On the crystal structures and hydrogen bond patterns in proline pseudopolymorphs

2010 ◽  
Vol 25 (3) ◽  
pp. 235-240 ◽  
Author(s):  
Luis E. Seijas ◽  
Gerzon E. Delgado ◽  
Asiloé J. Mora ◽  
Andrew N. Fitch ◽  
Michela Brunelli

Amino acids often cocrystallize with water molecules, which make them pseudopolymorphs of their anhydrous forms. In this work, we discuss in detail the hydrogen bond patterns in anhydrous L-proline and DL-proline and its pseudopolymorphic forms: L-proline monohydrate and DL-proline monohydrate. For this propose, the crystal structure of L-proline anhydrous was determined from synchrotron X-ray powder diffraction data and refined using the Rietveld method. Special emphasis is given to the role played by the water molecule in the hydrogen bond network observed in the crystalline structures.

2007 ◽  
Vol 63 (11) ◽  
pp. i185-i185 ◽  
Author(s):  
Wei Liu ◽  
Jingtai Zhao

The title compound, ammonium catena-[monoboro-monodihydrogendiborate-monohydrogenphosphate] hemihydrate, was obtained under solvothermal conditions using glycol as the solvent. The crystal structure is constructed of one-dimensional infinite borophosphate chains, which are interconnected by ammonium ions and water molecules via a complex hydrogen-bond network to form a three-dimensional structure. The water molecules of crystallization are disordered over inversion centres, and their H atoms were not located.


2015 ◽  
Vol 30 (2) ◽  
pp. 170-174
Author(s):  
James A. Kaduk ◽  
Kai Zhong ◽  
Thomas N. Blanton

The crystal structure of rilpivirine has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional techniques. Rilpivirine crystallizes in space group P21/c (#14) with a = 8.39049(3), b = 13.89687(4), c = 16.03960(6) Å, β = 90.9344(3)°, V = 1869.995(11) Å3, and Z = 4. The most prominent features of the structure are N–H···N hydrogen bonds. These form a R2,2(8) pattern which, along with C1,1(12) and longer chains, yield a three-dimensional hydrogen bond network. The powder pattern has been submitted to International Centre for Diffraction Data, ICDD, for inclusion in future releases of the Powder Diffraction File™.


2021 ◽  
pp. 1-7
Author(s):  
James A. Kaduk ◽  
Amy M. Gindhart ◽  
Thomas N. Blanton

The crystal structure of edoxaban tosylate monohydrate has been solved and refined using synchrotron X-ray powder diffraction data, and optimized using density functional techniques. Edoxaban tosylate monohydrate crystallizes in space group P21 (#4) with a = 7.55097(2), b = 7.09010(2), c = 32.80420(21) Å, β = 96.6720(3)°, V = 1744.348(6) Å3, and Z = 2. The crystal structure consists of alternating layers of edoxaban cations and tosylate anions along the c-axis. The water molecules lie near the sulfonate end of the tosylate anions. The solid-state conformation of the edoxaban cation is determined by intermolecular interactions. The protonated nitrogen atom forms a strong N–H⋯O hydrogen bond to one of the tosylate oxygens. Only one of the water molecule hydrogens acts as a donor in an O–H⋯O hydrogen bond. The tosylate oxygens act as acceptors in a number of C–H⋯O hydrogen bonds. The powder pattern has been submitted to ICDD® for inclusion in the Powder Diffraction File™.


RSC Advances ◽  
2019 ◽  
Vol 9 (18) ◽  
pp. 10058-10063 ◽  
Author(s):  
Seyedayat Ghazisaeed ◽  
Boris Kiefer ◽  
Jakub Plášil

The complete crystal structure, including the hydrogen bond network, of lead uranyl-oxide mineral curite, ideally Pb3(H2O)2[(UO2)4O4(OH)3]2, was resolved by combining single-crystal X-ray diffraction and theory.


2007 ◽  
Vol 22 (1) ◽  
pp. 64-67
Author(s):  
Kunihisa Sugimoto ◽  
Robert E. Dinnebier ◽  
Thomas Schlecht

In the course of an investigation of cracks in certain magnesia floors containing the mineral chlorartinite [Mg2(CO3)(H2O)(OH)]Cl·H2O, the dehydration process of chlorartinite was carried out in high vacuum. The crystal structure of dehydrated chlorartinite [Mg2(CO3)(H2O)(OH)]Cl was refined from laboratory X-ray powder diffraction data using the Rietveld method [R3c, a=22.6791(5) Å, c=7.22336(14) Å, V=3217.52(11) Å3, Z=18, Rp=4.13%, Rwp=5.82%]. Dehydrated chlorartinite exhibits the same type of 3D honeycomb zeolite-like crystal structure with large channels as the hydrated form. Compared to the hydrated form, the channels of dehydrated chlorartinite are empty because of the removal of all non-coordinating water molecules with the cell volume shrinking by 4.0%, leading to a more distorted environment of the magnesium atoms.


2009 ◽  
Vol 419 (2) ◽  
pp. 339-345 ◽  
Author(s):  
Hideaki Sato ◽  
Masakazu Sugishima ◽  
Hiroshi Sakamoto ◽  
Yuichiro Higashimoto ◽  
Chizu Shimokawa ◽  
...  

