Effect of the π-Electron Ring Current on the 1H NMR Spectra of 1,1'-Binaphthol Derivatives

1993 ◽  
Vol 58 (1) ◽  
pp. 77-81 ◽  
Author(s):  
Gustavo Marin-Puga ◽  
Václav Horák ◽  
Paris Svornos
Keyword(s):  
High Resolution ◽  
1H Nmr ◽  
Nmr Spectra ◽  
Close Agreement ◽  
Ring Current ◽  
Chemical Shifts ◽  
Current Effect ◽  
H Nmr ◽  
Ring Current Effect ◽  
Cosy Nmr

High resolution 1H NMR spectra of two 1,1'-binaphthols (I, II), two 1,1'-binaphthalenediols (III, IV) and four 1,1'- binaphthalenediols acetates (IIIa - IVa) were obtained and analyzed. The effect of the ring current was evaluated by comparing the chemical shifts of the compounds, assigned through H-H COSY NMR experiments, to those of the corresponding monomers. All experimental chemicals shifts are in close agreement with the theoretical values obtained via the Bovey model for the ring current effect of a benzene moiety.

scholarly journals 13C and 1H NMR Spectra of Synthetic (25R)-5α-Spirostanes

1999 ◽  
Vol 23 (1) ◽  
pp. 48-49
Author(s):  
Martín A. Iglesias Arteaga ◽  
Carlos S. Pérez Martinez ◽  
Roxana Pérez Gil ◽  
Francisco Coll Manchado
Keyword(s):  
1H Nmr ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
1H Nmr Spectra ◽  
H Nmr ◽  
C 23 ◽  
Main Effects ◽  
Nmr Signals

The assignment of 13C and 1H NMR signals of synthetic (25 R)-5α-spirostanes is presented; the main effects on chemical shifts due to substitution at C-23 are briefly discussed.

Synthesis and photophysical studies of non-covalently linked porphyrin dyads and triads

2007 ◽  
Vol 11 (02) ◽  
pp. 85-94 ◽  
Author(s):  
Punidha Sokkalingam ◽  
Sangita Santra ◽  
Ravikanth Mangalampalli
Keyword(s):  
Ring Current ◽  
Singlet State ◽  
Photophysical Properties ◽  
Spectroscopic Techniques ◽  
Current Effect ◽  
H Nmr ◽  
Nmr Study ◽  
Photophysical Studies ◽  
Ring Current Effect ◽  
Covalently Linked

Non-covalent porphyrin dyads and triads containing N 3 S porphyrin and RuN 4 porphyrin subunits were synthesized by treating meso-pyridyl-21-thiaporphyrin with RuTPP(CO)(EtOH) in toluene at refluxing temperature. The dyads and triads were characterized by various spectroscopic techniques and the properties were compared with the reported dyad containing N 4 and RuN 4 porphyrin subunits. The 1 H NMR study of dyads and triads indicated that the inner NH , β-heterocycle and meso-pyridyl protons of the 21-thiaporphyrin unit experienced large upfield shifts as compared to their corresponding monomeric meso-pyridyl-21-thiaporphyrins due to the ring current effect of RuTPP(CO) subunit. The singlet state photophysical properties of N 3 S porphyrin subunit in dyads and triads showed 50-80% quenching of fluorescence as observed previously for N 4- RuN 4 dyad due to heavy ruthenium ion(s).

13C-NMR chemische Verschiebung phenylsubstituierter polycyclischer Kohlenwasserstoffe / 13C-NMR Chemical Shift of Phenylsubstituted Polycyclic Hydrocarbons

1979 ◽  
Vol 34 (11) ◽  
pp. 1334-1343 ◽  
Author(s):  
W. Storek ◽  
J. Sauer ◽  
R. Stößer
Keyword(s):  
Chemical Shift ◽  
13C Nmr ◽  
Nmr Spectra ◽  
Ring Current ◽  
Current Effect ◽  
Nmr Data ◽  
Ring Current Effect ◽  
Anisotropic Contribution ◽  
Chemische Verschiebung ◽  
C Nmr

13C-NMR spectra of tetracene, rubrene, 1,3,5-tri-, penta-, and hexaphenylbenzene are reported. The discussion also includes the already known 13C-NMR data for diphenyl, 9,10-diphenyl-, 9,10-dibenzyl-, and 9,10-dimethyl-anthracene [1] as well as toluene. On the basis of CNDO/2 calculations different influences (diamagnetic and paramagnetic term, anisotropic contribution, ring current effect, geometry) on the chemical shift are analyzed for diphenyl and within the row benzene through tetracene

