Hydroxyl Groups Functionalized Single Crystal of Copper(II)‐Porphyrin Complex for Electroreduction CO2 to CH4

ChemSusChem ◽  
2022 ◽  
Author(s):  
Ya Zhang ◽  
Qiang Zhou ◽  
Peng Wang ◽  
Yue Zhao ◽  
Feng Gong ◽  
...  
Keyword(s):  
Single Crystal ◽  
Hydroxyl Groups ◽  
Porphyrin Complex

H-bonding scheme in allactite: a combined single-crystal X-ray and neutron diffraction, optical absorption spectroscopy, FTIR and EPMA-WDS study

2016 ◽  
Vol 80 (5) ◽  
pp. 719-732 ◽  
Author(s):  
G. Diego Gatta ◽  
Ferdinando Bosi ◽  
Maria Teresa Fernandez Diaz ◽  
Ulf Hålenius
Keyword(s):  
Neutron Diffraction ◽  
Optical Absorption ◽  
Single Crystal ◽  
Absorption Spectroscopy ◽  
Structure Refinement ◽  
Site Occupancy ◽  
Optical Absorption Spectroscopy ◽  
Hydroxyl Groups ◽  
X Ray ◽  
Bonding Scheme

AbsatractThe crystal chemistry of allactite from Långban, Värmland (Sweden) was investigated by single-crystal X-ray and neutron diffraction, optical absorption spectroscopy, Fourier-transform infra-red spectroscopy (FTIR) and electron microprobe analysis by wavelength-dispersive spectroscopy (EPMA-WDS). The optical spectra indicate the presence of Mn in valence state 2+ only. Assuming 16 O atoms per formula unit, arsenic as As5+and the (OH) content calculated by charge balance, the resulting formula based on the EPMA-WDS data is (Mn2+6.73Ca0.13Mg0.12Zn0.02)∑7.00(As5+)2.00O16H8, very close to the ideal composition Mn7(AsO4)2(OH)8. In the unpolarized FTIR spectrum of allactite, fundamental (OH)-stretching bands are observed at 3236, 3288, 3387, 3446, 3484, 3562 and 3570 cm–1, suggesting that a number of OH environments, with different hydrogen bond strengths, occur in the structure. The neutron structure refinement shows that four independent H sites occur in allactite with full site occupancy, all as members of hydroxyl groups. The complex hydrogen-bonding scheme in the allactite structure is now well defined, with at least nine hydrogen bonds energetically favourable with mono-, bi- and trifurcated configurations.

scholarly journals Effect of pressure on the crystal structure of L-serine-I and the crystal structure of L-serine-II at 5.4 GPa

2005 ◽  
Vol 61 (1) ◽  
pp. 58-68 ◽  
Author(s):  
Stephen A. Moggach ◽  
David R. Allan ◽  
Carole A. Morrison ◽  
Simon Parsons ◽  
Lindsay Sawyer
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
Hydrogen Bonds ◽  
Single Crystal ◽  
Ambient Pressure ◽  
Crystal Form ◽  
Hydroxyl Groups ◽  
Orthorhombic Space Group ◽  
Crystal Forms ◽  
Hydrogen Bonded

