Observation of librational modes of water molecules in single crystal hydrates by neutron scattering

Small-angle neutron scattering is used to measure the number of bound water molecules associating with three polymers over a wide concentration range. Different fitting workflows are evaluated and recommended depending on the concentration regime.

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Konkurrierende Liganden: Theophyllin als nicht- und stark koordinierender Ligand in Quecksilber(II)-Komplexen / Competing Ligands: Theophylline as Non- and Strongly Coordinating Ligand in Mercury(II) Complexes

Zeitschrift für Naturforschung B ◽

10.1515/znb-2006-0617 ◽

2006 ◽

Vol 61 (6) ◽

pp. 758-765 ◽

Cited By ~ 4

Author(s):

Matthias Nolte ◽

Ingo Pantenburg ◽

Gerd Meyer

Keyword(s):

Oxygen Atom ◽

Water Molecule ◽

Aqueous Solutions ◽

Single Crystal ◽

Coordination Polymers ◽

Water Molecules ◽

Slow Evaporation ◽

Monoclinic Symmetry ◽

X Ray ◽

Chloride Ligand

[{Hg(CF3)2}(ThpH)(H2O)](H2O) (1), [{Hg4(Thp)4}(ClO4)4(H2O)8](H2O)4 (2), [{Hg(ThpH)2} (NO3)](NO3) (3) and {Hg(Thp)Cl}(H2O) (4) (ThpH = theophylline, C7H8N4O2) have been synthesized by slow evaporation of aqueous solutions of the mercuric salts Hg(CF3)2, Hg(ClO4)2, Hg(NO3)2, or HgCl2 and theophylline. Their crystal structures were determined on the basis of single crystal X-ray data. The coordination polymers 1 and 2 crystallize with triclinic symmetry, P1̅ (no. 2), with a = 468.8(2), b = 1256.4(5), c = 1445.5(6) pm, α = 67.15(3), β = 89.21(3), γ = 89.40(3)° and a = 833.6(1), b = 1862.7(2), c = 2182.9(2) pm, α = 111.61(1), β = 90.98(1), γ = 95.51(1)°, respectively. 3 and 4 crystallize with monoclinic symmetry, Pc (no. 7), a =1194.1(1), b=1258.8(2), c=735.5(2) pm, β =96.96(2)° and P21/n (no. 14), a=1069.0(2), b =911.6(1), c=1089.9(2) pm and β = 96.87(2)°. In 1 the theophylline molecules are non-coordinating to mercury and leave the Hg(CF3)2 molecule unchanged. Only weak electrostatic attractions to one keto-oxygen atom of theophylline and one water molecule hold this co-crystallisate together. In 2, the theophyllinate anion, Thp−, strongly coordinates with both N(7) and N(9) to HgII forming a large ring with eight Hg atoms that incorporates the water molecules. One sort of nitrate ions in 3 is weakly attached to HgII with the theophylline molecules still bound strongly through N(9). The chloride ligand and the theophyllinate ion seem to have the same strengths as ligands in 4 as they are both attached to HgII with the shortest distances possible

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Motions of Water Molecules in Potassium Ferrocyanide Trihydrate, Water, and Ice: A Neutron Scattering Study

The Journal of Chemical Physics ◽

10.1063/1.1727754 ◽

1966 ◽

Vol 45 (4) ◽

pp. 1312-1317 ◽

Cited By ~ 26

Author(s):

J. J. Rush ◽

P. S. Leung ◽

T. I. Taylor

Keyword(s):

Neutron Scattering ◽

Potassium Ferrocyanide ◽

Water Molecules ◽

Scattering Study ◽

Neutron Scattering Study ◽

Potassium Ferrocyanide Trihydrate

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Low-frequency single-crystal Raman, far-infrared, and inelastic neutron scattering studies of acetanilide at low temperature

The Journal of Physical Chemistry ◽

10.1021/j100166a067 ◽

1991 ◽

Vol 95 (13) ◽

pp. 5281-5286 ◽

Cited By ~ 6

Author(s):

Clifford T. Johnston ◽

Stephen F. Agnew ◽

Juergen Eckert ◽

Llewellyn H. Jones ◽

Basil I. Swanson ◽

...

Keyword(s):

Low Temperature ◽

Neutron Scattering ◽

Single Crystal ◽

Inelastic Neutron Scattering ◽

Low Frequency ◽

Far Infrared ◽

Inelastic Neutron

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Synthesis, Single Crystal Structural Investigation, Hirshfeld Surface Analysis, Thermoanalysis and Spectroscopic Study of Two New Cu(II) and Co(II) Transition-Metal Complexes

Crystals ◽

10.3390/cryst11080986 ◽

2021 ◽

Vol 11 (8) ◽

pp. 986

Author(s):

Rim Boubakri ◽

Mirosław Szybowicz ◽

Mariola Sadej ◽

Sarra Soudani ◽

Frédéric Lefebvre ◽

...

