Stable Molecular Complex of Squaric Acid with 2-(Quinuclidinium)propionate

2013 ◽  
Vol 66 (7) ◽  
pp. 836 ◽  
Author(s):  
Zofia Dega-Szafran ◽  
Andrzej Katrusiak ◽  
Miroslaw Szafran
Keyword(s):  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Squaric Acid ◽  
X Ray Diffraction ◽  
Broad Absorption ◽  
Functional Theory ◽  
X Ray ◽  
State Aggregation ◽  
Ir Frequencies ◽  
Nmr Techniques

Squaric acid (3,4-dihydroxy-3-cyclobuten-1,2-dione, H2SQ) forms a complex with 2-(quinuclidinium)propionate (QNPr). In crystals, the molecules of H2SQ and zwitterions of QNPr are bridged by two strong non-equivalent O–H⋯O hydrogen bonds of 2.476(2) and 2.482(1) Å. The complex is investigated by X-ray diffraction, FTIR, and NMR techniques, and the results are supported by density functional theory calculations. The solid-state aggregation is consistent with the NMR results, recorded for an aqueous solution, and is also reproduced for the structure optimized at the B3LYP/6-311++G(d,p) level of theory. The calculated IR frequencies for the optimized structure have been used for the assignment of the experimental FTIR spectrum, where the broad absorption at ~2400 cm–1 corresponds to the short asymmetric OH⋯O bonds.

A high-pressure study of HfC and nano-crystalline TiC by X-ray diffraction and density functional theory calculations

2020 ◽  
Vol 34 (34) ◽  
pp. 2050393
Author(s):  
Lun Xiong ◽  
Bin Li ◽  
Bi Liang ◽  
Jinxia Zhu ◽  
Hong Yi ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
High Pressure ◽  
Bulk Modulus ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
X Ray ◽  
Nano Crystalline

The equation of state (EOS) of HfC and nanosized TiC at high pressure has been studied by means of synchrotron radiation X-ray diffraction (XRD) in a diamond anvil cell (DAC) at ambient temperature, and density functional theory (DFT) calculations. XRD analysis showed that the cubic structure of HfC and nanosized TiC maintained to the maximum pressures. The XRD data yield a bulk modulus [Formula: see text] GPa with [Formula: see text] of HfC. In addition, the bulk modulus of nanosized TiC derived from XRD data is [Formula: see text] GPa with [Formula: see text].

Investigation of Structural Evolution of Li1.1V3O8 by In Situ X-ray Diffraction and Density Functional Theory Calculations

2017 ◽  
Vol 29 (5) ◽  
pp. 2364-2373 ◽  
Author(s):  
Qing Zhang ◽  
Alexander B. Brady ◽  
Christopher J. Pelliccione ◽  
David C. Bock ◽  
Andrea M. Bruck ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Density Functional ◽  
Structural Evolution ◽  
Density Functional Theory Calculations ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
X Ray

scholarly journals Experimental and theoretical charge density distribution in Pigment Yellow 101

2015 ◽  
Vol 17 (6) ◽  
pp. 4677-4686 ◽  
Author(s):  
Jonathan J. Du ◽  
Linda Váradi ◽  
Jinlong Tan ◽  
Yiliang Zhao ◽  
Paul W. Groundwater ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Density Distribution ◽  
Charge Density ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
X Ray Diffraction ◽  
Charge Density Distribution ◽  
Functional Theory ◽  
X Ray ◽  
Multipole Refinement

The charge density distribution in 2,2′-dihydroxy-1,1′-naphthalazine (Pigment Yellow 101; P.Y.101) has been determined using high-resolution X-ray diffraction and multipole refinement, along with density functional theory calculations.

Meso-1,4-phenylene bridged nickel norcorrole dimer

2020 ◽  
Vol 24 (01n03) ◽  
pp. 191-199
Author(s):  
Ji-Young Shin
Keyword(s):  
Density Functional ◽  
Spectroscopic Analysis ◽  
Computational Simulation ◽  
Density Functional Theory Calculations ◽  
Laser Pulses ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
X Ray ◽  
Solid States ◽  
Anti Conformation

