NMR Complexation Study of Several Oxyethylated Calix[4]arenes with Lithium, Sodium and Potassium Ions

1996 ◽  
Vol 61 (12) ◽  
pp. 1783-1797 ◽  
Author(s):  
Jaroslav Havlíček ◽  
Marcela Tkadlecová ◽  
Michaela Vyhnánková ◽  
Evgueni Pinkhassik ◽  
Ivan Stibor
Keyword(s):  
Sodium Cation ◽  
H Nmr ◽  
Nmr Data ◽  
Constant Determination ◽  
Close Proximity ◽  
Dinitro Derivative ◽  
The Stability ◽  
Upper Rim ◽  
Sodium And Potassium ◽  
C Nmr

The influence of calix[4]arene upper rim substitution on the complexation with Li+, Na+, K+ was studied by 1H NMR spectroscopy. Calix[4]arenes 1-4 namely 25,26,27,28-tetrakis(3-oxapentyloxy)calix[4]arene (1), its 5,17-diamino (2) and 5,17-dinitro derivative (3) as well as 25,26,27,28-tetrakis(3,6,9-trioxadecyloxy)calix[4]arene (4) having four monoalkyloligoethylene glycol chains on the lower rim have been studied. No complexation has been observed for Li+. Two electron-donating NH2 groups on the calixarene upper rim (compound 2) improve the complexation ability for Na+ and K+ compared with parent calixarene 1. The electron-withdrawing nitro groups in 3 have the opposite influence. It seems that the complexation of alkali metal ions studied is not significantly influenced by the increasing number of donor atoms (from eight in 1 to sixteen in 4) available for complexation on the lower rim. The position of sodium cation in 1 . Na+ and 4. Na+ is supposed to be in close proximity of phenolic oxygens based on 1H and 13C NMR data. The error analysis is given for the stability constant determination from NMR data.

A kinetic and nuclear magnetic resonance study of methylated pyrimidine nucleosides

1983 ◽  
Vol 61 (10) ◽  
pp. 2397-2402 ◽  
Author(s):  
B. D. Allore ◽  
A. Queen ◽  
W. J. Blonski ◽  
F. E. Hruska
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Ph Dependence ◽  
Nuclear Magnetic Resonance Study ◽  
Magnetic Resonance Study ◽  
Pyrimidine Nucleosides ◽  
Spectrophotometric Methods ◽  
H Nmr ◽  
Nmr Data ◽  
The Stability ◽  
C Nmr

Alkylated pyrimidine nucleosides are of interest from the viewpoint of mutagenesis and carcinogenesis. 1H and 13C nmr data are presented for a series of 2′-deoxynucleosides methylated at the O2-, O4-, and N3-positions of the base, and discussed in terms of their physical properties. The pH dependence of the stability of the O2- and O4-methylated 2′-deoxyribosides as well as the corresponding ribosides was examined by 1H nmr and ultraviolet (uv) spectrophotometric methods.

scholarly journals Synthesis of Some Novel Fused Imidazo [2, 1-b] [1, 3] Thiazole and Imidazo [2, 1-b] Thiazolo [5, 4-d] Isoxazole Derivatives

2012 ◽  
Vol 9 (3) ◽  
pp. 1518-1525 ◽  
Author(s):  
Hamid Reza Jaberi ◽  
Hadi Noorizadeh
Keyword(s):  
Acetic Acid ◽  
Sodium Acetate ◽  
Carbon Disulphide ◽  
Thiazole Derivatives ◽  
H Nmr ◽  
Nmr Data ◽  
Elemental Analyses ◽  
New Compounds ◽  
Isoxazole Derivatives ◽  
C Nmr

In this work we describe the synthesis of some novel fused imidazo [2, 1-b] [1, 3] thiazole derivatives. The reaction of 1, 2-diaminoethane 1 with carbon disulphide in H2O/ETOH as solvent furnishes 4, 5-dihydro-1H-imidazol-2-thiol 2 under reflux condition. the reaction of 4,5-dihydro-1H-imidazol-2-thiol on treatment with ethylchloro acetate and aromatic aldehyde in presence of anhydrous sodium acetate and acetic acid as solvent to give (Z)-2-(arylidene)-5,6-dihydroimidazo [2,1-b] [1,3] thiazol-3(2H)-one 3a-j. Compounds 3a-j was condensed with hydroxylamine to give 3-(aryl)-2, 3, 6, 7-tetrahydroimidazo [2, 1-b] [1,3] thiazolo [5, 4-d] isoxazole 4a-j. The structures of the new compounds were established by elemental analyses, IR,1H NMR and13C NMR data.

scholarly journals Synthesis and Spectroscopic Characterization of Some New Axially Ligated Indium(III) Macrocyclic Complexes and Their Biological Activities

