Beiträge zur Chemie des Phosphors, 234 [1,2] Lithium-tetrahydrogencyclopentaphosphid: Synthese, Struktur und Reaktionen / Contributions to the Chemistry of Phosphorus, 234 [1,2] Lithium Tetrahydrogen Cyclopentaphosphide: Synthesis, Structure and Reactions

1995 ◽  
Vol 50 (5) ◽  
pp. 786-790 ◽  
Author(s):  
Marianne Baudler ◽  
Rudolf Heumüller ◽  
Wolfgang Faber
Keyword(s):  
Low Temperature ◽  
Complete Analysis ◽  
Lemon Yellow ◽  
Compound I ◽  
Polar Solvents ◽  
Open Chain ◽  
Nmr Spectrum ◽  
H Nmr ◽  
Nmr Parameters ◽  
Reaction Compound

Abstract Lithium tetrahydrogen cyclopentaphosphide. LiH4P5 (I). has been obtained by metalation of P2H4 at -78 °C with either n-BuLi or LiPH2 in polar solvents. Upon suitable performance of the reaction, compound I can be isolated at low temperature as a lemon-yellow solvent adduct. The structure as the monolithium salt of (PH)5 was confirmed by a complete analysis of the 31P{1H}-NMR spectrum. On warming above -35 °C, disproportionation occurs yield­ing Li2HP7. P2H4. and PH3. The reaction with n-BuLi produces the open-chain phosphides LiH4P3. LiH3P2, and LiPH2. The NMR parameters of LiH3P2 and LiH4P3 are reported. Reac­tion of 1 with P2H4 gives rise to the bicyclic and polycyclic phosphides LiH4P7, LiH5P8 and Li2H2P14, respectively.

21,22-Disubstituted 18α,19βH-Ursane Derivatives with Oxabicyclooctane System in Ring E

1993 ◽  
Vol 58 (1) ◽  
pp. 173-190 ◽  
Author(s):  
Eva Klinotová ◽  
Jiří Klinot ◽  
Václav Křeček ◽  
Miloš Buděšínský ◽  
Bohumil Máca
Keyword(s):  
Spectral Data ◽  
Spin Systems ◽  
Coupling Constants ◽  
Complete Analysis ◽  
Nmr Spectrum ◽  
Proton Proton ◽  
H Nmr ◽  
Proton Coupling ◽  
C Nmr

Reaction of 3β-acetoxy-21,22-dioxo-18α,19βH-ursan-28,20β-olide (IIIa) and 20β,28-epoxy-21,22-dioxo-19α,19βH-ursan-3β-yl acetate (IIIb) with diazomethane afforded derivatives XII-XIV with spiroepoxide group in position 21 or 22, which were further converted into hydroxy derivatives XV and XVII. Ethylene ketals VIII-X were also prepared. In connection with the determination of position and configuration of the functional groups at C(21) and C(22), the 1H and 13C NMR spectral data of the prepared compounds are discussed. Complete analysis of two four-spin systems in the 1H NMR spectrum of bisethylenedioxy derivative Xb led to the proton-proton coupling constants from which the structure with two 1,4-dioxane rings condensed with ring E, and their conformation, was derived.

scholarly journals Beiträge zur Chemie des Phosphors, 204. Zur Existenz eines Triphosphacyclobutenid-Ions P3CH2Ɵ / Contributions to the Chemistry of Phosphorus, 204. On the Existence of a Triphosphacyclobutenide Ion P3CH2e

1990 ◽  
Vol 45 (8) ◽  
pp. 1139-1142 ◽  
Author(s):  
Marianne Baudler ◽  
Josef Hahn
Keyword(s):  
White Phosphorus ◽  
Complete Analysis ◽  
Nmr Spectrum ◽  
H Nmr ◽  
Low Field

The structure of the reaction product of white phosphorus and sodium in diglyme which exhibits a low field AB2 system in the 31P{1H} NMR spectrum [4] has been reexamined. According to the results of a complete analysis of its proton coupled 31P NMR spectrum (ABB′XX′ system), the compound is the hitherto unknown 1,2,3-triphosphacyclopentadienide ion P3(CH)2⊖ (4), and not the triphosphacyclobutenide ion P3CH2⊖(3) previously assumed [4]. The parameters of the Ρ,Η-coupled 31P NMR spectrum of the tetraphosphacyclopentadienide ion P4CH⊖ (2) have also been calculated.

