scholarly journals Low temperature crystal structure, experimental atomic charges and electrostatic potential of ammonium decavanadate hexahydrate (NH4)V10O28·6H2O

2007 ◽  
Vol 72 (6) ◽  
pp. 545-554 ◽  
Author(s):  
Goran Bogdanovic ◽  
Nada Bosnjakovic-Pavlovic ◽  
Bire Spasojevic-De ◽  
Eddine Ghermanic ◽  
Ubavka Mioc
Keyword(s):  
Crystal Structure ◽  
Low Temperature ◽  
Hydrogen Bonds ◽  
Electrostatic Potential ◽  
Water Molecules ◽  
Atomic Charges ◽  
Atomic Group ◽  
Hydrogen Atoms ◽  
X Ray ◽  
Low Temperature Crystal Structure

The X-ray structure of ammonium decavanadate hexahydrate was redetermined at a low temperature (100 K) in order to locate the hydrogen sites and to study the hydrogen bonds. The hydrogen atoms were assigned to the appropriate atomic group, NH4 + cations, and water molecules, missing to the best of our knowledge in the literature. A kappa refinement was performed to estimate the experimental atomic charges. These charges were used to generale the electrostatic potential on the molecular surfaces of decavanadate polyanions isolated from the influence of the crystal lattice. Comparisons with previous theoretical (ab initio) calculations were made and are also discussed. .

scholarly journals Rerefinement of poly[diaquabis(μ3-2-methylpropanoato-κ4 O:O,O′:O′)bis(μ3-2-methylpropanoato-κ3 O:O:O)(μ2-2-methylpropanoato-κ3 O:O,O′)(2-methylpropanoato-κ2 O,O′)trilead(II)]

IUCrData ◽  
2020 ◽  
Vol 5 (10) ◽  
Author(s):  
Erika Samolová ◽  
Jan Fábry
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Layered Structure ◽  
Title Complex ◽  
Water Molecules ◽  
X Ray ◽  
Positional Disorder ◽  
Coordination Numbers ◽  
Carboxylate Groups ◽  
Accuracy And Precision

The crystal structure of the title complex, [Pb3(C4H7O2)6(H2O)2] n , was redetermined on basis of modern CCD-based single-crystal X-ray data at 120 K. The current study basically confirms the previous report [Fallon et al. (1997). Polyhedron, 16, 19–23] at 190 K, but with higher accuracy and precision. In particular, positional disorder of one of the 2-methylpropanoate anions over two sets of sites was resolved, showing a refined ratio of the disorder components of 0.535 (9):0.465 (9). The three independent cations in the structure have coordination numbers of [7 + 1], [6 + 1], and [5 + 3], with O atoms belonging either to carboxylate groups or water molecules. This arrangement leads to the formation of sheets parallel to (\overline{1}01), whereby the hydrophobic 2-methylpropanyl groups of the anions are oriented above and below the hydrophilic sheets to form a layered structure. Within a sheet, hydrogen bonds of the type Owater—H...O are formed, whereas the hydrophobic groups between adjacent layers interact through van der Waals forces.

scholarly journals Spectral, Thermal, Crystal Structure, Hirshfeld Surface Analyses and Biological Activities of New Hydrazinium Dipicolinato Copper(II) Tetrahydrate

2019 ◽  
Vol 31 (8) ◽  
pp. 1755-1761
Author(s):  
K. Naresh ◽  
B.N. Sivasankar
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Single Crystal ◽  
Water Clusters ◽  
Hirshfeld Surface ◽  
Water Molecules ◽  
X Ray ◽  
Biological Studies ◽  
Calf Thymus ◽  
Hydrazinium Cation

