Proton, carbon-13, and fluorine-19 NMR study of N-arylpyridinium salts: Attempted calculations of the σ1 and σR0 values for N-pyridinium substituents

1981 ◽  
Vol 46 (3) ◽  
pp. 584-596 ◽  
Author(s):  
Rosa Maria Claramunt ◽  
José Elguero
Keyword(s):  
Electronic Properties ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Nmr Study

The synthesis and NMR study of fourteen N-arylpyridinium salts have been done. Chemical shifts and coupling constants (1H-1H, 1H-13C, 1H-19F, and 13C-19F) have been measured in hexadeuteriodimethyl sulphoxide. Conformation about the phenylpyridinium bond is discussed. The electronic properties of the three pyridinium substituents ( pyridinium, 2,4,6-trimethylpyridinium, and 2,4,6-triphenylpyridinium) have been determined (Hammet and Taft's σ values) and compared with those of the trimethylammonium substituent.

15N NMR study of amino-imino tautomerism in derivatives of 1,4-bis(substituted amino)-9,10-anthraquinones and 1,4-bis(substituted amino)-2,3-dihydro-9,10-anthraquinones

1987 ◽  
Vol 52 (3) ◽  
pp. 736-741 ◽  
Author(s):  
Antonín Lyčka ◽  
Libuše Havlíčková ◽  
Alois Koloničný ◽  
Josef Jirman
Keyword(s):  
Chemical Shifts ◽  
Coupling Constants ◽  
15N Nmr ◽  
Nmr Study ◽  
Derivatives Of ◽  
Tautomeric Mixture

The 15N chemical shifts and 1J(15N, H) coupling constants of 1,4-bis(substituted amino)-9,10-anthraquinones and 1,4-bis(substituted amino)-2,3-dihydro-9,10-anthraquinones indicate that these derivatives exist as true aminoderivatives except for 1,4-bis(phenylamino)-2,3-dihydro-9,10-anthraquinone which forms a tautomeric mixture of the amino and imino forms in deuteriochloroform and hexadeuteriodimethyl sulphoxide.

14N- und 15N-NMR-Spektroskopie von Diazaphospholen und die lineare Korrelation der chemischen Verschiebung von zweifach koordiniertem N und P / 14N and 15N NMR Spectroscopy of Diazaphospholes and the Linear Correlation of the Chemical Shift of Two-Coordinate N and P

1986 ◽  
Vol 41 (5) ◽  
pp. 553-559 ◽  
Author(s):  
Alfred Schmidpeter ◽  
Bernd Wrackmeyer
Keyword(s):  
Linear Correlation ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
15N Nmr ◽  
Ground State Structure ◽  
Nitrogen And Phosphorus ◽  
System A ◽  
Nmr Study ◽  
15N Nmr Spectroscopy ◽  
Scalar Relaxation

A systematic natural abundance 15N NMR study of diazaphospholes is presented for the first time, giving accurate values for chemical shifts, δN , and coupling constants J(31P15N), J(15N1H ). 14N NMR spectra can be used to predict the magnitude of 1J( 31P14N) if the broadening of the 31P resonance by scalar relaxation is known. The relaxation behaviour of the 14N nuclei corresponds to that found in azoles indicating a comparable electronic ground state structure. The comparison of the chemical shifts, δN, in the diazaphospholes with δN of corresponding triazoles reveals differences which can be traced to the N-P σ-bonds and to the influence o f the phosphorus atom on the π-system. A linear correlation δN/δP exists coordinate nitrogen and phosphorus, respectively.

scholarly journals Azapentalenes. XLIV.1H and13C-NMR study of mesoionic pyrazolo[1,2-a]pyrazoles

1997 ◽  
Vol 13 (2) ◽  
pp. 113-123 ◽  
Author(s):  
Rosa María Claramunt ◽  
Sviatoslav Trofimenko ◽  
Isabel Rozas ◽  
José Elguero
Keyword(s):  
Chemical Shifts ◽  
Additive Models ◽  
Coupling Constants ◽  
Pyrazole Derivatives ◽  
1H And13c Nmr ◽  
Nmr Study ◽  
Semi Empirical

The1H and13C chemical shifts as well as the1H–1H and1H–13C coupling constants of sixteen pyrazolo[1,2-a]pyrazole derivatives have been measured. The most relevant features are discussed using resonance forms and simple additive models. AM1 semi-empirical calculations have been carried out to provide a rationale for the NMR results.

