Preparation and electron transfer-induced cis-trans isomerization reactions of 1-(5-nitro-2-furyl)-, 1-(5-nitro-2-thienyl)-, and 1-(4-nitrophenyl)-2-R ethylenes

1989 ◽  
Vol 54 (6) ◽  
pp. 1675-1682 ◽  
Author(s):  
Josef Prousek ◽  
Viktor Hayden
Keyword(s):  
Electron Transfer ◽  
Nmr Spectroscopy ◽  
Electron Donor ◽  
Radical Anion ◽  
Wittig Reaction ◽  
H Nmr ◽  
Trans Isomerization ◽  
Ct Complex

Mixtures of E- and Z-isomers of 1,2-bis(5-nitro-2-furyl)ethylene (I), 1-(5-nitro-2-furyl)-2-(4-nitrophenyl)ethylene (II), 1,2-bis(4-nitrophenyl)ethylene (III), 1-(5-methoxycarbonyl-2-furyl)-2-(4-nitrophenyl)ethylene (IV), 1-(5-methoxycarbonyl-2-furyl)-2-(5-nitro-2-furyl)ethylene (V) and 1-(5-methoxycarbonyl-2-furyl)-2-(5-nitro-2-thienyl)ethylene (VI) were prepared by the Wittig reaction. These derivatives were isomerized by electron transfer-induced reactions via the radical anion in the CT-complex using aniline as electron donor at 25 °C in the light or at 80 °C in the dark. The starting as well as the final E:Z ratio was determined by 1H NMR spectroscopy. In all cases only the cis → trans isomerization was observed.

New Nitrogen-Rich Tripodal Molecules Based on Bis(pyrazol-1-ylmethyl)amines with Substituents Modulating Steric Hindrances and Electron Density of Donor Sites

2005 ◽  
Vol 70 (1) ◽  
pp. 34-40 ◽  
Author(s):  
Stefania Garbacia ◽  
Caroline Hillairet ◽  
Rachid Touzani ◽  
Olivier Lavastre
Keyword(s):  
Nmr Spectroscopy ◽  
Electron Density ◽  
Electron Donor ◽  
Primary Amines ◽  
Effect Of Substituents ◽  
H Nmr ◽  
Donor Acceptor ◽  
One Step ◽  
Steric Hindrances

Eight new substituted bis(pyrazol-1-ylmethyl)amines have been prepared in one step condensation of 1-(hydroxymethyl)-3,5-disubstituted pyrazoles with a series of primary amines. The effect of substituents of divers bulkiness and electron donor/acceptor power that have been introduced to these tridentate molecules is visualised by 1H NMR spectroscopy.

scholarly journals Photoisomerisierung von trans-1-(3.5-Di-tert-butyl-4-hydroxyplienyl)-2-phenyldiazen / Photoisomerization of trans-1-(3,5-Di-tert-butyl-4-hydroxyphenyl)-2-phenyldiazene

1980 ◽  
Vol 35 (2) ◽  
pp. 233-236 ◽  
Author(s):  
Edgar Hofer
Keyword(s):  
Nmr Spectroscopy ◽  
Title Compound ◽  
Tautomeric Equilibrium ◽  
Tert Butyl ◽  
H Nmr ◽  
Nmr Data ◽  
Trans Isomerization ◽  
Different Temperatures ◽  
Influence Of Solvent

AbstractLight induced isomerizations of the title compound have been studied. The thermal cis-trans isomerization 3→1 occurs via the tautomeric quinonephenylhydrazone (2) as shown by 1H NMR, spectroscopy. The influence of solvent on the thermal cis-trans isomerization is discussed. 1H NMR data of 1, 2 and 3 are given. Values of the tautomeric equilibrium 1⇋2 are determined for various solvents and different temperatures.

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.

Redox properties and electron transfer in a triarylamine-substituted HS-Co2+/LS-Co3+ redox couple

2017 ◽  
Vol 46 (8) ◽  
pp. 2690-2698 ◽  
Author(s):  
Linda Schnaubelt ◽  
Holm Petzold ◽  
J. Matthäus Speck ◽  
Evgenia Dmitrieva ◽  
Marco Rosenkranz ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Nmr Spectroscopy ◽  
Redox Properties ◽  
Redox Couple ◽  
H Nmr ◽  
Electron Transfer Properties ◽  
Transfer Properties

The redox and electron transfer properties of a triarylamine decorated HS-Co2+/LS-Co3+ redox couple were investigated by coupled EPR/UV-vis-NIR spectroelectrochemistry and 1H NMR spectroscopy.

Conformational study on ribonucleoside O-phosphonylmethyl derivatives by 1H NMR spectroscopy

1985 ◽  
Vol 50 (8) ◽  
pp. 1899-1905 ◽  
Author(s):  
Milena Masojídková ◽  
Jaroslav Zajíček ◽  
Miloš Buděšínský ◽  
Ivan Rosenberg ◽  
Antonín Holý
Keyword(s):  
Nmr Spectroscopy ◽  
1H Nmr ◽  
1H Nmr Spectroscopy ◽  
Conformational Study ◽  
H Nmr ◽  
Conformational Properties

Conformational properties of ribonucleoside 5'-O-phosphonylmethyl derivatives have been determined by 1H NMR spectroscopy and compared with those of natural nucleosides and 5'-nucleotides.