Keyword(s):

Hydrogen Bonds ◽

Single Crystal ◽

Organic Ligand ◽

Free Water ◽

Pyrimidine Ring ◽

Water Molecules ◽

Absorption Bands ◽

Infrared And Raman Spectroscopy ◽

Homo And Lumo ◽

Coordinated Water

Two new complexes, [Cu(dimpyr)2(H2O)2](NO3)2.2H2O (1) and (Hamdimpy)2[CoCl4].H2O (2), with the monodentate ligand 2-amino-6-methylpyrimidin-4-(1H)-one (dimpyr) and the countercation 4-amino-2,6-dimetylpyrimidium (Hamdimpy), respectively, were prepared and characterized by single crystal X-ray diffraction, elemental analysis and IR spectroscopy. In (1), the Cu(II) cation is tetracoordinated, in a square plan fashion, by two nitrogen atoms from the pyrimidine ring of the organic ligand and two oxygen atoms of two coordinated water molecules. In the atomic arrangement, the CuO2N2 square planes are interconnected via the formation of O-H…O hydrogen bonds involving both coordinated and free water molecules and NO3− nitrate anions to form inorganic layers parallel to the (a, b) plane at z = (2n + 1)/4. In (2), the central atom Co(II) is four-coordinated in a distorted tetrahedral fashion by four Cl− ions. The [CoCl4]2− tetrahedra are arranged parallel to the plane (110) at x = (2n + 1)/2 and the organic cations are grafted between them by establishing with them hydrogen bonds of CH…Cl and NH…Cl types. The vibrational absorption bands were identified by infrared and Raman spectroscopy. Intermolecular interactions were investigated via Hirshfeld surfaces and electronic properties such as HOMO and LUMO energies were derived. The two compounds were characterized by thermal analysis to determine their thermal behavior with respect to temperature.

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Water modulates the lamellar structure and interlayer correlation of poly(perfluorooctyl acrylate) films: a specular and off-specular neutron scattering study

Polymer Journal ◽

10.1038/s41428-021-00555-2 ◽

2021 ◽

Author(s):

Akihisa Yamamoto ◽

Yuji Higaki ◽

Judith Thoma ◽

Esther Kimmle ◽

Ryohei Ishige ◽

...

Keyword(s):

Neutron Scattering ◽

Osmotic Pressure ◽

Correlation Length ◽

Ethyl Acrylate ◽

Contact Angles ◽

Water Repellent ◽

Water Molecules ◽

Coating Materials ◽

Water Contact ◽

Vertical Correlation

AbstractComb-like polymers with pendant-like perfluorocarbon side chains self-assemble into smectic lamellae and have been extensively used as water-repellent, hydrophobic coating materials characterized by large water contact angles (θ > 120°). As poly(perfluorooctyl acrylate) films are “apparently hydrophobic” (θ > 120°), the interaction of such materials and water molecules has been largely overlooked. To unravel the molecular-level interactions between water and apparently hydrophobic polymers, specular and off-specular neutron scattering experiments were conducted at defined osmotic pressure ΠH2O. The poly{2-[(perfluorooctylethyl)carbamate]ethyl} acrylate (PFAUr-C8), which had a carbamate linker, transitioned to another lamellar phase at 89 °C. At T = 25 °C; the lamellar periodicity of PFAUr-C8 slightly increased with decreasing osmotic pressure, while the vertical correlation length increased. However, the poly[(perfluorooctyl)ethyl] acrylate (PFA-C8) that did not contain a carbamate linker directly transitioned to a disordered phase at 84 °C. The lamellar periodicity of PFA-C8 was largely independent of the osmotic pressure, suggesting that PFA-C8 was poorly hydrated. Remarkably, the vertical correlation length decreased with decreasing osmotic pressure. Because hydration facilitated by the linker modulated the smectic lamellae of the poly(perfluoroalkyl acrylate), water molecules could be used to optimize the self-assembly of apparently hydrophobic liquid crystalline polymers.