Complete analysis of the 1H nmr spectrum of tetrahydrothiophene

1980 ◽  
Vol 58 (22) ◽  
pp. 2340-2348 ◽  
Author(s):  
Angel Luis Esteban ◽  
Ernesto Díez
Keyword(s):  
Potential Energy ◽  
1H Nmr ◽  
Time Scale ◽  
Complete Analysis ◽  
Nmr Spectrum ◽  
H Nmr ◽  
Karplus Relationship ◽  
The One

The 1H nmr spectrum of tetrahydrothiophene has been analyzed. The best set of coupling values (Hz) is: [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text] (A and B refer to α-and β-protons and c and t denote respectively the same and opposite sides of the ring). The variances observed between the values of this set and those reported by Lozach etal., particularly the interchange of the [Formula: see text] and [Formula: see text] couplings, are discussed and it is concluded that our set is the one that reproduces the most fine details of the spectrum profile. The proposed set has been selected as being the most physically meaningful, from amongst 24 equally valid sets of couplings, on the basis of a better agreement with the [Formula: see text] and [Formula: see text] values calculated from a Karplus relationship and from the INDO-FPT method respectively. In these calculations it was assumed that the molecule was interconverting rapidly (on the nmr time scale) between two puckered conformations with C2 symmetry. A detailed discussion of the dependence of the couplings on the height of the pseudorotational barrier and on the temperature indicate that the minimum values of the potential energy correspond to these conformations.

PhAs(C5H4)2TiCl2: Das erste Arsen-überbrückte Titanocenophan / PhAs(C5H4)2TiCl2: The First Arsenic-Bridged Titanocenophane

1991 ◽  
Vol 46 (5) ◽  
pp. 647-649 ◽  
Author(s):  
Nikolaos Klouras
Keyword(s):  
Low Temperature ◽  
Nmr Spectrum ◽  
Stable Compound ◽  
H Nmr ◽  
Temperature Conditions

By reacting PhAsCl2 with NaC5H5 in toluene under low temperature conditions PhAs(h1-C5H5)2 was obtained. Metallation of PhAs(h1-C5H5)2 with n-BuLi followed by reaction with TiCl4 led to the As-bridged [1]titanocenophane. The structure and conformation of this air-stable compound are discussed in the light of its 1H NMR spectrum.

Beiträge zur Chemie des Phosphors, 147 [1] 31P-Kernresonanzspektrum und Struktur von Hexaethyl-octaphosphan(6), P8Et6 / Contributions to the Chemistry of Phosphorus, 147 [1] 31P NMR Spectrum and Structure of Hexaethyloctaphosphane(6), P8Et6

1984 ◽  
Vol 39 (12) ◽  
pp. 1671-1675 ◽  
Author(s):  
Marianne Bäudler ◽  
Eberhard Därr ◽  
Gerhard Binsch ◽  
David S. Stephenson
Keyword(s):  
31P Nmr ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Complete Analysis ◽  
Nmr Spectrum ◽  
H Nmr ◽  
Configuration And Conformation

Hexaethyloctaphosphane(6) (1) was proven to possess the structure of a 2,3,4,6,7,8-hexaethylbicyclo[3.3.0]octaphosphane by a complete analysis of its 31P {1H } NMR spectrum. The chemical shifts and coupling constants yielded inform ation about the configuration and conformation of 1.

scholarly journals Beiträge zur Chemie des Phosphors, 132 [1]. 31P-Kernresonanzspektrum und Struktur von Trimethylheptaphosphan(3), P7Me3 / Contributions to the Chemistry of Phosphorus, 132 [1]. 31P NMR Spectrum and Structure of Trimethylheptaphosphane(3), P7Me3

1983 ◽  
Vol 38 (8) ◽  
pp. 955-960 ◽  
Author(s):  
Marianne Bäudler ◽  
Thomas Pontzen
Keyword(s):  
31P Nmr ◽  
Chemical Shifts ◽  
Experimental Spectrum ◽  
Complete Analysis ◽  
Methyl Groups ◽  
Nmr Spectrum ◽  
H Nmr

Trimethylheptaphosphane(3) (1) was proved to possess the earlier reported structure of a 3,5,7-triorganotrieyclo[2.2.1.02,6] heptaphosphane [3] by complete analysis of its 31P{1H} NMR spectrum. The experimental spectrum can be simulated very satisfactorily by the superposition of the spectra of two isomers P7Me3sym and P7Me3 asym, differing from each other in the orientation of the methyl groups. A comparison of the chemical shifts with those of (Me3Si)3P7 and Li3P7 leads to a detailed information about the geometry of the P7-skeleton in both isomers of 1.

