13C and 119Sn NMR spectra of diphenyl- and dibenzyltin(IV) compounds and their complexes

1990 ◽  
Vol 55 (5) ◽  
pp. 1193-1207 ◽  
Author(s):  
Jaroslav Holeček ◽  
Antonín Lyčka ◽  
Karel Handlíř ◽  
Milan Nádvorník
Keyword(s):  
Internal Structure ◽  
Coordination Sphere ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Spectral Parameters ◽  
The Real ◽  
119Sn Nmr ◽  
C Nmr

13C and 119Sn NMR spectra of diphenyl- and dibenzyltin(IV) compounds have been studied in solutions of coordinating and non-coordinating solvents. Regions of values of the δ(119Sn) chemical shifts have been determined which characterize individual types of coordination of the central tin atom. The values of 13C NMR spectral parameters, the δ(13C) chemical shifts and nJ(119Sn, 13C) coupling constants, have been used to describe the real shapes of coordination sphere of the central tin atom and to discuss the internal structure of the organic substituents and of the nature of their bonding linkage to the tin atom.

Carbon-13 and nitrogen-14 NMR spectra of 1-(substituted phenyl)pyridinium salts

1980 ◽  
Vol 45 (10) ◽  
pp. 2766-2771 ◽  
Author(s):  
Antonín Lyčka
Keyword(s):  
Heavy Water ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Pyridinium Salts ◽  
Nmr Signals ◽  
C Nmr

The 13C and 14N NMR spectra of 1M solutions of 1-(substituted phenyl)pyridinium salts (4-CH3, 4-OCH3, H, 4-Cl, 4-Br, 4-I, 3-NO2, 4-NO2, 2,4-(NO2)2 (the 13C NMR only)) have been measured in heavy water at 30 °C. The 13C and 14N chemical shifts, the 1J(CH) coupling constants, some 3J(CH) coupling constants, and values of half-widths Δ 1/2 of the 14N NMR signals are given. The 13C chemical shifts of C(4) correlate with the σ0 constants (δC(4) = (1.79 ± 0.097) σ0 + (147.67 ± 0.041)), whereas no correlation of the nitrogen chemical shifts with the σ constants has been found. The half-widths Δ 1/2 correlate with the σ0 constants (Δ 1/2 = (76.2 ± 4.9) σ0 + (106.4 ± 2.2)) except for 1-phenylpyridinium chloride.

Phosphinsubstituierte Chelatliganden, XXIII [1] Darstellung und NMR-Spektren von Alkyl-arylphosphinothioformamiden, R(Ph)PC(S)NHMe / Phosphine-Substituted Chelate Ligands, XXIII [1] Synthesis and NMR Spectra of Alkyl-arylphosphinothioformamides, R(Ph)PC(S)NHMe

1987 ◽  
Vol 42 (1) ◽  
pp. 77-83 ◽  
Author(s):  
Udo Kunze ◽  
Rolf Tittmann
Keyword(s):  
Chemical Shift ◽  
Linear Correlation ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Cone Angle ◽  
Coupling Constants ◽  
Methyl Isothiocyanate ◽  
Signal Sets ◽  
The Asymmetry ◽  
C Nmr

Abstract A series of alkyl-arylsubstituted N-methyl phosphinothioformamides, R(Ph)PC(S)NHMe (2 a-g), with varying bulkiness of the alkyl rest was synthesized from the racemic secondary phosphines 1a-g and methyl isothiocyanate. 1H and 13C NMR spectra of 2a−g reveal signal sets of diastereotopic nuclei due to the asymmetry of the molecule. The chemical shift and coupling constants were confirmed by simulation in case of 2b, c. The vicinal 31P−13C couplings of the menthyl and neomenthyl compounds 2f, g show an "anti-Karplus" behaviour (3J(gauche) > 3J(trans)) and allow the conformational assignment of the alicyclic group. The 31P chemical shifts of 2a−d give a linear correlation with the cone angle of the alkyl substituents quoted from literature.

scholarly journals Carbon-13 nuclear magnetic resonance spectra of oxazoles

1979 ◽  
Vol 57 (23) ◽  
pp. 3168-3170 ◽  
Author(s):  
Henk Hiemstra ◽  
Hendrik A. Houwing ◽  
Okko Possel ◽  
Albert M. van Leusen
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Proton Coupling ◽  
Nuclear Magnetic Resonance Spectra ◽  
C Nmr ◽  
Magnetic Resonance Spectra ◽  
Nuclear Magnetic

The 13C nmr spectra of oxazole and eight mono- and disubstituted derivatives have been analyzed with regard to the chemical shifts and the various carbon–proton coupling constants of the ring carbons. The data of the parent oxazole are compared with thiazole and 1-methylimidazole.