2014 ◽  
Vol 2014 ◽  
pp. 1-7
Author(s):  
Gauri D. Bajju ◽  
Altaf Ahmed ◽  
Deepmala Gupta ◽  
Ashu Kapahi ◽  
Gita Devi
Keyword(s):  
Biological Activities ◽  
Spectroscopic Characterization ◽  
Axial Ligand ◽  
Free Base ◽  
H Nmr ◽  
Pyramidal Geometry ◽  
The Stability ◽  
Square Pyramidal Geometry ◽  
C Nmr

The synthesis and spectroscopic characterization of new axially ligated indium(III) porphyrin complexes were reported. Chloroindium(III) porphyrin (TPPIn-Cl) was obtained in good yield by treating the corresponding free base with indium trichloride. The action of the different phenols on chloroderivatives (TPPIn-Cl) led to the corresponding phenolato complexes (TPPIn-X). These derivatives were characterized on the basis of mass spectrometry,1H-NMR, IR, and UV-visible data. The separation and isolation of these derivatives have been achieved through chromatography. The spectral properties of free base porphyrin and its corresponding metallated and axially ligated indium(III) porphyrin compounds were compared with each other. A detailed analysis of UV-Vis,1H-NMR, and IR suggested the transformation from free base porphyrin to indium(III) porphyrin. Besides,13C-NMR and fluorescence spectra were also reported and interpreted. The stability of these derivatives has also been studied through thermogravimetry. The complexes were also screened for anticancerous activities. Among all the complexes, 4-MePhO-InTPP shows highest anticancerous activity. The title complexe, TPPIn-X (where X = different phenolates), represents a five-coordinate indium(III) porphyrin complex in a square-pyramidal geometry with the phenolate anion as the axial ligand.

scholarly journals Molecular Encapsulation of Herbicide Terbuthylazine in Native and Modifiedβ-Cyclodextrin

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
E. Manuela Garrido ◽  
Daniela Rodrigues ◽  
Nuno Milhazes ◽  
Fernanda Borges ◽  
Jorge Garrido
Keyword(s):  
Water Solubility ◽  
Analytical Techniques ◽  
Aqueous Solubility ◽  
Mean Values ◽  
H Nmr ◽  
Nmr Data ◽  
Kneading Method ◽  
Other Substances ◽  
The Mean ◽  
The Stability

The herbicide terbuthylazine (TBA) is widely used for preemergence or postemergence control of many grass and broadleaf weeds and has, besides other issues, a poor aqueous solubility profile that results in reduced bioavailability. Cyclodextrins and modified cyclodextrins were considered, among other substances, appropriate agents for improving pesticide water solubility. Therefore, the inclusion complex formation of terbuthylazine withβ-cyclodextrin (β-CD) and hydroxypropyl-β-cyclodextrin (HP-β-CD) was studied to attain its aqueous solubility enhancement. Their characterization was accomplished with different analytical techniques, namely, by UV-Vis, DSC, FTIR, and1H NMR. From the analysis of the complexation performance of the herbicide it was concluded that the interaction of terbuthylazine with CDs leads to the formation of inclusion complexes with a stoichiometry of 1 : 1. The association constants of the TBA/β-CD and TBA/HP-β-CD complexes were determined by UV. The mean values obtained for the stability constants are 460.4 ± 26.5 and 532.1 ± 27.6 to TBA/β-CD and TBA/HP-β-CD, respectively.1H NMR data corroborate the formation of the TBA/β-CD and TBA/HP-β-CD complexes synthesized by the kneading method. A formulation incorporating TBA cyclodextrin complexes might lead to an improvement in terbuthylazine bioavailability. The development of TBA-CD formulations may be interesting since it would enable, through their inclusion into the hydrophobic cavity of CDs, enhancement of solubility, bioavailability, and stability of the herbicide.

Characterization of the 2,2′-bipyridine chelates of lanthanum(III) in acetonitrile. A 1H, 13C, 17O, and 139La NMR study

1993 ◽  
Vol 71 (3) ◽  
pp. 377-383 ◽  
Author(s):  
Monique Fréchette
Keyword(s):  
Coordination Sphere ◽  
Chemical Shifts ◽  
Complexation Reaction ◽  
Complex Species ◽  
H Nmr ◽  
Nmr Data ◽  
Nmr Study ◽  
Close Proximity ◽  
Coordinated Water