Some unique properties of in 2-fluorotoluene derivatives. Conformational dependence

1983 ◽  
Vol 61 (1) ◽  
pp. 29-36 ◽  
Author(s):  
Ted Schaefer ◽  
Rudy Sebastian ◽  
Richard P. Veregin ◽  
Reino Laatikainen
Keyword(s):  
Strong Dependence ◽  
Spin Coupling ◽  
Complete Analysis ◽  
Matrix Elements ◽  
Coupling Constant ◽  
Nmr Spectrum ◽  
H Nmr ◽  
Spin Spin Coupling ◽  
Coupling Mechanisms ◽  
Derivatives Of

A complete analysis of the 1H nmr spectrum of 2-fluorotoluene yields [Formula: see text] the spin–spin coupling constant between 19F and the methyl protons, as 1.99 Hz. Analysis of nmr spectra of 21 other derivatives of 2-fluorotoluene shows that [Formula: see text] can vary between 1.69 and 2.55 Hz. This strong dependence on substitution contrasts with the near invariance of other long-range couplings such as [Formula: see text], [Formula: see text], [Formula: see text] The substituent dependence is discussed in terms of coupling mechanisms. INDO MO FPT calculations of [Formula: see text] are inadequate. By means of appropriate model compounds, an adequate empirical conformational dependence is deduced for [Formula: see text] which can be used to reproduce some observed couplings. INDO MO FPT computations, in which certain off-diagonal Fock matrix elements are suppressed, are used to show that spin polarization via interacton of the methyl hydrogen orbitals is a major source of the discrepancy between theory and experiment. Some STO 3G MO calculations are reported for 2-fluorotoluene conformations.

Beiträge zur Chemie des Phosphors, 161 [1] Kernresonanzspektren und Struktur von Heptaphosphan(3), P7H3 / Contributions to the Chemistry of Phosphorus, 161 [1] NMR Spectra and Structure of Heptaphosphane(3), P7H3

1985 ◽  
Vol 40 (11) ◽  
pp. 1424-1429 ◽  
Author(s):  
Marianne Bäudler ◽  
Renate Riekehof-Böhmer
Keyword(s):  
Nmr Spectra ◽  
Chemical Shifts ◽  
Spatial Arrangement ◽  
Complete Analysis ◽  
Hydrogen Atoms ◽  
Nmr Spectrum ◽  
H Nmr

Heptaphosphane(3) (1) is obtained pure by the reaction of (Me3Si)3P7 with methanol and has been characterized NMR spectroscopically (in nascent state). It turned out to be a mixture of two diastereomers P7H3sym and P7H3asym, which differ in the spatial arrangement of the hydrogen atoms. Both isomers were proven to possess the earlier reported structure of a tri-cyclo[2.2.1.02,6]heptaphosphane, which in the case of P7H3sym was ascertained by a complete analysis of its 31P{1H} NMR spectrum. As shown by the chemical shifts, the P7 cage in P7H3sym is clearly stretched compared with P7Me3sym and (Me3Si)3P7.

The structure of yatein. Determination of the positions, and configurations of benzyl groups in lignans of the 2,3-dibenzylbutyrolactone type

1982 ◽  
Vol 47 (2) ◽  
pp. 644-663 ◽  
Author(s):  
Juraj Harmatha ◽  
Miloš Buděšínský ◽  
Antonín Trka
Keyword(s):  
Absolute Configuration ◽  
Nmr Spectra ◽  
Optical Rotation ◽  
Shift Reagent ◽  
Complete Analysis ◽  
Nmr Spectrum ◽  
H Nmr ◽  
Determination Of Absolute Configuration ◽  
Erroneous Interpretation

The structure of yatein isolated from Libocedrus yateensis has been determined as (2R, 3R)-2-(3,4,5-trimethoxybenzyl)3-(3,4-methylenedioxybenzyl)butyrolactone (Ia). The assignment of individual signals of the 1H NMR spectrum of yatein and further lignans of the 2,3-dibenzyl-butyrolactone type is discussed and supported by the use of a lanthanide shift reagent and by mass spectrometry of deuterated derivatives IIa, IIb. A method of determination of absolute configuration of the centres C(2) and C(3) of these 2,3-dibenzylbutyrolactone lignans on the basis of a combination of information obtained from 1H NMR spectra and optical rotation is proposed. The erroneous interpretation of the ORD and CD spectra used in some instances for the determination of absolute configuration of these substances, as well as the often repeated error in the assignment of benzyl and C(2)-H, C(3)-H protons in 1H NMR spectra of trans-lignans is also discussed. A complete analysis of the 1H NMR spectra permitted the proposition of the preferred conformation for trans and cis isomer Ia and Ib.

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