29Si, 13C and 31P NMR spectra of silicon-substituted ω-diphenylphosphinoalkyl silanes, (CH3)3-n(OC2H5)nSi(CH2)mP(C6H5)2

1982 ◽  
Vol 47 (3) ◽  
pp. 793-801 ◽  
Author(s):  
Jan Schraml ◽  
Martin Čapka ◽  
Harald Jancke
Keyword(s):  
Nmr Spectra ◽  
31P Nmr ◽  
Chemical Shifts ◽  
Additivity Rule ◽  
Ethoxy Group ◽  
Spectral Parameters ◽  
Nmr Spectrum ◽  
Nmr Parameters ◽  
13C And 31P Nmr ◽  
C Nmr

29Si, 13C, and 31P NMR spectra of a series of compounds of the structure (CH3)3-n(C2H5O)n.Si(CH2)mP(C6H5)2 (m = 1-6, n = )-3) are reported and assigned. Using monodeutero derivative of the compound with m = 3 and n = 0 an earlier assignment of 13C NMR spectrum is confirmed, but the assignment in the compounds with m = 4 is reversed. Introduction of ethoxy groups leads to violation of additivity rule for the 13C chemical shifts in the derivatives with m = 1. In all derivatives presence of one ethoxy group in the molecule has a profound effect on 31P chemical shift which is not changed by any further increase in the number of ethoxy groups in the molecule. The changes in 29Si chemical shifts follow the pattern known from other series of compounds. The observed trends in NMR parameters with changing n and m values can be explained by an interaction between phosphorus and oxygen atoms. Possible connections between the spectral parameters and catalysis employing the studied compounds are discussed.

Structural revision of glabramycins B and C, antibiotics from the fungus Neosartorya glabra by DFT calculations of NMR chemical shifts and coupling constants

RSC Advances ◽  
2015 ◽  
Vol 5 (46) ◽  
pp. 36858-36864 ◽  
Author(s):  
Yang Li
Keyword(s):  
Natural Products ◽  
Dft Calculations ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Proton Proton ◽  
Structural Revision ◽  
Proton Coupling ◽  
Vicinal Proton ◽  
C Nmr

The 13C NMR spectra and vicinal proton–proton coupling constants of two tricyclic macrolactone natural products were analyzed using computational methods, which resulted in their structural revisions.

Molecular Determinants for Drug-Receptor Interactions. 6. Proton 500 MHz NMR Spectra of the Narcotic Antagonists Naloxone and Naltrexone by Two-Dimensional 1H–1H Chemical Shift Correlation Spectroscopy

1986 ◽  
Vol 41 (2) ◽  
pp. 231-238 ◽  
Author(s):  
Bruno Perly ◽  
Giuseppe C. Pappalardo ◽  
Antonio Grassi
Keyword(s):  
Nmr Spectra ◽  
Chemical Shifts ◽  
Relaxation Times ◽  
Chair Conformation ◽  
Correlation Spectroscopy ◽  
Coupling Constants ◽  
Piperidine Ring ◽  
Two Dimensional ◽  
Spectral Parameters ◽  
Narcotic Antagonists

The full analysis of the 1H NMR spectra of naloxone and naltrexone (hydrochloride salts, in 2H2O solution) was performed by using an high-frequency (500 MHz) spectrometer and the recent technique of two-dimensional (2D ) homonuclear shift spectroscopy. The 1H-1H connectivities allowed detection of correlated resonances and assignments of multiplets. The shapes of the contour levels of the COSY 45 spectra were also used to check the relative signs of coupling constants. The refinement of spectral parameters of some component spin-systems of the complex spectra was performed by computerized iterative simulation of patterns.The spectral analysis provided proton coupling constants that allowed to establish a slightly distorted-chair conformation of the piperidine ring in both compounds.The magnetic non-equivalence found for the protons bonded to C-17 atom (part of the N-alkyl fragment) was found to be larger in naltrexone than in the analogous naloxone. This fact, while no significant differences were observable in the chemical shifts of corresponding protons of the rigid molecular backbone of the two narcotic antagonists under study, was assigned to smaller degree of internal conformational flexibility of the N-methylcyclopropyl group in naltrexone with respect to that of the N-methylallyl group in naloxone.The above findings appeared in good agreement with our previously proposed views based on results from 13C relaxation times studies, which suggested the possible correlation of the motional rates of the N-methyl-R group to the pharmacological activity of antagonist compounds. This would consist in a direct correlation between decreasing flexibility of the N-bonded fragment and increasing antagonistic potency.

NMR-spektroskopische Untersuchung des Problems der Valenzisomerie zwischen 1,2-Dithiin und (Z)-But-2-en-1,4-dithion / NMR Spectroscopic Investigation Concerning the Problem of Valence Isomerism between 1,2-Dithiine and (Z)-But-2-ene-1,4-dithione

1988 ◽  
Vol 43 (5) ◽  
pp. 605-610 ◽  
Author(s):  
Reiner Radeglia ◽  
Helmut Poleschner ◽  
Werner Schroth
Keyword(s):  
Nmr Spectra ◽  
Chemical Shifts ◽  
2D Nmr ◽  
Ring Structure ◽  
Coupling Constants ◽  
Nmr Parameters ◽  
Spectrum Simulation ◽  
2D Nmr Spectra ◽  
Transoid Conformation ◽  
C Nmr

