Search results for "METHANE"
showing 10 items of 1763 documents
Homoleptic Pnictogen-Chalcogen Coordination Complexes
2012
The synthesis and structural characterization of dicationic selenium and tellurium analogues of the carbodiphosphorane and triphosphenium families of compounds are reported. These complexes, [Ch(dppe)][OTf](2) [Ch = Se, Te; dppe = 1,2-bis(diphenylphosphino)ethane; OTf = trifluoromethanesulfonate], are formed using [Ch](2+) reagents via a ligand-exchange protocol and represent extremely rare examples of homoleptic pnictogen → chalcogen coordination complexes. The corresponding arsenic compounds were also prepared, [Ch(dpAse)][OTf](2) [Ch = Se, Te; dpAse = 1,2-bis(diphenylarsino)ethane], exhibiting the first instance of an arsenic → chalcogen dative bond. The electronic structures of these un…
Increased conformational rigidity of humic substances by oxidative biomimetic catalysis
2005
A synthetic water-soluble meso-tetra(2,6-dichloro-3-sulfonatophenyl)porphyrinate of iron(III) chloride, Fe(TDCPPS)Cl, was employed as a biomimetic catalyst in the oxidative coupling of terrestrial humic materials. High-performance size-exclusion chromatography (HPSEC), solid-state nuclear magnetic resonance (CPMAS-(13)C NMR), electron paramagnetic resonance (EPR), and diffuse reflectance infrared spectroscopy (DRIFT) were used to follow conformational and structural changes brought about in different humic materials by the oxidative coupling. Increase in apparent weight-average molecular weight (Mw(a)) occurred invariably for all humic substances with the oxidative polymerization catalyzed …
Multi-resolution investigations of the methane IR spectrum. At the borderline between modelling state of the art and astrophysical needs
2009
International audience; Remote sensing of the atmosphere of astrophysical objects relies essentially on molecular spectroscopy. Astrophysical investigations generally need both complete and accurate spectroscopic databases. Despite continuous efforts in experimental and theoretical spectroscopic investigations, the lack of data in specific spectral regions of interest is one of the principal limitation of the presently available spectroscopic databases. Extrapolations to relevant experimental conditions like high temperature is also a major issue for astrophysical applications. Among other molecules, methane is present in the atmosphere of many astrophysical objects. The modeling of its abs…
Crystal structure of diaqua[5,10,15,20-tetrakis(4-methoxyphenyl)porphyrinato-κ4N]iron(III) diaqua(18-crown-6)potassium bis(trifluoromethanesulfonate)…
2015
In the title compound, [FeIII(C48H36N4O2)(H2O)2][K(C12H24O6)(H2O)2](SO3CF3)2·2C12H24O6, the FeIIIatom is situated on an inversion centre and is octahedrally coordinated by four pyrrole N atoms of the deprotenated 5,10,15,20-tetrakis(4-methoxyphenyl)porphyrinate ligand and two water molecules. The average equatorial Fe—N(pyrrole) bond length [2.043 (6) Å] is consistent with a high-spin (S= 5/2) iron(III) metalloporphyrin derivative. The K+cation, which also lies on an inversion centre, is chelated by the six O atoms of one 18-crown-6 molecule and is additionally coordinated by two water molecules in a distorted hexagonal–bipyramidal geometry. In the crystal, the cations, anions and one non-c…
Crystal structure of bis-(azido-κN)bis[2,5-bis(pyridin-2-yl)-1,3,4-thia-diazole-κ(2) N (2),N (3)]cobalt(II).
2015
The structure of the title compound is isotypic with that of the analogous nickel(II) complex, in which the CoN6 core shows an axially weakly compressed octahedral geometry as opposed to the almost regular geometry exhibited by the NiN6 octahedron.
Dibromido[N-(1-diethylamino-1-oxo-3-phenylpropan-2-yl)-N′-(pyridin-2-yl)imidazol-2-ylidene]palladium(II) dichloromethane monosolvate
2019
In the molecule of the title N,N′-disubstituted imidazol-2-ylidene palladium(II) complex, [PdBr2(C21H24N4O)]·CH2Cl2, the palladium(II) atom adopts a slightly distorted square-planar coordination (r.m.s. deviation = 0.0145 Å), and the five-membered chelate ring is almost planar [maximum displacement = 0.015 (8) Å]. The molecular conformation is enforced by intramolecular C—H...Br hydrogen bonds. In the crystal, complex molecules and dichloromethane molecules are linked into a three-dimensional network by C—H...O and C—H...Br hydrogen bonds.
Tetrakis(dimethoxyboryl)methane
2016
The title compound, tetrakis(dimethoxyboryl)methane (systematic name: octamethyl methanetetrayltetraboronate), C9H24B4O8or C[B(OMe)2]4, is a useful synthetic intermediate. Crystals of this compound at 102 K conform to the orthorhombic space groupPbcn. The molecules, which reside on sites of crystallographic twofold symmetry, have idealized -4 point symmetry like most other CX4molecules in which eachXgroup bears two non-H substituents at the 1-position. The central C atom has a slightly distorted tetrahedral coordination geometry, with C—B bond lengths of 1.5876 (16) and 1.5905 (16) Å. One of the methoxy groups is disordered over two sets of sites; the major component has an occupancy factor…
CCDC 976053: Experimental Crystal Structure Determination
2015
Related Article: L. Ben Haj Hassen, Z. Denden, Y. Rousselin, H. Nasri|2015|Acta Crystallogr.,Sect.E:Cryst.Commun.|71|m215|doi:10.1107/S2056989015021039
An easy access to fused chromanones via rhodium catalyzed oxidative coupling of salicylaldehydes with heterobicyclic olefins
2016
Abstract Herein we describe a detailed study on the rhodium catalyzed oxidative coupling of salicylaldehydes with heterobicyclic olefins such as diazabicyclic olefins and urea-derived bicyclic olefins. The developed method provides an ideal route to fused chromanone systems in a single synthetic step. Moreover, the scope of this methodology was extended to different oxa/aza-bridged bicyclic urea derivatives.
CCDC 1434832: Experimental Crystal Structure Determination
2017
Related Article: A. Chernenkaya, A. Morherr, S. Backes, W. Popp, S. Witt, X. Kozina, S. A. Nepijko, M. Bolte, K. Medjanik, G. Öhrwall, C. Krellner, M. Baumgarten, H. J. Elmers, G. Schönhense, H. O. Jeschke, R. Valentí|2016|J.Chem.Phys.|145|034702|doi:10.1063/1.4958659