scholarly journals Single-crystal X-ray diffraction and NMR crystallography of a 1:1 cocrystal of dithianon and pyrimethanil

2017 ◽  
Vol 73 (3) ◽  
pp. 149-156 ◽  
Author(s):  
Ann-Christin Pöppler ◽  
Emily K. Corlett ◽  
Harriet Pearce ◽  
Mark P. Seymour ◽  
Matthew Reid ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Chemical Shifts ◽  
Magic Angle Spinning ◽  
Mas Nmr ◽  
Double Quantum ◽  
Magic Angle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Nmr Crystallography

A single-crystal X-ray diffraction structure of a 1:1 cocrystal of two fungicides, namely dithianon (DI) and pyrimethanil (PM), is reported [systematic name: 5,10-dioxo-5H,10H-naphtho[2,3-b][1,4]dithiine-2,3-dicarbonitrile–4,6-dimethyl-N-phenylpyrimidin-2-amine (1/1), C14H4N2O2S2·C12H13N2]. Following an NMR crystallography approach, experimental solid-state magic angle spinning (MAS) NMR spectra are presented together with GIPAW (gauge-including projector augmented wave) calculations of NMR chemical shieldings. Specifically, experimental 1H and 13C chemical shifts are determined from two-dimensional 1H–13C MAS NMR correlation spectra recorded with short and longer contact times so as to probe one-bond C—H connectivities and longer-range C...H proximities, whereas H...H proximities are identified in a 1H double-quantum (DQ) MAS NMR spectrum. The performing of separate GIPAW calculations for the full periodic crystal structure and for isolated molecules allows the determination of the change in chemical shift upon going from an isolated molecule to the full crystal structure. For the 1H NMR chemical shifts, changes of 3.6 and 2.0 ppm correspond to intermolecular N—H...O and C—H...O hydrogen bonding, while changes of −2.7 and −1.5 ppm are due to ring current effects associated with C—H...π interactions. Even though there is a close intermolecular S...O distance of 3.10 Å, it is of note that the molecule-to-crystal chemical shifts for the involved sulfur or oxygen nuclei are small.

scholarly journals High-temperature in situ crystallographic observation of reversible gas sorption in impermeable organic cages

2015 ◽  
Vol 112 (46) ◽  
pp. 14156-14161 ◽  
Author(s):  
Seung Bin Baek ◽  
Dohyun Moon ◽  
Robert Graf ◽  
Woo Jong Cho ◽  
Sung Woo Park ◽  
...  
Keyword(s):  
Single Crystal ◽  
High Temperatures ◽  
Direct Detection ◽  
Variable Temperature ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
X Ray Diffraction ◽  
X Ray ◽  
Dynamic Motion

Crystallographic observation of adsorbed gas molecules is a highly difficult task due to their rapid motion. Here, we report the in situ single-crystal and synchrotron powder X-ray observations of reversible CO2 sorption processes in an apparently nonporous organic crystal under varying pressures at high temperatures. The host material is formed by hydrogen bond network between 1,3,5-tris-(4-carboxyphenyl)benzene (H3BTB) and N,N-dimethylformamide (DMF) and by π–π stacking between the H3BTB moieties. The material can be viewed as a well-ordered array of cages, which are tight packed with each other so that the cages are inaccessible from outside. Thus, the host is practically nonporous. Despite the absence of permanent pathways connecting the empty cages, they are permeable to CO2 at high temperatures due to thermally activated molecular gating, and the weakly confined CO2 molecules in the cages allow direct detection by in situ single-crystal X-ray diffraction at 323 K. Variable-temperature in situ synchrotron powder X-ray diffraction studies also show that the CO2 sorption is reversible and driven by temperature increase. Solid-state magic angle spinning NMR defines the interactions of CO2 with the organic framework and dynamic motion of CO2 in cages. The reversible sorption is attributed to the dynamic motion of the DMF molecules combined with the axial motions/angular fluctuations of CO2 (a series of transient opening/closing of compartments enabling CO2 molecule passage), as revealed from NMR and simulations. This temperature-driven transient molecular gating can store gaseous molecules in ordered arrays toward unique collective properties and release them for ready use.

scholarly journals SYSU-6, A New 2-D Aluminophosphate Zeolite Layer Precursor

Molecules ◽  
2019 ◽  
Vol 24 (16) ◽  
pp. 2972 ◽  
Author(s):  
Jiang-Zhen Qiu ◽  
Long-Fei Wang ◽  
Jiuxing Jiang
Keyword(s):  
Electron Microscopy ◽  
Single Crystal ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
X Ray Diffraction ◽  
Structure Directing Agent ◽  
X Ray ◽  
Uv Raman ◽  
Angle Spinning ◽  
Inorganic Framework