13C and 15N NMR study of azo-hydrazone tautomerism in azo dyes containing amino or acetamido groups

1983 ◽  
Vol 48 (11) ◽  
pp. 3104-3111 ◽  
Author(s):  
Antonín Lyčka
Keyword(s):  
Temperature Dependence ◽  
Isotope Effect ◽  
Azo Dyes ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
15N Nmr ◽  
Nmr Study ◽  
Hydrazone Form

13C and 15N NMR spectra of ten model azo dyes containing NH2 or NHCOCH3 group in ortho- or para-position to the phenylazo group on benzene, naphthalene and anthracene skeleton were measured. A negligible content of the hydrazone form in these compounds follows from the 13C and 15N chemical shifts and from a slight temperature dependence of the 15N chemical shifts and 1J(15N15N) coupling constants. The 15N isotope effect Δδ (15N) = 0.1 ppm was observed and the values of 1J(15N15N) = 15.6 ± 0.3 Hz were found with compounds double labelled by 15N.

scholarly journals 1H and13C NMR study of perdeuterated pyrazoles

1997 ◽  
Vol 13 (4) ◽  
pp. 291-294 ◽  
Author(s):  
María Luisa Jimeno ◽  
Nadine Jagerovic ◽  
José Elguero ◽  
Thomas Junk ◽  
W. James Catallo
Keyword(s):  
Chemical Shifts ◽  
Coupling Constants ◽  
1H And13c Nmr ◽  
Nmr Study

The1H and13C chemical shifts as well as the1H–2H and2H–13C coupling constants of perdeuterated 3,5-dimethylpyrazole and 3,5-diphenylpyrazole have been measured and the values compared with those of the unlabelled compounds.

13C NMR study of tetrosides and their derivatives

1980 ◽  
Vol 45 (10) ◽  
pp. 2779-2783 ◽  
Author(s):  
Jiří Urban ◽  
Miroslav Marek ◽  
Jiří Jarý ◽  
Petr Sedmera
Keyword(s):  
13C Nmr ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Direct Coupling ◽  
Coupling Constants ◽  
Anomeric Configuration ◽  
Nmr Study ◽  
C Nmr

13C NMR spectra of 23 tetrose derivatives were assigned. The C(1) resonates below 103 ppm with compounds having cis-arranged substituents at C(1) and C(2) and above 106 ppm with compounds having trans-arrangement. The carbon-13 chemical shifts are mainly influenced by the 1,2-interaction. The magnitudes of direct coupling constants 1J(C(1), H) cannot be used for the determination of the anomeric configuration.

13C NMR study of substituted quinone methides. 2- and 2,6-substituted fuchsones

1981 ◽  
Vol 46 (8) ◽  
pp. 1775-1787 ◽  
Author(s):  
Antonín Lyčka ◽  
Dobroslav Šnobl ◽  
Bohumír Koutek ◽  
Libuše Pavlíčková ◽  
Milan Souček
Keyword(s):  
13C Nmr ◽  
Chemical Shifts ◽  
Substituent Effects ◽  
Coupling Constants ◽  
Quinone Methides ◽  
Nmr Study ◽  
Related Compounds

Carbon-13 chemical shifts and 1J(CH) coupling constants for 11 fuchsones of the types I and II in deuteriochloroform are reported. The assignments are based on an analysis of proton coupled and proton decoupled spectra and on the analogy to chemical shifts of some structuraly related compounds. Satisfactory Swain-Lupton F and R correlations which were found for most of 13C chemical shifts afforded values for percent resonance contributions to transmission of substituent effects as follows, C(1), 19%; C(3), 71%; C(7), 43%. Some alternative correlations for other similar systems e.g. quinones and tropones are also given.

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.

Gradient-Enhanced Inverse-Detected NMR Techniquesfor Determination of 1H-15N Coupling Constants in 2,2-Dimethylpenta-3,4-dienal Derivatives

1997 ◽  
Vol 62 (11) ◽  
pp. 1747-1753 ◽  
Author(s):  
Radek Marek
Keyword(s):  
Double Bond ◽  
Chemical Shifts ◽  
Multiple Bond ◽  
Coupling Constants ◽  
Single Quantum ◽  
Nmr Techniques ◽  
Phase Sensitive ◽  
Heteronuclear Coupling

Determination of 15N chemical shifts and heteronuclear coupling constants of substituted 2,2-dimethylpenta-3,4-dienal hydrazones is presented. The chemical shifts were determined by gradient-enhanced inverse-detected NMR techniques and 1H-15N coupling constants were extracted from phase-sensitive gradient-enhanced single-quantum multiple bond correlation experiments. Stereospecific behaviour of the coupling constants 2J(1H,15N) and 1J(1H,13C) has been used to determine the configuration on a C=N double bond. The above-mentioned compounds exist predominantly as E isomers in deuteriochloroform.

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