A new copper complex of pyridine-2,6-dicarboxylate containing hydrazinium cation, formulated as (N2H5)2[Cu(PDC)2]·4H2O (PDC = pyridine-2,6-dicarboxylate) has been synthesized from copper(II) nitrate, hydrazine hydrate and pyridine-2,6-dicarboxylic acid as a single crystal and characterized by elemental analysis and spectroscopic (IR and UV-visible), thermal (TG/DTG), single crystal X-ray diffraction and biological studies. A six-coordinate complex with a distorted octahedral geometry around Cu(II) ion is proposed and confirmed by X-ray single crystal method. The structure reveals that two pyridine-2,6-dicarboxylate species acting as tridentate ligands and hydrazinium cation present as a counter ion along with non-coordinated four water molecules. The structural units of copper(II) is mutually held by the hydrogen bonds and π···π and C–O···π interactions. The copper(II) complex is connected to one another via O–H···O hydrogen bonds, forming water clusters, which plays an important role in the stabilization of the crystal structure. In the water clusters, the water molecules are trapped by the cooperative association of coordination interactions as well as hydrogen bonds. Both cation and anion interactions and crystal from various types of intermolecular contacts and their importance were explored using Hirshfeld surface analysis. This indicates that O···H/H···O interactions are the superior interactions conforming excessive H-bond in the molecular structure. The interaction of copper(II) complex with calf thymus DNA (CT-DNA) was investigated by electronic absorption spectroscopic technique. The electronic evidence strongly shows that the compound interacts with calf thymus through intercalation with a binding constant of Kb = 5.7 × 104 M–1.

Benzo-18-krone-6 -Acetonitril (1/2): Kristallisation und Tieftemperatur- Röntgenstrukturanalyse / Benzo-18 -crown-6 -Acetonitrile (1/2): Crystallization and Low-Temperature X-Ray Analysis

1998 ◽  
Vol 53 (12) ◽  
pp. 1528-1530 ◽  
Author(s):  
Karna Wijaya ◽  
Oliver Moers ◽  
Armand Blaschette ◽  
Peter G. Jones
Keyword(s):  
Crystal Structure ◽  
Low Temperature ◽  
Data Collection ◽  
Single Crystals ◽  
Title Complex ◽  
Monoclinic Space Group ◽  
Hydrogen Atoms ◽  
Space Group ◽  
X Ray ◽  
Mecn Solution

Abstract Benzo-18 -crown-6 -Acetonitrile (1/2), Crystal Structure Single crystals of the title complex resulted fortuitously during an attempt to co-crystallise MeN(SO2Me)2 with benzo-18-crown-6 from an MeCN solution at -30 °C. The crystal structure has been determined via data collection at -100 °C (monoclinic, space group P21/n, Z = 4). The nitrile molecules are located with their me­ thyl groups above and below the plane of the 18-membered crown ring, the Me hydrogen atoms being rotationally disordered about the MeCN axes; C(methyl)···O(crown) distances range from 309.4(3) to 384.9(3) pm.

scholarly journals Dynamics of Water in Crystal Hydrates

1967 ◽  
Vol 22 (9) ◽  
pp. 1440-1451 ◽  
Author(s):  
Ingo Berthold ◽  
Alarich Weiss
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Dynamical Behaviour ◽  
Water Molecules ◽  
Intensity Data ◽  
Two Dimensional ◽  
Fourier Synthesis ◽  
Hydrogen Atoms ◽  
X Ray ◽  
H Nmr

The crystal structure of Na2S2O6·2 H2O has been refined by means of single crystal X-ray intensity data. The structure of the isotypic Li2S2O6·2 H20 was also determined by single crystal studies. Two dimensional differential FOURIER synthesis revealed the approximate positions of the hydrogen atoms. From 1H-NMR investigations, the crystal structure, and information gained by IR spectroscopy the complete atomic arrangement in these two substances was obtained. The influence of the dynamical behaviour of the water molecules is taken into account in determining the hydrogen positions.