Nickel norcorrole dimer 3 linked with a phenylene bridge was prepared by a nickel-mediated homolytic cross-coupling of meso-phenylene bisdipyrrin nickel(II) dimer 2b. The structures of 2b and 3 were elucidated by X-ray diffraction analysis. Each nickel norcorrole fraction of the nickel norcorrole dimer 3 exposed a bowl-like structure, which conserved anti-conformation. Structural distinctions between the monomeric and dimeric nickel norcorroles were established by vibrational spectroscopic analysis and assessed with density functional theory calculations. Enhanced flexibility of the norcorrole planes in solution states of monomeric nickel norcorrole was compromised to that of bowl-shaped norcorroles in the solid states of nickel norcorrole dimer 3, where C[Formula: see text] was the formulated conformation. The deformation of the planarity derived from the objection of laser pulses effectuated vibration shifts of specific Raman-active motions toward a higher-frequency region, as associating with a paratropic nature of the [Formula: see text]-electron delocalization circuit of norcorrole. Computational simulation exposed a reliable drift of the Raman frequencies.

scholarly journals Hydrosilyation of CO2 using a silatrane hydride: structural characterization of a silyl formate compound

2021 ◽  
Vol 99 (2) ◽  
pp. 259-267
Author(s):  
Serge Ruccolo ◽  
Erika Amemiya ◽  
Daniel G. Shlian ◽  
Gerard Parkin
Keyword(s):  
Molecular Structure ◽  
Density Functional Theory ◽  
Oxygen Atom ◽  
Structural Characterization ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
X Ray

The silatrane hydride compound, [N(CH2CH2O)3]SiH, reacts with CO2 in the presence of the [tris(2-pyridylthio)methyl]zinc hydride complex, [Tptm]ZnH, to afford the silyl formate and methoxide derivatives, [N(CH2CH2O)3]SiO2CH and [N(CH2CH2O)3]SiOCH3. The molecular structure of [N(CH2CH2O)3]SiO2CH has been determined by X-ray diffraction, thereby demonstrating that the formate ligand adopts a distal conformation in which the uncoordinated oxygen atom resides with a trans-like disposition relative to silicon. Density functional theory calculations indicate that the atrane motif of [N(CH2CH2O)3]SiO2CH is flexible, such that the energy of the molecule changes relatively little as the Si···N distance varies over the range 2.0–3.0 Å.

The crystal structure of Zr2NiD4.5

2006 ◽  
Vol 62 (6) ◽  
pp. 972-978 ◽  
Author(s):  
M. H. Sørby ◽  
A. E. Gunnæs ◽  
O. M. Løvvik ◽  
H. W. Brinks ◽  
H. Fjellvåg ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Neutron Diffraction Data ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
X Ray ◽  
Tetrahedral Sites ◽  
Powder Neutron Diffraction ◽  
Powder Neutron Diffraction Data

The crystal structure of Zr2NiD4.5 has been determined by a combination of synchrotron radiation powder X-ray diffraction, electron diffraction and powder neutron diffraction data. Deuterium ordering results in a triclinic supercell given by a super = 6.81560 (7), b super = 8.85137 (9), c super = 8.88007 (10) Å, αsuper = 79.8337 (8), βsuper = 90.0987 (9), γsuper = 90.3634 (9)°, which relates to the non-super unit cell as a super = −a, b super = −b − c, c super = −b + c. The centrosymmetric and fully ordered deuterium sublattice was determined by simulated annealing and Rietveld refinement. Deuterium was found to occupy three types of tetrahedral sites: two that are coordinated by four Zr atoms and one that is coordinated by three Zr atoms and one Ni atom. All D—D distances are longer than 2 Å. The feasibility of the crystal structure was supported by density functional theory calculations.

scholarly journals Boosting the Stability of Boron Peroxides through Subphthalocyanine Coordination

2021 ◽  
Vol 03 (02) ◽  
pp. 141-145
Author(s):  
Jorge Labella ◽  
Elisa López-Serrano ◽  
Tomás Torres
Keyword(s):  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Lewis Base ◽  
Ambient Conditions ◽  
X Ray Diffraction ◽  
Functional Theory ◽  
X Ray ◽  
The Stability ◽  
The Impact ◽  
Structural And Optoelectronic Properties

The great potential of subphthalocyanines (SubPcs) to stabilize boron peroxides has been demonstrated. In particular, a subphthalocyanato boron (III) peroxide has been prepared in good yield via boron triflate. This derivative is remarkably stable under ambient conditions and can be fully characterized. The impact of the peroxide group on the structural and optoelectronic properties of SubPc was examined by NMR and UV/Vis spectroscopies, as well as single-crystal X-ray diffraction analysis. Moreover, density functional theory calculations were performed to explain the experimental results. The reactivity of this peculiar boron peroxide as an oxidant and a Lewis base was also studied.

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