3,6-Diaryl-1,2-dithiines and their precursors, (Z,Z)-1,4-bis(organylthio)-buta-1,3-dienes, are investigated by 1H and 13C NMR spectroscopy. The chemical shifts and coupling constants, which are relevant to the investigated problem, are determined and assigned, respectively, by different techniques (shift increments, spectrum simulation, heteronuclear 2D J-resolved and heteronuclear shift correlated 2D NMR spectra, anomalous off-resonance splittings and selective decoupling experiments). The NMR parameters are discussed in relation to the molecular structure. The 13C shift values prove the ring structure of 1,2-dithiines and exclude existence of the valence isomer (Z)-but-2-ene-1,4-dithione (absence of thiocarbonyl resonances). The vicinal 1H,1H coupling constants of the C4 unit of the investigated compounds verify (1) the (Z,Z) configuration of the organylthio groups in 1,4 position of butadiene, (2) the s-transoid conformation of acyclic butadienes and (3) the forced s-cis structure in the cyclic 1,2-dithiines.

13C and 1H NMR spectra of all methyl O-benzoyl-β-D-xylopyranosides. nonadditivity of acylation effects on 13C chemical shifts in deutoriochloroform solutions

1983 ◽  
Vol 48 (3) ◽  
pp. 877-888 ◽  
Author(s):  
Eva Petráková ◽  
Jan Schraml
Keyword(s):  
1H Nmr ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Conformational Heterogeneity ◽  
Additivity Rule ◽  
Homonuclear Decoupling ◽  
First Order ◽  
H Nmr ◽  
C Nmr

All methyl O-benzoyl-β-D-xylopyranosides have been prepared and their 1H and 13C NMR spectra measured in deuteriochloroform solutions. The 1H NMR spectra were analysed to the first order and assigned with the aid of homonuclear decoupling. The 13C chemical shifts were assigned through heteronuclear selective decouling experiments. Some of the 13C chemical shifts observed in di- and tri-O-benzoyl derivatives differ considerably from those calculated according to the direct additivity rule from the shifts in the mono derivatives. It is shown that the nonadditivity is due to a conformational heterogeneity of the series of investigated compounds dissolved in deuteriochloroform. The heterogeneity is evidenced by the vicinal 1H-1H coupling constants and by 13 chemical shifts of C(1) methoxyl carbon atoms.

13C and 15N NMR spectra of oximes prepared by nitrosation of activated methylene group

1990 ◽  
Vol 55 (1) ◽  
pp. 136-146 ◽  
Author(s):  
Josef Jirman ◽  
Antonín Lyčka ◽  
Miroslav Ludwig
Keyword(s):  
Dimethyl Sulfoxide ◽  
Ethyl Acetoacetate ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
15N Nmr ◽  
Carbonyl Groups ◽  
Nmr Chemical Shifts ◽  
Methylene Group ◽  
C Nmr

15N and 13C NMR spectra have been measured of the compounds type XC(=NOH)Y, where X, Y = COCH3, CN, COOR, CONHR, and X +Y = C6H4(CO)2. The (E)-(Z) isomerism at the C=NOH bond has been studied by means of 15N labelling and stereospecific behaviour of the 2J(15N, 13C) coupling constants. The nitrosation of methyl cyanoacetate gives specifically the respective (E)-oxime, whereas that of acetoacetanilide gives the (Z)-isomer. The nitrosation of ethyl acetoacetate gives both (E)- and (Z)-oximes in a ratio of ca 1:10; the (E)-isomer is less stable and is transformed into the (Z)-isomer. The applicability of the 1J(13C, 13C) coupling constants and lanthanoid shift reagents to the study of (E)-(Z) isomerism of oximes with geminal carbonyl groups has also been verified. The 15N NMR chemical shifts of the oximes studied correlate with their respective pKa values measured in dimethyl sulfoxide according to the equation pKa = -0.11δ15N + 13.44.

scholarly journals An Experimental Study of the 4hJ(31P–31P) Coupling Constant and the 12C/13C Isotope Effect on 31P in an Iminophosphorane-Substituted Proton Sponge

2002 ◽  
Vol 2002 (1) ◽  
pp. 34-36
Author(s):  
José Elguero ◽  
Alain Fruchier ◽  
María Luisa Jimeno ◽  
Pedro Molina
Keyword(s):  
Experimental Study ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Coupling Constant ◽  
Proton Sponge ◽  
Nmr Spectrum ◽  
13C Isotope ◽  
C Nmr

The 13C NMR spectra of the bromide of the protonated iminophosphorane -substituted sponge 7 were recorded at different fields. Together with the use of 13C satellites of the 31P NMR spectrum, these experiments allow determination of a reasonable set of chemical shifts and coupling constants. The most interesting are a 4h JPP = 1.6 Hz, determined directly from the 31P NMR spectrum, which probably involves the hydrogen bond, and a 2Δ31P(13C) isotope shift of 9 ppb.

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