The Importance of Hydrogen Bonds for the Structure of Ionic Liquids: Single-Crystal X-ray Diffraction and Transmission and Attenuated Total Reflection Spectroscopy in the Terahertz Region

2010 ◽  
Vol 49 (52) ◽  
pp. 10221-10224 ◽  
Author(s):  
Christian Roth ◽  
Tim Peppel ◽  
Koichi Fumino ◽  
Martin Köckerling ◽  
Ralf Ludwig
Keyword(s):  
Ionic Liquids ◽  
Hydrogen Bonds ◽  
Single Crystal ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Reflection Spectroscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Terahertz Region

Thermal-induced transformation of glutamic acid to pyroglutamic acid and self-cocrystallization: a charge–density analysis

2022 ◽  
Vol 78 (2) ◽  
Author(s):  
Sehrish Akram ◽  
Arshad Mehmood ◽  
Sajida Noureen ◽  
Maqsood Ahmed
Keyword(s):  
Hydrogen Bonds ◽  
Glutamic Acid ◽  
Single Crystal ◽  
Diffraction Data ◽  
Density Functional ◽  
Quantitative Estimation ◽  
Topological Analysis ◽  
Pyroglutamic Acid ◽  
X Ray Diffraction ◽  
X Ray

Thermal-induced transformation of glutamic acid to pyroglutamic acid is well known. However, confusion remains over the exact temperature at which this happens. Moreover, no diffraction data are available to support the transition. In this article, we make a systematic investigation involving thermal analysis, hot-stage microscopy and single-crystal X-ray diffraction to study a one-pot thermal transition of glutamic acid to pyroglutamic acid and subsequent self-cocrystallization between the product (hydrated pyroglutamic acid) and the unreacted precursor (glutamic acid). The melt upon cooling gave a robust cocrystal, namely, glutamic acid–pyroglutamic acid–water (1/1/1), C5H7NO3·C5H9NO4·H2O, whose structure has been elucidated from single-crystal X-ray diffraction data collected at room temperature. A three-dimensional network of strong hydrogen bonds has been found. A Hirshfeld surface analysis was carried out to make a quantitative estimation of the intermolecular interactions. In order to gain insight into the strength and stability of the cocrystal, the transferability principle was utilized to make a topological analysis and to study the electron-density-derived properties. The transferred model has been found to be superior to the classical independent atom model (IAM). The experimental results have been compared with results from a multipolar refinement carried out using theoretical structure factors generated from density functional theory (DFT) calculations. Very strong classical hydrogen bonds drive the cocrystallization and lend stability to the resulting cocrystal. Important conclusions have been drawn about this transition.

Notizen: Solid State Structure of N,N-Dibenzylhydroxylamine

1995 ◽  
Vol 50 (4) ◽  
pp. 699-701 ◽  
Author(s):  
Norbert W. Mitzel ◽  
Jürgen Riede ◽  
Klaus Angermaier ◽  
Hubert Schmidbaur
Keyword(s):  
Solid State ◽  
Hydrogen Bonds ◽  
Single Crystal ◽  
Unit Cell ◽  
Monoclinic Space Group ◽  
State Structure ◽  
X Ray Diffraction ◽  
Space Group ◽  
Solid State Structure ◽  
X Ray

The solid-state structure of N,N-dibenzylhydroxylamine (1) has been determined by single crystal X-ray diffraction. The compound crystallizes in the monoclinic space group P 21/n with four formula units in the unit cell. N,N-dibenzylhydroxylamine dimerizes to give N2O2H2 sixmembered rings as a result of the formation of two hydrogen bonds O - H ··· N in the solid state.

Physicochemical Characteristics of an Ultra-Thin Hydrophobic Trichlorosilanes Using SiO2 as Adhesion

2019 ◽  
Vol 796 ◽  
pp. 80-87
Author(s):  
Akinsanya Damilare Baruwa ◽  
Esther Titilayo Akinlabi ◽  
Oluseyi Philip Oladijo ◽  
Stephen Akinwale Akinlabi ◽  
Jeff Chinn
Keyword(s):  
Room Temperature ◽  
Electrochemical Impedance ◽  
Physicochemical Characteristics ◽  
Total Reflection ◽  
Attenuated Total Reflection ◽  
Natural Seawater ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hydrophobic Silane ◽  
Better Than