The crystal and molecular structure of guanine hydrochloride dehydrate

1965 ◽  
Vol 288 (1414) ◽  
pp. 418-439 ◽  
Keyword(s):  
Hydrogen Bonds ◽  
Least Squares Method ◽  
Three Dimensional ◽  
Water Molecules ◽  
Hydrogen Atoms ◽  
X Ray ◽  
Anisotropic Temperature ◽  
Chlorine Ions ◽  
Atomic Coordinates ◽  
Single Crystal Analysis

The structure of guanine hydrochloride monohydrate has been determined by X-ray single crystal analysis and the parameters (including anisotropic temperature vibrations) have been refined by the three-dimensional least squares method. The unit cell is monoclinic with a = 14.69 ± 0.01, b = 13.40 ± 0.01, c = 4.840 ± 0.005 Å; β = 93.8°± 0.1°; space group P 2 1 / a . For 1600 independent reflexions the final value of the agreement index R was 0.07 and the standard deviations of atomic coordinates are in the region of 0.0035 Å. Two guanine molecules are linked together by hydrogen bonds to form a centrosymmetrical dimer. The dimer is linked by hydrogen bonds to four water molecules which are then hydrogen bonded to two chlorine ions. It is shown that the guanine molecule has associated with it six centres of electron density corresponding to hydrogen atoms and it is therefore in the form (H guanine) + with protonation at the N 7 position.

Crystal Structure of Adeninium Trichloromercurate(II),

1975 ◽  
Vol 53 (15) ◽  
pp. 2345-2350 ◽  
Author(s):  
Monique Authier-Martin ◽  
André L. Beauchamp
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Least Squares ◽  
Title Compound ◽  
Heavy Atom ◽  
Chloride Ions ◽  
Water Molecules ◽  
Hydrogen Atoms ◽  
Space Group ◽  
Heavy Atom Method

The title compound belongs to space group P21/c with a = 23.99(1), b = 4.245(2), c = 25.98(1) Å, β = 117.58(7)°, and Z = 8. The structure was solved by the heavy-atom method and refined by block-diagonal least squares on 2589 independent observed reflections. All non-hydrogen atoms were refined anisotropically and some of the hydrogen atoms were located but their parameters were not refined. The final values of R and Rw were 0.042 and 0.047, respectively.The two nonequivalent mercury atoms have very similar environments. Two short Hg—Cl bonds (2.34–2.38 Å) at ∼ 165° define a quasi-molecular HgCl2 unit. Overall octahedral coordination is completed with two chloride ions at 2.76–2.84 Å and two chlorine atoms at 3.19–3.26 Å on neighboring HgCl2 quasi-molecules. HgCl6 octahedra share edges to form twofold ribbons in the b direction. This pattern of octahedra is identical with the onereported for β-NH4HgCl3. The cations are pairs of N(1)-protonated adenine molecules linked by two N(10)—H(10)… N(7) hydrogen bonds and stacked in the b direction. Water molecules act as acceptors in moderately strong hydrogen bonds with acidic protons H(1) and H(9) of adeninium ions. Other generally weaker hydrogen bonds exist between the various parts of the structure.

Low-temperature crystal structure of RS-thiocamphor

2004 ◽  
Vol 219 (9) ◽  
Author(s):  
E. Louise R. Robins ◽  
Michela Brunelli ◽  
Asiloé J. Mora ◽  
Andrew N. Fitch
Keyword(s):  
Crystal Structure ◽  
Phase Transitions ◽  
Low Temperature ◽  
Room Temperature ◽  
Cubic Phase ◽  
X Ray Diffraction ◽  
Orthorhombic Space Group ◽  
Two Phase ◽  
X Ray ◽  
Low Temperature Crystal Structure

AbstractDSC and high-resolution powder X-ray diffraction measurements in the range 295 K–100 K show that RS-thiocamphor undergoes two phase transitions. The first, at around 260 K on cooling, is from the room-temperature body-centred-cubic phase to a short-lived intermediate. At 258 K the low-temperature form starts to appear. The crystal structure of the latter is orthorhombic, space group

scholarly journals TheZ′ = 12 superstructure of Λ-cobalt(III) sepulchrate trinitrate governed by C—H...O hydrogen bonds