HO (haem oxygenase) catalyses the degradation of haem to biliverdin, CO and ferrous iron via three successive oxygenation reactions, i.e. haem to α-hydroxyhaem, α-hydroxyhaem to α-verdohaem and α-verdohaem to ferric biliverdin–iron chelate. In the present study, we determined the crystal structure of ferrous α-verdohaem–rat HO-1 complex at 2.2 Å (1 Å=0.1 nm) resolution. The overall structure of the verdohaem complex was similar to that of the haem complex. Water or OH− was co-ordinated to the verdohaem iron as a distal ligand. A hydrogen-bond network consisting of water molecules and several amino acid residues was observed at the distal side of verdohaem. Such a hydrogen-bond network was conserved in the structures of rat HO-1 complexes with haem and with the ferric biliverdin–iron chelate. This hydrogen-bond network may act as a proton donor to form an activated oxygen intermediate, probably a ferric hydroperoxide species, in the degradation of α-verdohaem to ferric biliverdin–iron chelate similar to that seen in the first oxygenation step.


2021 ◽  
pp. 1-6
Author(s):  
Mariana M. V. M. Souza ◽  
Alex Maza ◽  
Pablo V. Tuza

In the present work, LaNi0.5Ti0.45Co0.05O3, LaNi0.45Co0.05Ti0.5O3, and LaNi0.5Ti0.5O3 perovskites were synthesized by the modified Pechini method. These materials were characterized using X-ray fluorescence, scanning electron microscopy, and powder X-ray diffraction coupled to the Rietveld method. The crystal structure of these materials is orthorhombic, with space group Pbnm (No 62). The unit-cell parameters are a = 5.535(5) Å, b = 5.527(3) Å, c = 7.819(7) Å, V = 239.2(3) Å3, for the LaNi0.5Ti0.45Co0.05O3, a = 5.538(6) Å, b = 5.528(4) Å, c = 7.825(10) Å, V = 239.5(4) Å3, for the LaNi0.45Co0.05Ti0.5O3, and a = 5.540(2) Å, b = 5.5334(15) Å, c = 7.834(3) Å, V = 240.2(1) Å3, for the LaNi0.5Ti0.5O3.


2010 ◽  
Vol 25 (3) ◽  
pp. 247-252 ◽  
Author(s):  
F. Laufek ◽  
J. Návrátil

The crystal structure of skutterudite-related phase IrGe1.5Se1.5 has been refined by the Rietveld method from laboratory X-ray powder diffraction data. Refined crystallographic data for IrGe1.5Se1.5 are a=12.0890(2) Å, c=14.8796(3) Å, V=1883.23(6) Å3, space group R3 (No. 148), Z=24, and Dc=8.87 g/cm3. Its crystal structure can be derived from the ideal skutterudite structure (CoAs3), where Se and Ge atoms are ordered in layers perpendicular to the [111] direction of the original skutterudite cell. Weak distortions of the anion and cation sublattices were also observed.


2014 ◽  
Vol 70 (a1) ◽  
pp. C901-C901
Author(s):  
Solveig Madsen ◽  
Jacob Overgaard ◽  
Bo Iversen

Intramolecular electron transfer (ET) in mixed valence (MV) oxo-centered [FeiiFeiii2O(carboxylate)6(ligand)3]·solvent complexes is highly dependent on temperature, on the nature of the ligands, and on the presence of crystal solvent molecules [1]. Whereas the effects of temperature, crystal solvent, and ligand variation on the details of the ET have been explored thoroughly, the effect of pressure is less well described [2]. The effect of pressure on the ET in MV Fe3O(cyanoacetate)6(water)3has been investigated with single crystal X-ray diffraction and Mössbauer spectroscopy. Previous multi-temperature studies have shown that at room temperature the ET between the three Fe sites is fast and the observed structure of the Fe3core is a perfectly equilateral triangle [3]. Cooling the complex below 130 K induces a phase transition as the ET slows down. Below 120 K the Fe3core is distorted due to the localization of the itinerant electron on one of the three Fe sites in the triangle (the complex is then in the valence trapped state). The valence trapping is complete within a temperature interval of just 10 K. The abruptness of the transition has been attributed to the extended hydrogen bond network involving water ligands and cyano groups, promoting intermolecular cooperative effects. The high-pressure X-ray diffraction data show that there is a 900flip of half the cyano groups at 3.5 GPa, which dramatically changes the hydrogen bond network. At a slightly higher pressure, a phase transition is found to occur. The five single crystals investigated all broke into minor fragments at the transition; however triclinic unit cells, similar to the low temperature unit cell, could be indexed from selected spots. Additional evidence that the complex is valence trapped comes from high pressure Mössbauer spectra measured above the phase transition (4 GPa). The relationship between valence trapping and the structural changes will in this work be highlighted using void space and Hirshfeld surface analysis.


2021 ◽  
Vol 91 (11) ◽  
pp. 2176-2186
Author(s):  
G. S. Tsebrikova ◽  
Yu. I. Rogacheva ◽  
I. S. Ivanova ◽  
A. B. Ilyukhin ◽  
V. P. Soloviev ◽  
...  

Abstract 2-Hydroxy-5-methoxyphenylphosphonic acid (H3L1) and the complex [Cu(H2L1)2(H2O)2] were synthesized and characterized by IR spectroscopy, thermogravimetry, and X-ray diffraction analysis. The polyhedron of the copper atom is an axially elongated square bipyramid with oxygen atoms of phenolic and of monodeprotonated phosphonic groups at the base and oxygen atoms of water molecules at the vertices. The protonation constants of the H3L1 acid and the stability constants of its Cu2+ complexes in water were determined by potentiometric titration. The protonation constants of the acid in water are significantly influenced by the intramolecular hydrogen bond and the methoxy group. The H3L1 acid forms complexes CuL‒ and CuL24‒ with Cu2+ in water.


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