15N, 13C, and 1H NMR spectra of acylated ureas and thioureas

1987 ◽  
Vol 52 (10) ◽  
pp. 2474-2481 ◽  
Author(s):  
Josef Jirman ◽  
Antonín Lyčka
Keyword(s):  
1H Nmr ◽  
Electron Acceptor ◽  
Sulfur Atom ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
1H Nmr Spectra ◽  
Coupling Constants ◽  
Nmr Chemical Shifts ◽  
H Nmr ◽  
Better Than

A series of 1-acylated and 1,3-diacylated (acyl = acetyl or benzoyl) ureas and thioureas have been prepared and their proton-coupled and proton-decoupled 15N, 13C, and 1H NMR spectra have been measured. All the signals have been assigned. The 15N NMR chemical shifts in 1-acylated ureas and thioureas are shifted downfield as compared with δ(15N) of urea and thiourea, resp. This shift is greater for N-1 than for N-3 nitrogen atoms in both the series. When comparing acylureas and acylthioureas it is obvious from the Δδ(15N) differences that the CS group is better than CO group in transferring the electron-acceptor effect of acyl group. The proton-coupled 15N NMR spectra of the acylureas dissolved in hexadeuteriodimethyl sulphoxide exhibit a doublet of NH group and a triplet of NH2 group at 25 °C. At the same conditions the acylthioureas exhibit a doublet of NH group, the NH2 group signal being split into a doublet of doublets with different coupling constants 1J(15N, H). The greater one of these coupling constants is due to the s-trans proton with respect to the sulfur atom of the thiourea.

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.

Methyl chemical shifts in 1H-NMR spectra of 1-R-2,4,6-trimethylpyridinium salts as simple probes for the existence and magnitude of ring current in group R

1979 ◽  
Vol 20 (5) ◽  
pp. 437-440 ◽  
Author(s):  
Alexandru T. Balaban ◽  
Antonie Dinculescu ◽  
Hristos N. Koutrakis ◽  
Filip Chiraleu
Keyword(s):  
1H Nmr ◽  
Nmr Spectra ◽  
Ring Current ◽  
Chemical Shifts ◽  
1H Nmr Spectra

Effect of lanthanide shift reagents on 1H NMR spectra of aminopyridines

1979 ◽  
Vol 44 (3) ◽  
pp. 908-911 ◽  
Author(s):  
Antonín Lyčka ◽  
Dobroslav Šnobl
Keyword(s):  
Nmr Spectroscopy ◽  
1H Nmr ◽  
Electron Donor ◽  
Electron Acceptor ◽  
Nmr Spectra ◽  
Pyridine Ring ◽  
Chemical Shifts ◽  
Amino Group ◽  
H Nmr ◽  
Lanthanide Shift Reagents

The effect of Eu(dpm)3 and Pr(dpm)3 on the proton spectra of 2-amino-, 3-amino- and 4-aminopyridines has been studied by the 1H NMR spectroscopy in tetrachlomethane and deuteriochloroform at 25 °C. Relative changes of the induced chemical shifts of pyridine carrying electron-donor substituents (amino group) are the same as the values given in literature for pyridine ring with electron-acceptor substituents.

15N, 13C, and 1H NMR spectra of 1-substituted-2,4,6-trinitrobenzenes

1987 ◽  
Vol 52 (12) ◽  
pp. 2946-2952 ◽  
Author(s):  
Antonín Lyčka ◽  
Vladimír Macháček ◽  
Josef Jirman
Keyword(s):  
1H Nmr ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
1H Nmr Spectra ◽  
H Nmr

The 15N, 13C, and 1H NMR spectra of twenty 1-substituted-2,4,6-trinitrobenzenes have been measured in hexadeuteriodimethyl sulphoxide. The δ(15N) chemical shifts of 2-NO2 and 6-NO2 groups are different from those of 4-NO2 group. Except for 1-(4-subst. phenoxy)derivatives, the δ(15N-4) are shifted upfield as compared with δ(15N-2,6). The assignment of signals in the 15N NMR spectra was confirmed in three cases by measurements of selectively 15N-labelled compounds.

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