2016 ◽  
Vol 72 (3) ◽  
pp. 372-380 ◽  
Author(s):  
Somnath Dey ◽  
Andreas Schönleber ◽  
Swastik Mondal ◽  
Siriyara Jagannatha Prathapa ◽  
Sander van Smaalen ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Low Temperature ◽  
Hydrogen Bonds ◽  
Room Temperature ◽  
Structural Parameters ◽  
Molecular Packing ◽  
Nitrate Group ◽  
Structural Variations ◽  
Monoclinic Symmetry ◽  
Low Temperature Crystal Structure

Λ-Cobalt(III) sepulchrate trinitrate crystallizes inP6322 withZ= 2 (Z′ = 1/6) at room temperature. Slabs perpendicular to the hexagonal axis comprise molecules Co(sepulchrate) alternating with nitrate groupsAandB. Coordinated by six sepulchrate molecules, highly disordered nitrate groupsCare accommodated between the slabs. Here we report the fully ordered, low-temperature crystal structure of Co(sep)(NO3)3. It is found to be a high-Z′ structure withZ′ = 12 of the 12-fold 6a_{h}\times\sqrt{3}b_{h}\times c_{h} superstructure with monoclinic symmetryP21(cunique). Correlations between structural parameters are effectively removed by refinements within the superspace approach. Superstructure formation is governed by a densification of the packing in conjunction with ordering of nitrate groupC, the latter assuming different orientations for each of theZ′ = 12 independent copies in the superstructure. The Co(sep) moiety exhibits small structural variations over its 12 independent copies, while orientations of nitrate groupsAandBvary less than the orientations of the nitrate groupCdo. Molecular packing in the superstructure is found to be determined by short C—H...H—C contacts, with H...H distances of 2.2–2.3 Å, and by short C—H...O contacts, with H...O distances down to 2.2 Å. These contacts presumably represent weak C—H...O hydrogen bonds, but in any case they prevent further densification of the structure and strengthening of weak N—H...O hydrogen bonds with observed H...O distances of 2.4–2.6 Å.

Synthesis, structure and biological activity of four new picolinohydrazonamide derivatives

2020 ◽  
Vol 76 (7) ◽  
pp. 673-680
Author(s):  
Małgorzata Szczesio ◽  
Katarzyna Gobis ◽  
Izabela Korona-Głowniak ◽  
Ida Mazerant-Politowicz ◽  
Dagmara Ziembicka ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Biological Activity ◽  
Nmr Spectroscopy ◽  
Low Temperature ◽  
Hydrogen Bonds ◽  
Essential Role ◽  
X Ray Diffraction ◽  
X Ray ◽  
Zwitterionic Form ◽  
Solvent Molecules

Four new picolinohydrazonamide derivatives, namely, 6-methyl-N′-(morpholine-4-carbonothioyl)picolinohydrazonamide, C12H17N5OS, 6-chloro-N′-(morpholine-4-carbonothioyl)picolinohydrazonamide methanol monosolvate, C11H14ClN5OS·CH3OH, 6-chloro-N′-(4-phenylpiperazine-1-carbonothioyl)picolinohydrazonamide, C17H19ClN6S, and 6-chloropicolinohydrazonamide, C6H7ClN4, have been synthesized and characterized by NMR spectroscopy and single-crystal low-temperature X-ray diffraction. In addition, their antibacterial and anti-yeast activities have been determined. The first three compounds adopt the zwitterionic form in the crystal structure regardless of the presence or absence of solvent molecules in the structure. They also adopt the same symmetry, i.e. P21/c (P21/n), unlike the fourth structure which is chiral and has the space group P212121. For all the studied cases, intermolecular N—H...O and N—H...N hydrogen bonds play an essential role in the formation of the structures.

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