Monitoring the encapsulation of chlorin e6 derivatives into polymer carriers by NMR spectroscopy

2019 ◽  
Vol 23 (11n12) ◽  
pp. 1576-1586 ◽  
Author(s):  
Sara Pfister ◽  
Luca Sauser ◽  
Ilche Gjuroski ◽  
Julien Furrer ◽  
Martina Vermathen
Keyword(s):  
Relaxation Time ◽  
Nmr Spectroscopy ◽  
Core Region ◽  
Chlorin E6 ◽  
Polypropylene Glycol ◽  
Polymer Carriers ◽  
H Nmr ◽  
Line Shape Analysis ◽  
Dynamic Methods ◽  
Derivatives Of

The encapsulation of five derivatives of chlorin e6 with different hydrophobicity and aggregation properties into a series of five poloxamer-type triblock copolymer micelles (BCMs) with varying numbers of polyethylene and polypropylene glycol (PEG, PPG) units was monitored using 1H NMR spectroscopy. NMR chemical shift and line shape analysis, as well as dynamic methods including diffusion ordered spectroscopy (DOSY) and T1 and T2 relaxation time measurements of the chlorin and the polymer resonances, proved useful to assess the chlorin–BCM compatibility. The poloxamers had high capability to break up aggregates formed by chlorins up to intermediate hydrophobicity. Physically entrapped chlorins were always localized in the BCM core region. The loading capacity correlated with chlorin polarity for all poloxamers among which those with the lowest number of PPG units were most efficient. DOSY data revealed that relatively weakly aggregating chlorins partition between the aqueous bulk and micellar environment whereas more hydrophobic chlorins are well retained in the BCM core region, rendering these systems more stable. T1 and T2 relaxation time measurements indicated that motional freedom in the BCM core region contributes to encapsulation efficiency. The BCM corona dynamics were rather insensitive towards chlorin entrapment except for the poloxamers with short PEG chains. The presented data demonstrate that 1H NMR spectroscopy is a powerful complementary tool for probing the compatibility of porphyrinic compounds with polymeric carriers such as poloxamer BCMs, which is a prerequisite in the development of stable and highly efficient drug delivery systems suitable for medical applications like photodynamic therapy of tumors.

Different submicellar solubilization mechanisms revealed by 1H NMR and 2D diffusion ordered spectroscopy (DOSY)

2020 ◽  
Vol 22 (19) ◽  
pp. 11075-11085
Author(s):  
Mengjian Wu ◽  
Zhaoxia Wu ◽  
Shangwu Ding ◽  
Zhong Chen ◽  
Xiaohong Cui
Keyword(s):  
Nmr Spectroscopy ◽  
Sodium Dodecyl Sulfate ◽  
1H Nmr ◽  
Sodium Dodecyl ◽  
Butyl Methacrylate ◽  
H Nmr ◽  
Molecular Scale ◽  
Two Systems ◽  
Dodecyl Sulfate ◽  
Triton X

Different submicellar solubilization mechanisms of two systems, Triton X-100/tetradecane and sodium dodecyl sulfate (SDS)/butyl methacrylate, are revealed on the molecular scale by 1H NMR spectroscopy and 2D diffusion ordered spectroscopy (DOSY).

scholarly journals Synthesis of an elusive, stable 2-azaallyl radical guided by electrochemical and reactivity studies of 2-azaallyl anions

2021 ◽  
Author(s):  
Grace B. Panetti ◽  
Patrick J. Carroll ◽  
Michael R. Gau ◽  
Brian C. Manor ◽  
Eric J. Schelter ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Electron Donor ◽  
Transfer Characteristics

The super electron donor (SED) capabilities of 2-azaallyl anions has recently been discovered and applied to diverse reactivity; their structures and electron transfer characteristics are reported herein.

scholarly journals Tautomerisation in 1-(4-Methylphenylazo)naphthalen-2-ol and 2-(4-Methylphenylazo)-4-methylphenol: A Crystallographic and 13C{1H}NMR Study

1999 ◽  
Vol 23 (3) ◽  
pp. 178-179
Author(s):  
Wendy I. Cross ◽  
Kevin R. Flower ◽  
Robin G. Pritchard
Keyword(s):  
Acetic Acid ◽  
Nmr Spectroscopy ◽  
Resonant Frequency ◽  
X Ray Diffraction ◽  
X Ray ◽  
H Nmr ◽  
Nmr Study ◽  
Acetic Acid Esters ◽  
Acid Esters ◽  
Equivalent Carbon

The acetic acid esters of 1-(4-methylphenylazo)naphthalen-2-ol 1 and 2-(4-methylphenylazo)-4-methylphenol 3 are prepared and characterised by single crystal X-ray diffraction studies and 13C{1H}NMR spectroscopy; the position of the C(2)13C resonance for the ester is used to predict the position of resonant frequency of the equivalent carbon in the parent alcohols and hence, calculate the position of the azo-hydrazone equilibrium in these compounds.

3-Hydroxy Retinal, a New Chromophore Identified in Insect Eyes: HPLC Separation and NMR Spectroscopic Identification of the Oxime Forms

1988 ◽  
Vol 43 (5-6) ◽  
pp. 473-475 ◽  
Author(s):  
Wolfgang Gärtner ◽  
Anette Plangger
Keyword(s):  
Nmr Spectroscopy ◽  
Separation System ◽  
Hplc Separation ◽  
H Nmr ◽  
Spectroscopic Identification

3-Hydroxy retinal acts as visual chromophore instead of retinal in the eyes of several insect orders. A HPLC separation system of the aldehyde and oxime isomers and their identification by 400 MHz 1H NMR spectroscopy is described.

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