The aim of the research is to subject the three different silanes to chemical and electrochemical investigations in other to determine the most efficient organic compound. Three types of hydrophobic silanes [Tris (Trimethylsiloxy) silyethyl] dimethylchlorosilane (Alkyl); Tridecafloro-1,1,2,2-tetrahydrooctyltrichlorosilane (FOTS) and Henicosyl-1,1,2,2-tetrahydrododecyltricholrosilane (FDDTS) are presented and investigated. The three silanes are of different composition but are deposited at the same parameters and conditions. The chemical investigation was studied through (attenuated total reflection Fourier-transform infrared (ATR-FTIR) and x-ray diffraction (XRD), while the electrochemical study was conducted through EIS using natural seawater electrolyte at room temperature. From the investigation techniques, only electrochemical impedance results show that FDDTS performed better than both Alkyl and FOTS. The chemical analysis showed the presence of hydrophobic silane on all the coated samples, and no distinction can be drawn from associated peaks.

scholarly journals High pressure studies of L-Serine-L-Ascorbic acid co-crystal

2014 ◽  
Vol 70 (a1) ◽  
pp. C988-C988
Author(s):  
Sergey Arkhipov ◽  
Boris Zakharov ◽  
Elena Boldyreva
Keyword(s):  
High Pressure ◽  
Ascorbic Acid ◽  
Hydrogen Bonds ◽  
Single Crystal ◽  
Crystal Engineering ◽  
Mixed Crystals ◽  
Study Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Wide Range

"Experiments for studying crystalline materials under extreme conditions are a powerful tool for investigating ""structure-property"" relationships. They also give information on the behavior of hydrogen bonds and are important both for materials science and crystal engineering. In addition, many processes in the living organisms are also related to mechanical stress. One of the most interesting tasks is to identify factors which influence the stability of a structure, or a part of the structure, at high pressure. Experiments on the systematic study of compounds in a wide range of pressures allow us to accumulate data that can be used to solve this problem. For a more complete picture, the mixed crystals of the selected compound are studied. Investigation of mixed crystals and cocrystals of interest can be compared with the crystals of individual compounds. We have chosen the structure of L-serine - L-ascorbic acid to be compared with those of L-serine and L-ascorbic acids for such a study. Phase transitions were previously reported to be induced by increasing pressure in both L-serine [1] and L-ascorbic acid [2]; moreover, the structure of L-serine was followed at multiple pressures by single-crystal and powder X-ray diffraction[3]. L-serine – L-ascorbic acid co-crystal was studied in the pressure range 0-5.4 GPa (at multiple points at every 0.5-0.7 GPa) by single-crystal X-ray diffraction and Raman spectroscopy. A phase transition has been detected and some rearrangement in the network of hydrogen bonds was observed. The high pressure data were compared with those for the individual structures of the L-serine and L-ascorbic acid. This work was supported by RFBR (grants 12–03-31541, 14-03-31866, 13-03-92704, 14-03-00902 ), Ministry of Science and Education of Russia and Russian Academy of Sciences."

Effect of pressure on crystalline L- and DL-serine: revisited by a combined single-crystal X-ray diffraction at a laboratory source and polarized Raman spectroscopy study

2012 ◽  
Vol 68 (3) ◽  
pp. 275-286 ◽  
Author(s):  
Boris A. Zakharov ◽  
Boris A. Kolesov ◽  
Elena V. Boldyreva
Keyword(s):  
Raman Spectroscopy ◽  
Hydrogen Bonds ◽  
Single Crystal ◽  
X Ray Diffraction ◽  
X Ray ◽  
Effect Of Pressure ◽  
Laboratory Source ◽  
Compression Mechanism ◽  
Polarized Raman Spectroscopy ◽  
Polarized Raman

Information on the effect of pressure on hydrogen bonds, which could be derived from single-crystal X-ray diffraction at a laboratory source and polarized Raman spectroscopy, has been compared. L-Serine and DL-serine were selected for this case study. The role of hydrogen bonds in pressure-induced phase transitions in the first system and in the structural stability of the second one are discussed. Non-monotonic distortion of selected hydrogen bonds in the pressure range below ∼ 1–2 GPa, a change in the compression mechanism at ∼ 2–3 GPa, and the evidence of formation of bifurcated N—H...O hydrogen bonds in DL-serine at ∼ 3–4 GPa are considered.

scholarly journals ISOLATION AND STRUCTURAL ELUCIDATION OF A NEW DEPSIDE OF LICHEN Everniopsis trulla

2021 ◽  
Vol 87 (2) ◽  
pp. 97-106
Author(s):  
Olivio Nino Castro ◽  
Jesús López Rodilla ◽  
Sofia Pombal ◽  
Francisca Sanz González ◽  
Julio Santiago Contreras
Keyword(s):  
Mass Spectrometry ◽  
Melting Point ◽  
Hydrogen Bonds ◽  
Single Crystal ◽  
Spectroscopic Data ◽  
Intermolecular Forces ◽  
X Ray Diffraction ◽  
Intermolecular Hydrogen Bonds ◽  
X Ray ◽  
Uv Visible