The crystal structure of L-serine has been determined at room temperature at pressures between 0.3 and 4.8 GPa. The structure of this phase (hereafter termed L-serine-I), which consists of the molecules in their zwitterionic tautomer, is orthorhombic, space group P212121. The least compressible cell dimension (c), corresponds to chains of head-to-tail NH...carboxylate hydrogen bonds. The most compressible direction is along b, and the pressure-induced distortion in this direction takes the form of closing up voids in the middle of R-type hydrogen-bonded ring motifs. This occurs by a change in the geometry of hydrogen-bonded chains connecting the hydroxyl groups of the —CH2OH side chains. These hydrogen bonds are the longest conventional hydrogen bonds in the system at ambient pressure, having an O...O separation of 2.918 (4) Å and an O...O...O angle of 148.5 (2)°; at 4.8 GPa these parameters are 2.781 (11) and 158.5 (7)°. Elsewhere in the structure one NH...O interaction reaches an N...O separation of 2.691 (13) Å at 4.8 GPa. This is amongst the shortest of this type of interaction to have been observed in an amino acid crystal structure. Above 4.8 GPa the structure undergoes a single-crystal-to-single-crystal phase transition to a hitherto uncharacterized polymorph, which we designate L-serine-II. The OH...OH hydrogen-bonded chains of L-serine-I are replaced in L-serine-II by shorter OH...carboxyl interactions, which have an O...O separation of 2.62 (2) Å. This phase transition occurs via a change from a gauche to an anti conformation of the OH group, and a change in the NCαCO torsion angle from −178.1 (2)° at 4.8 GPa to −156.3 (10)° at 5.4 GPa. Thus, the same topology appears in both crystal forms, which explains why it occurs from one single-crystal form to another. The transition to L-serine-II is also characterized by the closing-up of voids which occur in the centres of other R-type motifs elsewhere in the structure. There is a marked increase in CH...O hydrogen bonding in both phases relative to L-serine-I at ambient pressure.

scholarly journals Crystal structure of 5-[(benzoyloxy)methyl]-5,6-dihydroxy-4-oxocyclohex-2-en-1-yl benzoate

2020 ◽  
Vol 76 (7) ◽  
pp. 1096-1100
Author(s):  
Theerachart Leepasert ◽  
Patchreenart Saparpakorn ◽  
Kittipong Chainok ◽  
Tanwawan Duangthongyou
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bonds ◽  
Single Crystal ◽  
Natural Product ◽  
Dihedral Angle ◽  
Absolute Configuration ◽  
Hydroxyl Groups ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ring Form

The crystal structure of the natural product zeylenone, C21H18O7, was confirmed by single-crystal X-ray diffraction. The crystal structure has three chiral centers at positions C1, C5 and C6 of the cyclohexanone ring, but the absolute configuration could not be determined reliably. The methyl benzoate and benzoyloxy substituents at positions C1 and C5 of the cyclohexenone ring are on the same side of the ring with the dihedral angle between their mean planes being 16.25 (10)°. These rings are almost perpendicular to the cyclohexenone ring. The benzoate groups and two hydroxyl groups on the cyclohexenone ring form strong hydrogen bonds to consolidate the crystal structure. In addition, weak C—H...O hydrogen bonds also contribute to the packing of the structure.

Towards clathrates. 2. The frozen states of hydration of tert-butanol

2018 ◽  
Vol 233 (1) ◽  
pp. 41-49 ◽  
Author(s):  
Lukasz Dobrzycki
Keyword(s):  
Single Crystal ◽  
Crystalline Phase ◽  
Ambient Pressure ◽  
Water System ◽  
Hydroxyl Group ◽  
Molar Ratio ◽  
Water Molecules ◽  
Hydroxyl Groups ◽  
Hydrogen Atoms ◽  
Ir Laser

AbstractA new crystal structure oftert-butanol and water crystallizing as the decahydrate is reported. The crystallization of the mixture in the desired molar ratio was performed in a capillary placed directly on a goniometer of a single crystal diffractometer at 200 K and ambient pressure using focused IR laser radiation. The crystals were grown while the melting zone formed by the IR laser was moved along the capillary. Usually the crystallization process should be long enough (hours) in order to obtain a good quality single crystal. However, in the case oftert-butanol decahydrate, such a long process led to separation of the ice and alcohol. Only fast crystallization taking tens of seconds allowed crystallization of the desired crystalline phase. In the decahydratetert-butanol molecules are located in channels formed by water molecules. Hydroxyl groups are anchored to the water framework via hydrogen bonds. All water molecules in the structure have hydrogen atoms disordered equally over two sites; the hydroxyl group is likewise disordered. This effect is observed at both, 200 K and 100 K. Raman spectra recorded for the crystalline phase suggest dynamic disorder at higher temperature, converting to static at lowerT. The decahydrate oftert-butanol, together with already known itsdi- andhepta-hydrates, display similar features to those observed for series oftert-butylamine hydrates. The latter structures behave as frozen steps of amine hydration observed as crystal structures leading, at maximum dilution, to hexagonal ice. Hydrates oftert-butanol nicely follow this tendency completing the relationship found for thetert-butylamine: water system.

