~ 3

Author(s):

Marwa Mghandef ◽

Habib Boughzala

Keyword(s):

Hydrogen Bonds ◽

Water Molecule ◽

Three Dimensional ◽

Organic Cations ◽

Water Molecules ◽

Asymmetric Unit ◽

Hybrid Compound ◽

Organic Hybrid ◽

Compound C ◽

Dimensional Network

The asymmetric unit of the title inorganic–organic hybrid compound, (C10H16N2O)[CoCl4]·H2O, consists of a tetrahedral [CoCl4]2−anion, together with a [C10H18N2O]2+cation and a water molecule. Crystal cohesion is achieved through N—H...Cl, O—H...Cl and N—H...O hydrogen bonds between organic cations, inorganic anions and the water molecules, building up a three-dimensional network.

Download Full-text