In this research, a new depside of the lichen Everniopsis trulla has been isolated. The extraction was carried out to 400 g of dry sample and ground with ethanol for 3 repetitions, then, it was fractionated by applying column chromatography with the CHCl3-MeOH system and purified by recrystallization with MeOH-Acetone (1: 1); Finally, white crystals in the form of needles (solid C) with a melting point of 198 ° C were obtained, whose structure was elucidated based on spectroscopic data (UV-Visible, IR, NMR-H1, NMR-C13, mass spectrometry and single crystal X-ray diffraction). According to the Science Finder databases, it is a new depside, called trullarin, and it is observed that molecular packing is influenced by both intramolecular and intermolecular forces. Intermolecular hydrogen bonds of O - H -O type binds neighboring molecules forming dimers.

scholarly journals Extraction and characterisation of cellulose nanocrystals (CNCs) from sugarcane bagasse using ionic liquids

2019 ◽  
Author(s):  
◽  
Gcinile Pretty Mdletshe
Keyword(s):  
Electron Microscopy ◽  
Ionic Liquids ◽  
Sugarcane Bagasse ◽  
Cellulose Nanocrystals ◽  
Crystallinity Index ◽  
Attenuated Total Reflection ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Pre Treatment

Lignocellulosic materials have the potential to partly replace fossil-based resources as a source of bio-fuels, bio-chemicals, bio-composites and other bio-products. In this study, ionic liquids (ILs) were used in the pre-treatment of ground sugarcane bagasse (SCB). The ILs used were 1-butyl-3-methylimidazolium hydrogen sulphate or 1-butyl-3-methylimidazolium methyl sulphate at varied times. The ILs were able to remove lignin and hemicellulose from biomass. The IL [bmim][HSO4] had the highest amount of lignin removed after 12 h than all samples. Moreover, it resulted in the greatest cellulose amount. Milled SCB was pre-treated with IL/dimethyl sulphoxide (DMSO) mixtures. The IL [bmim][HSO4] was able to produce cellulose nanocrystals (CNCs) at 90 % IL and 100 % IL. The other IL failed to produce CNCs. Freeze drying the CNC suspension showed morphologies of long fibrous structures and rods which were evident in the scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images. The crystallinity index of cellulose in the form of CNCs was calculated from powder X-ray diffraction (P-XRD). Thermal analysis of the CNCs was obtained from thermogravimetric analysis (TGA). Attenuated total reflection-Fourier transform infrared (ATR-FTIR) was used to confirm the absence of lignin and hemicellulose in CNCs. The size distribution of CNCs was obtained by using a dynamic light scattering (DLS) which showed that all the CNCs for the 100 % IL [bmim][HSO4] pre-treatment had a length < 500 nm. It was found that [bmim][HSO4], with no DMSO, was the most effective in terms of cellulose dissolution and the crystal sizes of CNCs. The conversion of cellulose to CNCs was successful with a 80 % and 100 % conversion for 90 % [bmim][HSO4]/DMSO and 100 % [bmim][HSO4], respectively.

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.

Synthesis and Characterization of the nido-Platinaborane 7,7-(PPh3)2-7-PtB10H11-11-OC(O)Me

2011 ◽  
Vol 66 (4) ◽  
pp. 387-391
Author(s):  
Jinling Miao ◽  
Yong Nie ◽  
Haiyan Chen ◽  
Daqi Wang ◽  
Markus Enders ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Hydrogen Bonds ◽  
Single Crystal ◽  
Elemental Analysis ◽  
Chain Structure ◽  
Synthesis And Characterization ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ir And Nmr Spectroscopy

The reaction of closo-B10H102− with PtCl2(PPh3)2 in the presence of MeCOSH afforded the title platinaborane nido-7,7-(PPh3)2-7-PtB10H11-11-OC(O)Me (1), which has been characterized by IR and NMR spectroscopy, MS, elemental analysis, and single-crystal X-ray diffraction. In contrast to the known products having exo-polyhedral Pt-S-C-O-B ring(s) from the same reaction with Ph- COSH, compound 1 has a B-acetoxy group on the open PtB4 face of the nido-PtB10 cluster. The structure of 1 features both intramolecular/intermolecular C-H· · ·O hydrogen bonds and intramolecular C-H· · ·H-B dihydrogen bonds, which link the molecules into a 1-D chain structure.

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