Dependence of the frequencies of intermolecular vibrations of associated water molecules upon the size of the association complexes

1970 ◽  
Vol 23 (8) ◽  
pp. 1507 ◽  
Author(s):  
AA Vetrov ◽  
BP Shelyukhaev

The intermolecular vibration frequencies for associated water molecules have been calculated by the Elyashevich-Wilson technique. Slight variations of the geometric parameters of the water molecules and hydrogen bridges leave the intermolecular vibration frequencies almost unaffected. The values of these frequencies depend solely upon the force constants of the hydrogen bonds and the angles adjacent to a hydrogen bond. The spectra of associations containing two, three, four, and five water molecules are found to be sufficiently distinct from each other for their differences to be detected by experiment.


Author(s):  
Graham Smith ◽  
Urs D. Wermuth

In the structure of the brucinium salt of 4-aminophenylarsonic acid (p-arsanilic acid), systematically 2,3-dimethoxy-10-oxostrychnidinium 4-aminophenylarsonate tetrahydrate, (C23H27N2O4)[As(C6H7N)O2(OH)]·4H2O, the brucinium cations form the characteristic undulating and overlapping head-to-tail layered brucine substructures packed along [010]. The arsanilate anions and the water molecules of solvation are accommodated between the layers and are linked to them through a primary cation N—H...O(anion) hydrogen bond, as well as through water O—H...O hydrogen bonds to brucinium and arsanilate ions as well as bridging water O-atom acceptors, giving an overall three-dimensional network structure.



IUCrData ◽  
2018 ◽  
Vol 3 (8) ◽  
Author(s):  
Błażej Dziuk ◽  
Anna Jezuita

The asymmetric unit of the title compound, C10H9N2 +·0.5C2O4 2−·C2H2O4·H2O, consists of a 2,2′-bipyridinium cation, half an oxalate dianion, one oxalic acid and one water molecule. One N atom in 2,2′-bipyridine is unprotonated, while the second is protonated and forms an N—H...O hydrogen bond. In the crystal, the anions are connected with surrounding acid molecules and water molecules by strong near-linear O—H...O hydrogen bonds. The water molecules are located between the anions and oxalic acids; their O atoms participate as donors and acceptors, respectively, in O—H...O hydrogen bonds, which form sheets arranged parallel to the ac plane.



2014 ◽  
Vol 70 (5) ◽  
pp. o549-o549
Author(s):  
Yohsuke Nikawa ◽  
Kyoko Fujita ◽  
Keiichi Noguchi ◽  
Hiroyuki Ohno

In the crystal structure of the title compound, C5H14NO4P·H2O, the zwitterionic phosphocholine molecules are connected by an O—H...O hydrogen bond between the phosphate groups, forming a zigzag chain along theb-axis direction. The chains are further connected through O—H...O hydrogen bonds involving water molecules, forming a layer parallel to (101). Three and one C—H...O interactions are also observed in the layer and between the layers, respectively. The conformation of the N—C—C—O backbone isgauchewith a torsion angle of −75.8 (2)°



2012 ◽  
Vol 68 (5) ◽  
pp. o209-o212 ◽  
Author(s):  
Barbara Wicher ◽  
Krystian Pyta ◽  
Piotr Przybylski ◽  
Ewa Tykarska ◽  
Maria Gdaniec

Rifampicin belongs to the family of naphthalenic ansamycin antibiotics. The first crystal structure of rifampicin in the form of the pentahydrate was reported in 1975 [Gadret, Goursolle, Leger & Colleter (1975).Acta Cryst.B31, 1454–1462] with the rifampicin molecule assumed to be neutral. Redetermination of this crystal structure now shows that one of the phenol –OH groups is deprotonated, with the proton transferred to a piperazine N atom, confirming earlier spectroscopic results that indicated a zwitterionic form for the molecule, namely (2S,12Z,14E,16S,17S,18R,19R,20R,21S,22R,23S,24E)-21-acetyloxy-6,9,17,19-tetrahydroxy-23-methoxy-2,4,12,16,18,20,22-heptamethyl-8-[(E)-N-(4-methylpiperazin-4-ium-1-yl)formimidoyl]-1,11-dioxo-1,2-dihydro-2,7-(epoxypentadeca[1,11,13]trienimino)naphtho[2,1-b]furan-5-olate pentahydrate, C43H58N4O12·5H2O. The molecular structure of this antibiotic is stabilized by a system of four intramolecular O—H...O and N—H...N hydrogen bonds. Four of the symmetry-independent water molecules are arrangedviahydrogen bonds into helical chains extending along [100], whereas the fifth water molecule forms only one hydrogen bond, to the amide group O atom. The rifampicin molecules interactviaO—H...O hydrogen bonds, generating chains along [001]. Rifampicin pentahydrate is isostructural with recently reported rifampicin trihydrate methanol disolvate.



