Search results for "phase"
showing 10 items of 6344 documents
Hydrogen bonding interaction of N5H with water: A first principle calculations
2019
Abstract The cyclopentazol (N5H) and its anion counterpart (N5–) have been studied extensively over the years and detected in the gas phase as well as in solution recently. In the present investigation, an attempt has been made to understand the interaction with water molecule using first principle calculations. Nature of interactions have been studied using both energy decomposition analysis and atoms in molecule (AIM) theory calculations. Further, the strength of non-covalent interactions were analysed using IGMplots.
A Ferroelectric Iron(II) Spin Crossover Material
2017
A dual-function material in which ferroelectricity and spin crossover coexist in the same temperature range has been obtained. Our synthetic strategy allows the construction of acentric crystal structures in a predictable way and is based on the high directionality of hydrogen bonds. The well-known iron(II) spin crossover complex [Fe(bpp)₂]²+ (bpp = 2,6-bis(pyrazol-3-yl)pyridine), a four-fold noncentrosymmetric H-bond donor, was combined with a disymmetric H-bond acceptor such as the isonicotinate (isonic) anion to afford [Fe(bpp)₂](isonic)₂·2H₂O. This low-spin iron(II) compound crystallises in the acentric nonpolar I-4 space group and shows piezoelectricity and SHG properties. Upon dehydra…
Hybrid Molecular Materials Based upon Magnetic Polyoxometalates and Organic π-Electron Donors: Syntheses, Structures, and Properties of Bis(ethylene…
1998
International audience; The syntheses, crystal structures, and physical properties of the series of radical salts made with bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF or ET) and monosubstituted α-Keggin polyoxoanions of formula [XZ(H2O)M11O39]5- (XZM11 = Si(IV)Fe(III)Mo11, Si(IV)Cr(III)W11, P(V)Con(II)W11, P(V)Ni(II)W11, P(V)Cu(II)W11 P(V)Zn(II)W11, P(V)Mn(II)W11, and P(V)Mn(II)Mo11) containing a magnetic metal ion Z on a peripheral octahedral site of the Keggin union are reported. They all crystallize in two related series called α2 and α3. The general structure consists of alternating layers of the organic donor and the Keggin polyoxometalates. While the stoichiometry and α-packing a…
Isomerisation of Liquid-Crystalline Tristriazolotriazines
2017
Star-shaped discotic liquid crystals with columnar superstructures constitute a highly interesting class of organic materials. Phenyl-substituted tris[1,2,4]triazolo-[1,3,5]triazine, prepared by a Huisgen reaction of phenyltetrazole and cyanuric chloride, represents an excellent core for discotic liquid crystals (DLCs). The thermal stability is not perfect, at temperatures above the clearing point, a successive threefold isomerization leads to a highly planar, C
Macrocyclic complexes based on [N⋯I⋯N]+ halogen bonds
2021
New 1–2 nm macrocyclic iodine(I) complexes prepared VIA a simple ligand exchange reaction manifest rigid 0.5–1 nm cavities that bind the hexafluorophosphate anion in the gas phase. The size of the cavities and the electrostatic interactions with the iodine(I) cations influence the anion binding properties of these macrocyclic complexes.
Encapsulation of tetramethylphosphonium cations
2009
International audience; The weak interactions and capsule formation of tetramethylphosphonium (TMP) cation with resorcinarenes 1 and 2 and the corresponding pyrogallarenes 3 and 4 were studied in the solid state by single crystal X-ray diffraction, in solution by NMR and in the gas phase by mass spectrometry. In methanol-D4, the NMR titration studies reveal that the association constants for the 1:1 complexes of TMP@3 and TMP@4 are much higher (TMP@4:390±37 M-1) than for the corresponding TMP@1 and TMP@2 (TMP@2:130±10 M-1) complexes. In the gas phase both monomeric 1:1 TMP@1-TMP@4 complexes as well as the dimeric 1:2 capsule complexes, TMP@12-TMP@42 were observed. The 1:1:2 molar mixtures o…
Analysis of psychoactive substances in water by information dependent acquisition on a hybrid quadrupole time-of-flight mass spectrometer.
2016
Emerging drugs of abuse, belonging to many different chemical classes, are attracting users with promises of “legal” highs and easy access via internet. Prevalence of their consumption and abuse through wastewater-based epidemiology can only be realized if a suitable analytical screening procedure exists to detect and quantify them in water. Solid-phase extraction and ultra-high performance liquid chromatography quadrupole time-of-flight-mass spectrometry (UHPLC–QqTOF–MS/MS) was applied for rapid suspect screening as well as for the quantitative determination of 42 illicit drugs and metabolites in water. Using this platform, we were able to identify amphetamines, tryptamines, piperazines, p…
Computational Study of the Effect of Glyoxal–Sulfate Clustering on the Henry’s Law Coefficient of Glyoxal
2014
We have used quantum chemical methods to investigate the molecular mechanism behind the recently reported ( Kampf , C. J. ; Environ. Sci. Technol . 2013 , 47 , 4236 - 4244 ) strong dependence of the Henry's law coefficient of glyoxal (C2O2H2) on the sulfate concentration of the aqueous phase. Although the glyoxal molecule interacts only weakly with sulfate, its hydrated forms (C2O3H4 and C2O4H6) form strong complexes with sulfate, displacing water molecules from the solvation shell and increasing the uptake of glyoxal into sulfate-containing aqueous solutions, including sulfate-containing aerosol particles. This promotes the participation of glyoxal in reactions leading to secondary organic…
A trajectory-based classification of ERA-Interim ice clouds in the region of the North Atlantic storm track
2016
A two-type classification of ice clouds (cirrus) is introduced, based on the liquid and ice water content, LWC and IWC, along air parcel backward trajectories from the clouds. In situ cirrus has no LWC along the trajectory segment containing IWC; it forms via nucleation from the gas phase. In contrast, liquid-origin cirrus has both LWC and IWC along their backward trajectories; it forms via lifting from the lower troposphere and freezing of mixed-phase clouds. This classification is applied to 12 years of ERA-Interim ice clouds in the North Atlantic region. Between 400 and 500 hPa more than 50% are liquid-origin cirrus, whereas this frequency decreases strongly with altitude (<10% at 200 hP…
An autonomous petrological database for geodynamic simulations of magmatic systems
2022
SUMMARY Self-consistent modelling of magmatic systems is challenging as the melt continuously changes its chemical composition upon crystallization, which may affect the mechanical behaviour of the system. Melt extraction and subsequent crystallization create new rocks while depleting the source region. As the chemistry of the source rocks changes locally due to melt extraction, new calculations of the stable phase assemblages are required to track the rock evolution and the accompanied change in density. As a consequence, a large number of isochemical sections of stable phase assemblages are required to study the evolution of magmatic systems in detail. As the state-of-the-art melting diag…