Dependence of the number of hydrogen bonds per water molecule on its distance to a hydrophobic surface and a thereupon-based model for hydrophobic attraction

2010 ◽  
Vol 133 (19) ◽  
pp. 194105 ◽  
Author(s):  
Y. S. Djikaev ◽  
Eli Ruckenstein
2007 ◽  
Vol 72 (8) ◽  
pp. 1122-1138 ◽  
Author(s):  
Milan Uhlár ◽  
Ivan Černušák

The complex NO+·H2S, which is assumed to be an intermediate in acid rain formation, exhibits thermodynamic stability of ∆Hº300 = -76 kJ mol-1, or ∆Gº300 = -47 kJ mol-1. Its further transformation via H-transfer is associated with rather high barriers. One of the conceivable routes to lower the energy of the transition state is the action of additional solvent molecule(s) that can mediate proton transfer. We have studied several NO+·H2S structures with one or two additional water molecule(s) and have found stable structures (local minima), intermediates and saddle points for the three-body NO+·H2S·H2O and four-body NO+·H2S·(H2O)2 clusters. The hydrogen bonds network in the four-body cluster plays a crucial role in its conversion to thionitrous acid.


2012 ◽  
Vol 68 (4) ◽  
pp. o1204-o1204 ◽  
Author(s):  
Sanaz Khorasani ◽  
Manuel A. Fernandes

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.


2007 ◽  
Vol 63 (3) ◽  
pp. m905-m907 ◽  
Author(s):  
Hazel S. Wilkinson ◽  
William T. A. Harrison

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.


2006 ◽  
Vol 62 (5) ◽  
pp. o1754-o1755
Author(s):  
Neng-Fang She ◽  
Sheng-Li Hu ◽  
Hui-Zhen Guo ◽  
An-Xin Wu

The title compound, C24H18Br2N4O2·H2O, forms a supramolecular structure via N—H...O, O—H...O and C—H...O hydrogen bonds. In the crystal structure, the water molecule serves as a bifurcated hydrogen-bond acceptor and as a hydrogen-bond donor.


Author(s):  
Zhe An ◽  
Jing Gao ◽  
William T. A. Harrison

The syntheses and crystal structures of 0.25-aqua(benzene-1,4-dicarboxylato-κ2O,O′)bis(sparfloxacin-κ2O,O′)manganese(II) dihydrate, [Mn(C8H4O4)(C19H22F2N4O3)2(H2O)0.25]·2H2O or [Mn(bdc)(Hspar)2(H2O)0.25]·2H2O, (I), and bis(sparfloxacin-κ2O,O′)copper(II) benzene-1,4-dicarboxylate dihydrate, [Cu(C19H22F2N4O3)2](C8H4O4)·2H2O or [Cu(Hspar)2](bdc)·2H2O, (II), are reported (Hspar = sparfloxacin and bdc = benzene-1,4-dicarboxylate). The Mn2+ion in (I) is coordinated by twoO,O′-bidentate Hspar neutral molecules (which exist as zwitterions) and anO,O′-bidentate bdc dianion to generate a distorted MnO6trigonal prism. A very long bond [2.580 (12) Å] from the Mn2+ion to a 0.25-occupied water molecule projects through a square face of the prism. In (II), the Cu2+ion lies on a crystallographic inversion centre and a CuO4square-planar geometry arises from its coordination by twoO,O′-bidentate Hspar molecules. The bdc dianion acts as a counter-ion to the cationic complex and does not bond to the metal ion. The Hspar ligands in both (I) and (II) feature intramolecular N—H...O hydrogen bonds, which closeS(6) rings. In the crystals of both (I) and (II), the components are linked by N—H...O, O—H...O and C—H...O hydrogen bonds, generating three-dimensional networks.


2014 ◽  
Vol 70 (2) ◽  
pp. m75-m75 ◽  
Author(s):  
Marwa Mghandef ◽  
Habib Boughzala

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.


Author(s):  
Ponnusamy Poornima Devi ◽  
Doraisamyraja Kalaivani

In the anion of the title hydrated molecular salt, C4H8N3O+·C12H9N4O7−·H2O [systematic name: 2-amino-1-methyl-4-oxo-4,5-dihydro-1H-imidazol-3-ium 5-(2,4-dinitrophenyl)-1,3-dimethyl-2,6-dioxo-1,2,3,6-tetrahydropyrimidin-4-olate monohydrate], the 2,4-dinitrophenyl ring is inclined to the mean plane of the pyrimidine ring [r.m.s. deviation = 0.37 Å] by 43.24 (8)°. The five-membered ring of the creatininium cation (2-amino-1-methyl-4-oxo-4,5-dihydro-1H-imidazol-3-ium) is essentially planar with an r.m.s. deviation of 0.015 Å. In the crystal, the anions and cations are linkedviaN—H...O hydrogen bonds, forming sheets parallel to theabplane. The sheets are linkedviaO—H...O hydrogen bonds involving the water molecule, forming a three-dimensional framework. Within the framework, there are C—H...O hydrogen bonds present. The title molecular salt displays anticonvulsant and hypnotic activities.


2006 ◽  
Vol 62 (7) ◽  
pp. m1719-m1721 ◽  
Author(s):  
Luiz Everson da Silva ◽  
Antonio Carlos Joussef ◽  
Sabine Foro ◽  
Boris Schmidt

In the title compound, [Zn(C15H10FN2O2 S)2]·0.5H2O, the Zn atom has a distorted tetrahedral geometry, formed by the N atoms of the quinoline and the sulfonamide groups. The water molecule occupies a special position on a twofold axis. Intermolecular C—H...O hydrogen bonds to the sulfonyl O atoms link the molecules into a three-dimensional network.


2012 ◽  
Vol 68 (4) ◽  
pp. m379-m379 ◽  
Author(s):  
Qiong Liu

In the title compound, [K2(C8H6N3O2)2(H2O)]n, each K+ion is seven-coordinated by one O atom from a bridging water molecule, five carboxylate O atoms and one N atom from a benzotriazole group, forming a distorted mono-capped octahedral geometry. In the crystal, the carboxylate groups act as bridging ligands, forming a two-dimensional polymer parallel to (001). The aqua ligand, which lies on a twofold rotation axis, forms intermolecular O—H...O hydrogen bonds within these layers.


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