2014 ◽  
Vol 70 (7) ◽  
pp. o784-o784 ◽  
Author(s):  
Yoshinobu Ishikawa ◽  
Kohzoh Watanabe

In the title hydrate, C19H16N2O4·H2O, the 4H-chromen-4-one segment is slightly twisted, with a dihedral angle between the two six-membered rings of 3.30 (5)°. The dihedral angles between the plane of the pyranone ring and the hydrazide plane and between the planes of the pyranone ring and the benzene ring of thep-methoxybenzene unit are 26.69 (4) and 2.23 (3)°, respectively. The molecule is connected to the solvent water molecule by an N—H...O hydrogen bond. In the crystal, there are π–π stacking interactions between centrosymmetrically related pyranone rings [centroid–centroid distance = 3.5394 (9) Å], as well as bridges formed by the water moleculesviaO—H...O hydrogen bonds.



Author(s):  
L. Vella-Zarb ◽  
U. Baisch

The crystal structure of the hexahydrate co-crystal of gallic acid and caffeine, C7H6O5·3C8H10N4O2·6H2O or GAL3CAF·6H2O, is a remarkable example of the importance of hydrate water acting as structural glue to facilitate the crystallization of two components of different stoichiometries and thus to compensate an imbalance of hydrogen-bond donors and acceptors. The water molecules provide the additional hydrogen bonds required to form a crystalline solid. Whereas the majority of hydrogen bonds forming the intermolecular network between gallic acid and caffeine are formed by crystal water, only one direct classical hydrogen bond between two molecules is formed between the carboxylic oxygen of gallic acid and the carbonyl oxygen of caffeine with d(D...A) = 2.672 (2) Å. All other hydrogen bonds either involve crystal water or utilize protonated carbon atoms as donors.



2014 ◽  
Vol 70 (2) ◽  
pp. o169-o170
Author(s):  
Alex Fabiani Claro Flores ◽  
Juliano Rosa de Menezes Vicenti ◽  
Lucas Pizzuti ◽  
Patrick Teixeira Campos

In the title compound, C17H18Cl3NO5·H2O, intramolecular N—H...O and C—H...Cl hydrogen bonds formS(6) andS(5) ring motifs, respectively. The chiral organic molecule is connected to the solvent water molecule by a short O—H...O hydrogen bond. In the crystal, a weak C—H...Cl interaction connects the organic molecules along [100] while the water molecules act as bridges between the organic molecules in both the [100] and [010] directions, generating layers parallel to theabplane.



2018 ◽  
Vol 33 (4) ◽  
pp. 319-326
Author(s):  
Austin M. Wheatley ◽  
James A. Kaduk ◽  
Amy M. Gindhart ◽  
Thomas N. Blanton

The crystal structure of vardenafil hydrochloride trihydrate has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional techniques. Vardenafil hydrochloride trihydrate crystallizes in space group C2/c (#15) with a = 34.78347(16), b = 11.56752(4), c = 14.69308(5) Å, β = 93.3410(4), V = 5901.839(30) Å3, and Z = 8. The fused ring system and the phenyl ring are nearly co-planar; the interplanar angle between them is 6.0°. Two intramolecular hydrogen bonds help determine this conformation. These planes stack along the c-axis. The side chains of these ring systems have a large Uiso and are neighbors in the stacks. Along the a-axis, these stacks are separated by hydrophilic layers of chloride, water molecules, and the positively charged nitrogen atoms of the vardenafil cation. Hydrogen bonds are prominent in the crystal structure. The protonated nitrogen atom forms a strong hydrogen bond to the chloride anion. The water molecules form a hexagon, making hydrogen bonds with themselves, as well as the C1 and a ring nitrogen atom. These discrete hydrogen bonds form a cluster, and there is no extended hydrogen bond network. There are many C–H⋯Cl, C–H⋯O, and C–H⋯N hydrogen bonds, which (although individually weak) contribute significantly to the crystal energy. The powder pattern is included in the Powder Diffraction File™ as entry 00-066-1620.



2012 ◽  
Vol 68 (6) ◽  
pp. o1623-o1623
Author(s):  
Juanzhi Yan ◽  
Ling Ma ◽  
Miaoli Zhu ◽  
Xiangdong Zhang ◽  
Chunhua Ge

In the title compound, C14H16N2O8·2H2O, the complete organic molecule is generated by crystallographic inversion symmetry. The dihedral angles between the aniline ring and the acetic acid groups are almost identical, viz. 82.61 (7) and 80.33 (7)°. In the crystal, O—H...O hydrogen bonds link the organic molecules and water molecules, forming zigzag chains the c axis. An intramolecular O—H...O hydrogen bond is also observed.



2015 ◽  
Vol 71 (5) ◽  
pp. o349-o350
Author(s):  
Joel T. Mague ◽  
Shaaban K. Mohamed ◽  
Mehmet Akkurt ◽  
Antar A. Abdelhamid ◽  
Mustafa R. Albayati

In the title hydrate, C16H23BrN2O·2H2O, the organic molecule features a strong intramolecular O—H...N hydrogen bond. The piperidine ring, in addition, adopts a chair conformation with the exocyclic C—N bond in an equatorial orientation. The water molecules of crystallization are disordered (each over two sets of sites with half occupancy. In the crystal, they associate into corrugated (100) sheets of (H2O)4tetramers linked by O—H...O hydrogen bonds. The organic molecules, in turn, are arranged at both sides of these sheets, linked by water–piperidine O—H...N hydrogen bonds.



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