scholarly journals Al5B12O25(OH) and Ga4InB12O25(OH) – two additional triel borates with the structure type M5B12O25(OH) (M = Ga, In)

2020 ◽  
Vol 75 (6-7) ◽  
pp. 605-613
Author(s):  
Daniela Vitzthum ◽  
Daniel S. Wimmer ◽  
Ingo Widmann ◽  
Hubert Huppertz
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Ir Spectroscopy ◽  
Single Crystal ◽  
Crystal Structures ◽  
Structure Type ◽  
Hydroxyl Groups ◽  
X Ray Diffraction ◽  
X Ray ◽  
High Pressure High Temperature

AbstractThe isotypic triel borates Al5B12O25(OH) and Ga4InB12O25(OH) were synthesized in a Walker-type multianvil apparatus under high-pressure/high-temperature conditions of 12.0 GPa/1400 °C and 12.3 GPa/1200 °C, respectively. The crystal structures of both compounds, determined by single-crystal X-ray diffraction, constitute new representatives of the structure type M5B12O25(OH) (M = Ga, In) crystallizing in the space group I41/acd. The presence of the hydroxyl groups was confirmed via single-crystal IR spectroscopy.

On the complex H-bonding network in paravauxite, Fe2+Al2(PO4)2(OH)2·8H2O: A single-crystal neutron diffraction study

2014 ◽  
Vol 78 (4) ◽  
pp. 841-850 ◽  
Author(s):  
G. D. Gatta ◽  
P. Vignola ◽  
M. Meven
Keyword(s):  
Neutron Diffraction ◽  
Single Crystal ◽  
Structure Refinement ◽  
Neutron Diffraction Study ◽  
Hydroxyl Groups ◽  
Statistical Index ◽  
Raman And Infrared Spectroscopy ◽  
Difference Fourier ◽  
Experimental Findings ◽  
Rare Opportunity

AbstractThe crystal structure and the chemical composition of a paravauxite from the Siglo Veinte Mine, Llallagua, Bustillo Province, Potosi Department, Bolivia [Fe(Fe0.9162+Mn0.0162+Mg0.064Ca0.002)∑0.998Al(1)Al(2)Al2.005P(P1.998Si0.002)∑2O8(OH)2·8H2O, a = 5.242(1) Å, b = 10.569(2) Å, c = 6.970(2) Å, α = 106.78(3)°, β = 110.81(2)° and γ = 72.29(2)°, space group P], was investigated by single-crystal neutron diffraction and electron microprobe analysis in wavelength-dispersive mode. Neutron-intensity data were collected at 293 K and anisotropic structure refinement was performed. At the end of the refinement no peak larger than ±1.3 fm/Å3 was present in the final difference-Fourier map of the nuclear density. The final statistical index was R1 = 0.0495 for 194 refined parameters and 1678 unique reflections with Fo > 4σ(Fo). Eleven independent H sites (i.e. H(1), H(2), H(3), H(4A), H(4B), H(5), H(6), H(7), H(8), H(9A) and H(9B)), all at ∼1 Å from the respective O sites, were located successfully. H(4A) and H(4B) and H(9A) and H(9B) are two mutually exclusive subsite couples only 0.4−0.6 Å apart. The complex H-bonding scheme in the paravauxite structure is now well defined and 12 independent H bonds, with an energetically favourable bonding configuration, are described. A comparison between the previous experimental findings based on Raman and infrared spectroscopy and those obtained in this present study is carried out. Paravauxite provides the rare opportunity to investigate the H-bond configuration of coexisting hydroxyl groups and H2O molecules in minerals by single-crystal neutron diffraction. H2O is present as zeolitic (i.e. lying in the cavities) and non-zeolitic H2O (i.e. bonded to Al or Fe to form Al or Fe octahedra).