Two-dimensional aluminophosphate is an important precursor of phosphate-based zeolites; a new Sun Yat-sen University No. 6 (SYSU-6) with |Hada|2[Al2(HPO4)(PO4)2] has been synthesized in the hydrothermal synthesis with organic structure-directing agent (OSDA) of N,N,3,5-tetramethyladamantan-1-amine. In this paper, SYSU-6 is characterized by single-crystal/powder X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray analysis, transmission electron microscopy, infrared and UV Raman spectroscopy, solid-state 27Al, 31P and 13C magic angle spinning (MAS) NMR spectra, and elemental analysis. The single-crystal X-ray diffraction structure indicates that SYSU-6 crystallized in the space group P21/n, with a = 8.4119(3), b = 36.9876(12), c = 12.5674(3), α = 90°, β = 108.6770(10)°, γ = 90°, V = 3704.3(2) Å3, Z = 4, R = 5.12%, for 8515 observed data (I > 2σ(I)). The structure has a new 4,12-ring layer framework topology linked by alternating AlO4 and PO4 tetrahedra. The organic molecules reside between the layers and are hydrogen-bonded to the inorganic framework. The new type of layer provides a greater opportunity to construct zeolite with novel topology.

Single-crystal structure analysis of a novel aryl phosphinate diglycidyl ether

1999 ◽  
Vol 55 (4) ◽  
pp. 525-529 ◽  
Author(s):  
Ching-Sheng Cho ◽  
Wen-Bin Liau ◽  
Leo-Wang Chen
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Chemical Shifts ◽  
Glycidyl Ether ◽  
Diglycidyl Ether ◽  
Crystal Structure Analysis ◽  
Epoxide Ring ◽  
X Ray Diffraction ◽  
X Ray ◽  
Single Crystal Structure Analysis

The crystal structure of 10-[2,5-bis(2,3-epoxy-1-propoxy)phenyl]-9-oxa-10-phosphaphenanthren-10-one has been studied by single-crystal X-ray diffraction. The unit cell of C24H21O6P, M r = 436.4, is triclinic, P1¯, with a = 8.507 (3), b = 10.613 (4), c = 12.457 (3) Å, α = 80.05 (3), β = 71.38 (2), γ = 76.69 (3)°, V = 1031.1 (6) Å3, Z = 2, D x = 1.406 Mg m−3 and μ(Mo Kα) = 0.17 mm−1. The final R (wR) is 0.063 (0.057) {w = 1/[σ2(F) + 0.0004F 2]} for 3619 unique reflections measured at 295 K. The aryl phosphinate group bonded to the central phenyl ring comes close to one of the two glycidyl ether groups, the epoxide ring of which is ordered. The epoxide ring far from the aryl phosphinate group is disordered. The NMR chemical shifts of the protons of the glycidyl ether group close to the aryl phosphinate group are reduced by the `ring-current effect'.

Mixed Carbides via Polymer Route

1990 ◽  
Vol 180 ◽  
Author(s):  
Gian D. Soraru ◽  
Florence Babonneau ◽  
John D. Mackenzie
Keyword(s):  
Magic Angle Spinning ◽  
Transformation Process ◽  
Mas Nmr ◽  
Magic Angle ◽  
Pyrolysis Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Metallic Element ◽  
Angle Spinning

ABSTRACTSeveral polymetallocarbosilanes, pre-ceramics precursors for Si-M-C-O systems, have been prepared from polycarbosilane and metallic alkoxides, M(OR)n with M = Ti, Zr and Al. Polymers have essentially been characterized by Magic Angle Spinning Nuclear Magnetic Resonance (MAS-NMR). The pyrolysis process has been followed for each system with X-Ray Diffraction (XRD) and MAS-NMR. The role of the metallic element M on the transformation process of these systems will be discussed.

Precipitation of Mixed-Alkali Molybdates During HLW Vitrification

2010 ◽  
Vol 1265 ◽  
Author(s):  
Scott Kroeker ◽  
Carolyn Higman ◽  
Vladimir K Michaelis ◽  
Nicholas B Svenda ◽  
Sophie Schuller
Keyword(s):  
Nuclear Waste ◽  
Magic Angle Spinning ◽  
Mas Nmr ◽  
Magic Angle ◽  
X Ray Diffraction ◽  
Crystalline Phases ◽  
X Ray ◽  
Mixed Alkali ◽  
Model Glass ◽  
Sodium Cesium

