280 research outputs found
Reaction of diethyl vinylphosphonate with octyl- and dodecylamines
Diethyl vinylphosphonate reacted with octyl- and dodecylamines to give the corresponding addition products which underwent dealkylation via elimination of ethylene molecule with formation of crystalline zwitterionic ethyl 2-(alkylammonio)ethylphoshonates. © 2014 Pleiades Publishing, Ltd
Proposal for a Listening Comprehension Oriented Classroom -With focus on interpretation practise-
© 2016 American Chemical Society.Interaction of 4,5-dimethyl-2-(2-oxo-1,2-diphenyl)ethoxy-1,3,2-dioxaphospholane, bearing a carboxyl group in the γ-position with respect to the phosphorus atom and obtained from d,l-butanediol, with hexafluoroacetone (CCl4, -40 °C) leads to the simultaneous formation of regio- and stereoisomeric cage-like phosphoranes with phosphorus-carbon and phosphorus-oxygen bonds with a high stereoselectivity (>95%), whose structure was determined by 1D and 2D NMR spectroscopy and XRD. When stored as a solution in dichloromethane for one month, the PCO-isomer rearranges into the thermodynamically more stable POC-isomer of the cage-like phosphorane. Mild hydrolysis of the PCO/POC-isomers proceeds with a high chemoselectivity and leads to the formation of P(IV)-dioxaphospholane derivatives. Acidic hydrolysis of the POC-isomer leads to the formation of an oxirane derivative with an unexpectedly high stereoselectivity (>95%). DFT calculations (using the PBE functional) allowed us to obtain structures and energies of the initial phospholane, reaction products (PCO/POC-isomers), and an intermediate P(V)-oxaphosphirane
1,10-diaza-18-crown-ether, modified by phosphonate pendant arms - Synthesis, structure, and picrate extraction properties
Reaction of O,O′-diisopropyl-3-methyl-1,2-butadienylphosphonate with 1,10-diaza-18-crown-6 in the presence of a catalytic amount of iPrONa leads to the new crown-ether derivative, containing phosphonate pendant arms (L). The structure of the compound obtained was investigated by single crystal X-ray diffraction analysis, IR, 1H and 31P{1H} NMR spectroscopy, and microanalysis. In the crystal structure the side arms of L are in an anti disposition relative to the macrocyclic cavity. It was established that phosphorylation of 1,10-diaza-18-crown-6 by allenylphosphonate results in an increase of extraction of NaPic and KPic, whereas LiPic and NH4Pic are extracted practically in the same level. © 2008 Wiley-VCH Verlag GmbH & Co. KGaA
Reaction of N-diisopropoxyphosphorylthiobenzamide (HL) with the Co II cation: The crystal structure of CoL2 and CoL 2·2HL complexes
The title complexes CoL2 and CoL2·2HL were synthesised and characterised using IR spectroscopy, mass spectrometry and single-crystal X-ray diffraction analysis
A numerical and symbolical approximation of the Nonlinear Anderson Model
A modified perturbation theory in the strength of the nonlinear term is used
to solve the Nonlinear Schroedinger Equation with a random potential. It is
demonstrated that in some cases it is more efficient than other methods.
Moreover we obtain error estimates. This approach can be useful for the
solution of other nonlinear differential equations of physical relevance.Comment: 21 pages and 7 figure
The Nonlinear Schroedinger Equation with a random potential: Results and Puzzles
The Nonlinear Schroedinger Equation (NLSE) with a random potential is
motivated by experiments in optics and in atom optics and is a paradigm for the
competition between the randomness and nonlinearity. The analysis of the NLSE
with a random (Anderson like) potential has been done at various levels of
control: numerical, analytical and rigorous. Yet, this model equation presents
us with a highly inconclusive and often contradictory picture. We will describe
the main recent results obtained in this field and propose a list of specific
problems to focus on, that we hope will enable to resolve these outstanding
questions.Comment: 21 pages, 4 figure
N-thiophosphorylthiourea containing an aza-18-crown-6 fragment. The crystal structure of bis [N-(N′-diisopropoxythiophosphorylamidothiocarbonyl)- aza-18-crown-6]nickel(II)
N-(N′-Diisopropoxythiophosphorylamidothiocarbonyl)aza-18-crown-6 (HL) was obtained by the reaction of aza-18-crown-6 with diisopropoxythiophosphorylisothiocyanate, and its chelate with NiII was characterised using IR, 1H and 31P NMR spectroscopy and single-crystal X-ray diffraction
Synthesis, crystal structure and hydrolysis of novel isomeric cage (P-C/P-O)-phosphoranes on the basis of 4,4,5,5-tetramethyl-2-(2-oxo-1,2-diphenylethoxy)-1,3,2-dioxaphospholane and hexafluoroacetone
© The Royal Society of Chemistry 2016.The reaction of 4,4,5,5-tetramethyl-2-(2-oxo-1,2-diphenylethoxy)-1,3,2-dioxaphospholane with hexafluoroacetone leads to the simultaneous formation of regioisomeric cage (P-C/P-O)-phosphoranes, the structures of which are unequivocally confirmed by XRD. The rearrangement of the P-C-isomer to P-O-isomer with high stereoselectivity (>96%) takes place in methylene chloride solution with the retention of the phosphorus coordination. It was found that the stepwise hydrolysis of the P-O-isomer initially gives 2-(2,3-dihydroxy-1,2-diphenyl-3-trifluoromethyl-4,4,4-trifluorobutyloxy)-4,4,5,5-tetramethyl-2-oxo-1,3,2-dioxaphospholane as the only stereoisomer whose structure is also confirmed by XRD. Further hydrolysis of this compound leads to the formation of 2,3-dihydroxy-3-trifluoromethyl-4,4,4-trifluoro-1,2-diphenylbutylphosphate and pinacol, which forms the solvate in the crystal. Hydrolysis of the P-C-isomer yields 2-hydroxy-4,4,5,5-tetramethyl-2-oxo-1,3,2-dioxaphospholane, benzoin and hexafluoroisopropanol
Reaction of diethyl 3-methyl-1,2-butadienylphosphonate with 1,10-diaza-18-crown-6
Reaction of two-fold excess of diethyl 3-methyl-1,2-butadienylphosphonate with 1,10-diaza-18- crown-6 leads to the formation of an adduct whose molecule includes two 1-phosphoryl-3-methyl-2-butene fragments bound together by a crown bridge with the anti location of organophosphorus groups relative to the macrocycle plane. The 1,2-multiple bond of the phosphonate is involved in the reaction. Extraction properties of the diphosphorylated crown ether toward alkali metal picrates were studied. © Pleiades Publishing, Ltd., 2009
Synthesis and structure of novel substituted N-sulfinylanilines
© 2017, Pleiades Publishing, Ltd. N-Sulfinylanilines derived from 4-bromoaniline, 3-nitroaniline, and 4,4′-di(ethane-1,2-diyl)dianiline were synthesized. X-ray diffraction analysis of 4-bromo-N-sulfinylaniline, 3-nitro-N-sulfinylaniline, and 4,4′-(ethane-1,2-diyl)di-N-sulfinylaniline was performed. The sulfinyl function in the planar conformation of the Ar-NSO fragment was found to have Z configuration. The nature of intra- and intermolecular structure-forming interactions was established
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