Location of argon and water in cordierite

1962 ◽  
Vol 33 (258) ◽  
pp. 226-236 ◽  
Author(s):  
J. V. Smith ◽  
W. Schreyer
Keyword(s):  
Single Crystal ◽  
Powder Diffraction ◽  
Diffraction Data ◽  
Water Molecules ◽  
Hydroxyl Groups ◽  
Powder Diffraction Data ◽  
X Ray ◽  
Cordierite Structure

SummaryEvaluation of X-ray powder diffraction data shows that argon atoms (radius 1·9 Å) lie at the centres of the large holes in the cordierite structure. The reflection intensities for hydrous cordierite differ from those for anhydrous cordierite but to a lesser degree than those for argon-bearing cordierite. Although analysis is uncertain, it appears that the smaller water molecules (radius 1·4 Å) do not occupy either the centres of the six-membered rings or the centres of the large cavities. It is possible that they may be attached to the walls of the large cavities or occur partly as hydroxyl groups in the framework. Single-crystal X-ray analysis is necessary to resolve this problem.

A Preparation of High Resolution Standards for Electron Microscopy. Part II

1971 ◽  
Vol 29 ◽  
pp. 160-161
Author(s):  
Akira Tanaka ◽  
David F. Harling
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Carbon Black ◽  
Single Crystal ◽  
Dark Field ◽  
Graphitized Carbon Black ◽  
Graphitized Carbon ◽  
Dark Field Imaging ◽  
Crystal Films ◽  
Micro Holes

In the previous paper, the author reported on a technique for preparing vapor-deposited single crystal films as high resolution standards for electron microscopy. The present paper is intended to describe the preparation of several high resolution standards for dark field microscopy and also to mention some results obtained from these studies. Three preparations were used initially: 1.) Graphitized carbon black, 2.) Epitaxially grown particles of different metals prepared by vapor deposition, and 3.) Particles grown epitaxially on the edge of micro-holes formed in a gold single crystal film.The authors successfully obtained dark field micrographs demonstrating the 3.4Å lattice spacing of graphitized carbon black and the Au single crystal (111) lattice of 2.35Å. The latter spacing is especially suitable for dark field imaging because of its preparation, as in 3.), above. After the deposited film of Au (001) orientation is prepared at 400°C the substrate temperature is raised, resulting in the formation of many square micro-holes caused by partial evaporation of the Au film.

Structure of Palladium Single-Crystal Films Prepared by Flash Evaporation onto (001) NaCl Substrates

1970 ◽  
Vol 28 ◽  
pp. 456-457
Author(s):  
L. E. Murr ◽  
G. Wong
Keyword(s):  
Single Crystal ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
High Rate ◽  
Flash Evaporation ◽  
Optimum Load ◽  
Single Crystal Films ◽  
Crystal Films ◽  
A Current

Palladium single-crystal films have been prepared by Matthews in ultra-high vacuum by evaporation onto (001) NaCl substrates cleaved in-situ, and maintained at ∼ 350° C. Murr has also produced large-grained and single-crystal Pd films by high-rate evaporation onto (001) NaCl air-cleaved substrates at 350°C. In the present work, very large (∼ 3cm2), continuous single-crystal films of Pd have been prepared by flash evaporation onto air-cleaved (001) NaCl substrates at temperatures at or below 250°C. Evaporation rates estimated to be ≧ 2000 Å/sec, were obtained by effectively short-circuiting 1 mil tungsten evaporation boats in a self-regulating system which maintained an optimum load current of approximately 90 amperes; corresponding to a current density through the boat of ∼ 4 × 104 amperes/cm2.

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