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Phase transformations in cucurbituril host-guest complexes

Acta Crystallographica Section A Foundations and Advances ◽

10.1107/s205327331409353x ◽

2014 ◽

Vol 70 (a1) ◽

pp. C646-C646

Author(s):

Oksana Danylyuk ◽

Karolina Kedra-Krolik ◽

Marta Worzakowska ◽

Joanna Osypiuk-Tomasik ◽

Vladimir Fedin

Keyword(s):

Single Crystal ◽

Crystal Lattice ◽

Supramolecular Assembly ◽

Water Molecules ◽

Guest Molecules ◽

X Ray ◽

Host Guest Complex ◽

Crystallographic Study ◽

Partial Dehydration ◽

Structure Changes

The retention of crystallinity upon desolvation of molecular crystals is not common, as the molecules are rigidly and densely packed in the crystals and the original framework usually collapses once solvent is removed from the structure. However, in rare cases the host framework remains substantially unaffected by solvent (guest) removal yielding structure with open channels or discrete lattice voids that can show permanent porosity. [1] Furthermore, sometimes happens, the desolvation process proceeds as single-crystal to single-crystal transformation resulting in distortion and sliding of the structure, changes in conformation, coordination modes and/or space group. Here we would like to present crystallographic study and thermal analysis on the dehydration process of the crystalline supramolecular complex between macrocyclic host cucurbit[6]uril and dopamine. In the solid state the 1:1 host-guest complex assembles into hexameric tubes with water-filled interior channels. Another set of water channels is created between three neighboring tubes in the crystal lattice. The crystals of such supramolecular assembly are not stable when out from mother solution and immediately start to loose water upon exposure to air. However, despite severe cracking the crystals dried in air maintained their integrity and still gave satisfactory diffraction pattern. The X-ray analysis showed significant decrease in the unit cell volume of the partially dehydrated crystals that corresponds to the liberation of some of the water molecules from the channels. Moreover, the reorganization of dopamine guest molecules has occurred in the crystal lattice as a response to the escape of water molecules from the structure. The partial dehydration and reorganization of the supramolecular framework proceeds via a single-crystal to single-crystal mechanism.

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Crystal Structure of Calcium Picrate Pentahydrate: A New Eight-Coordinate Stereochemistry for [M(bidentate)2(unidentate)4]

Australian Journal of Chemistry ◽

10.1071/ch9790301 ◽

1979 ◽

Vol 32 (2) ◽

pp. 301 ◽

Cited By ~ 4

Author(s):

V Diakiw ◽

TW Hambley ◽

DL Kepert ◽

CL Raston ◽

AH White

Keyword(s):

Crystal Structure ◽

Water Molecule ◽

Single Crystal ◽

Title Compound ◽

Lattice Site ◽

The Other ◽

Water Molecules ◽

X Ray Diffraction ◽

Triangular Face ◽

X Ray

The crystal structure of the title compound, Ca(C6H2N307)2,5H2O, has been determined by single-crystal X-ray diffraction at 295(1) K and refined by least squares to a residual of 0.049 for 1513 'observed' reflections. Crystals are orthorhombic, Pmab, a 24.169(6), b l0.292(7), c 8.554(2) �, Z 4. The stereochemistry about the calcium has not been observed previously for the system [M(bidentate)2- (unidentate)4]; in the present structure, the calcium is coordinated by a pair of bidentate picrate ligands and the four water molecules in an array in which three of the water molecules occupy a triangular face of a square antiprism, the overall array having m symmetry. The remaining water molecule occupies a lattice site with no close interaction with the other species.

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Crystal structure of coalingite

Mineralogical Magazine ◽

10.1180/minmag.1971.038.295.02 ◽

1971 ◽

Vol 38 (295) ◽

pp. 286-294 ◽

Cited By ~ 27

Author(s):

J. Pastor-Rodriguez ◽

H. F. W. Taylor

Keyword(s):

Crystal Structure ◽

Single Crystal ◽

Water Molecules ◽

Structural Elements ◽

Structural Element ◽

X Ray ◽

Octahedral Sites ◽

Carbonate Ions ◽

Disordered Layer ◽

Ray Methods

SummaryThe crystal structure of coalingite (Mg10Fe2(OH)24(CO3)·2H2O) has been determined using single-crystal X-ray methods. The mineral is trigonal, with space group Rm, aH = 3·12, cH = 37·4 Å, Z = ½, and (0001) cleavage. The structure is of a layer type, and is based on a structural element about 12·5 Å thick in the c-direction and consisting of two brucite-like layers and one disordered layer containing carbonate ions and water molecules and resembling those in sjögrenite and pyroaurite. The unit cell comprises three of these structural elements stacked together in the c-direction. The Mg2+ and Fe3+ ions are randomly distributed among all the octahedral sites of the brucite-like layers. The structure closely resembles those of sjögrenite and pyroaurite, but has two brucite-like layers between each CO32−−H2O layer where these have one. There is a tendency to random interstratification, and the crystals appear to contain intergrown regions of brucite and of sjögrenite or pyroaurite. Coalingite-K probably has a similar structure, but with three brucite-like layers between each -H2O layer; its idealized formula is probably Mg16Fe2(OH)36(CO3).2H2O.

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