AbstractCrystalline precipitates from molybdenum-containing nuclear waste glasses are complex, often containing multiple cations which confound routine structural techniques. A simplified mixed-alkali borosilicate model glass was found to have minor crystalline phases which could not be identified by x-ray diffraction. Multinuclear magnetic resonance (NMR) spectroscopy revealed sharp peaks characteristic of crystallinity superimposed on the broader glass signals, but were unattributable to any known molybdate phases. When a comprehensive range of cesium molybdates failed to reveal any matches with the observed 133Cs magic-angle spinning (MAS) NMR peaks in the composite glass/crystalline material, a series of mixed-alkali sodium-cesium molybdate phases was synthesized. 23Na, 133Cs and 95Mo MAS NMR revealed the formation of two mixed-cation molybdates which correlate with the observed NMR peaks for the phase-separated model glass. This work highlights the prominence of multiple crystalline phases in Mo-bearing nuclear waste glasses, and demonstrates the unique utility of solid-state NMR as a fingerprinting approach to identifying complex phases, especially where x-ray diffraction is limited by multiple phases, low concentrations or substitutionally disordered precipitates.

scholarly journals Stoichiomorphic Halogen-Bonded Cocrystals. A Case Study of 1,4-Diiodotetrafluorobenzene and 3-Nitropyridine

2021 ◽  
Author(s):  
Christelle Hajjar ◽  
Tamali Nag ◽  
Hashim Al Sayed ◽  
Jeffrey S. Ovens ◽  
David L. Bryce
Keyword(s):  
Halogen Bond ◽  
Chemical Shifts ◽  
Magic Angle Spinning ◽  
Magic Angle ◽  
Halogen Bonds ◽  
X Ray Diffraction ◽  
Pyridyl Nitrogen ◽  
Space Group ◽  
X Ray ◽  
Variable Stoichiometry

The concept of variable stoichiometry cocrystallization is explored in halogen-bonded systems. Three novel cocrystals of 1,4-diiodotetrafluorobenzene and 3-nitropyridine with molar ratios of 1:1, 2:1, and 1:2, respectively, are prepared by slow evaporation methods. Single-crystal X-ray diffraction analysis reveals key differences between each of the nominally similar cocrystals. For instance, the 1:1 cocrystal crystallizes in the P21/n space group and features a single chemically and crystallographically unique halogen bond between iodine and the pyridyl nitrogen. The 2:1 cocrystal crystallizes in the P1- space group and features a halogen bond between iodine and one of the nitro oxygens in addition to an iodine-nitrogen halogen bond. The 1:2 cocrystal crystallizes with a large unit cell (V = 9896 Å3) in the Cc space group and features 10 crystallographically distinct iodine-nitrogen halogen bonds. Powder X-ray diffraction experiments carried out on the 1:1 and 2:1 cocrystals confirm that gentle grinding does not alter the crystal forms. 1H → 13C and 19F → 13C cross-polarization magic angle spinning (CP/MAS) NMR experiments performed on powdered samples of the 1:1 and 2:1 cocrystals are used as spectral editing tools to select for either the halogen bond acceptor or donor, respectively. Carbon-13 chemical shifts in the cocrystals are shown to change only very subtly relative to pure solid 1,4-diiodotetrafluorobenzene, but the shift of the carbon directly bonded to iodine nevertheless increases, consistent with halogen bond formation (e.g., a shift of +1.6 ppm for the 2:1 cocrystal). This work contributes new examples to the field of variable stoichiometry cocrystal engineering with halogen bonds.

Elucidation of correlated disorder in zeolite IM-18

2019 ◽  
Vol 75 (3) ◽  
pp. 333-342 ◽  
Author(s):  
Xiaoge Wang ◽  
Yihan Shen ◽  
Rongli Liu ◽  
Xiaolong Liu ◽  
Cong Lin ◽  
...  
Keyword(s):  
Single Crystal ◽  
Polycrystalline Sample ◽  
Simulation Method ◽  
Magic Angle Spinning ◽  
Two Dimensions ◽  
Mas Nmr ◽  
Double Quantum ◽  
Magic Angle ◽  
Disordered Structures ◽  
Angle Spinning

Classical crystallography is based on the translational periodicity of crystals and the analysis of discrete Bragg reflections. However, it is inadequate for determining disordered structures, of which the diffuse scattering is vital to evaluate the disorder level. The correlated disorder of IM-18 presents as zigzag chains arranged in translational periodicity and the double four-ring units randomly distributed along two dimensions. Supercell models regulated by multiple probabilities were systematically built to simulate the single-crystal and powder X-ray diffraction patterns in order to ascertain the specific disorder configuration in the single-crystal or polycrystalline samples of IM-18. The presence of defects in the polycrystalline sample was proved by combining 29Si magic angle spinning (MAS) NMR and 1H–1H double quantum MAS NMR spectra, and was quantitatively explored by the simulation method. The method could also elucidate other disordered structures in polycrystalline or single-crystal samples, despite the presence of defects or multidimensional disorder.

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