We have investigated the reaction between La(NO3)3•6H2O and 2,2′-bipyridine (bipy) in acetonitrile by means of 139La, 17O, 13C, and 1H NMR spectroscopy. The 139La spectra show up to three different sites with variable intensities attributed to solvated La(III) ions and to two complex species with one or two bipy moieties in the La(III) coordination sphere. 17O NMR indicates that during the complexation reaction, the coordinated water is totally displaced from the coordination sphere whereas the nitrate groups remain coordinated. Proton NMR data confirm the water expulsion. In addition, the proton chemical shifts of bipy, in comparison with the 13C NMR data, clearly show an anisotropic shielding when two bipy are coordinated to La(III). Therefore, the two bipy molecules are in close proximity in the coordination sphere. From the NMR results it has been shown that, during the complexation process, five different La(III) species are formed: [La(NO3)3(CH3CN)4], [La(NO3)3(CH3CN)3(H2O)], [La(NO3)3(bipy)(CH3CN)2], [La(NO3)3(bipy)(CH3CN)-(H2O)], and [La(NO3)3(bipy)2]. Each La(III) complex has a coordination member of 10, with NO3− and bipy acting as chelating ligands. Furthermore, the structure of the La(NO3)3(bipy)2 complex in solution shows similarities with the solid state compound. Finally, comparisons are made with the La(III) complexes previously obtained with 1,10-phenanthroline.

Anwendungen der 2 D-NMR-Spektroskopie in der Organophosphorchemie Beispiel: L-Menthyldichlorphosphan / Applications of the 2D NMR Spectroscopy in the Organophosphorus Chemistry Example: L-Menthyldichlorophosphine

1982 ◽  
Vol 37 (12) ◽  
pp. 1661-1664 ◽  
Author(s):  
Martin Feigel ◽  
Gerhard Hägele ◽  
Axel Hinke ◽  
Gudrun Tossing
Keyword(s):  
Nmr Spectroscopy ◽  
2D Nmr ◽  
2D Nmr Spectroscopy ◽  
H Nmr ◽  
Nmr Parameters ◽  
Nmr Data ◽  
Organophosphorus Chemistry ◽  
C Nmr

2D NMR ist used to determine the 1H NMR parameters of L-Menthyldichlorophosphine. 13C NMR data are given

A contribution to peroxy acid oxidation of α,β-unsaturated ketones and linearly conjugated dienones: Reactions in the cholestane series

1988 ◽  
Vol 53 (7) ◽  
pp. 1549-1567 ◽  
Author(s):  
Václav Černý ◽  
Miloš Buděšínský ◽  
Miloš Ryba ◽  
František Tureček
Keyword(s):  
Double Bond ◽  
Carbonyl Group ◽  
Acid Oxidation ◽  
Peroxy Acid ◽  
Unsaturated Ketones ◽  
H Nmr ◽  
Nmr Data ◽  
Epoxy Ketones ◽  
C Nmr

Oxidation with 3-chloroperoxybenzoic acid of s-cis α,β-unsaturated ketones IX, XI and s-trans types X, XII was compared. The s-cis ketones show higher reactivity and furnish a higher yield of the corresponding α,β-epoxy ketones than the s-trans ketones. Products of the Baeyer-Villiger reaction are formed only in low yield. The dienone VI is oxidized predominantly to VII thus violating the rule that linear conjugated dienones are epoxidized at the double bond more distant from the carbonyl group; this result is in accord with the behaviour of s-cis α,β-unsaturated ketones. 1H NMR and 13C NMR data of the starting compounds and of the products are reported.

Chemical stability of CVD source materials for high-Tc superconducting films

1992 ◽  
Vol 7 (6) ◽  
pp. 1336-1340 ◽  
Author(s):  
Takuya Hashimoto ◽  
Hideomi Koinuma ◽  
Masaaki Nakabayashi ◽  
Tadashi Shiraishi ◽  
Youichi Suemune ◽  
...  
Keyword(s):  
Chemical Stability ◽  
Room Temperature ◽  
Chemical Vapor ◽  
Superconducting Films ◽  
Adsorbed Species ◽  
High Tc ◽  
H Nmr ◽  
The Stability ◽  
Source Materials ◽  
C Nmr

The stability of chemical vapor deposition (CVD) source materials for high-Tc superconducting films was examined by 1H-NMR (nuclear magnetic resonance), 13C-NMR, IR (infrared) absorption, and TG-DTA (thermogravimetry and differential thermal analysis) measurements. Highly purified Ca(DPM)2 (DPM: dipyvaloylmethane: (CH3)3CCOCHCOC(CH3)3) and Sr(DPM)2, utilizing recrystallization and sublimation, easily decomposed at room temperature and changed their thermal properties when they were handled and stored in air or even in an Ar atmosphere without removing adsorbed species such as water. The stability increased by removing a trace of adsorbed species and storing in an Ar atmosphere at −30 °C. Bi(C6H5)3 and Y(DPM)3 showed higher chemical stability than Ca(DPM)2 and Sr(DPM)2.

A New Flavonol Glycoside Derivative from Leaves of Moldenhawera nutans

2005 ◽  
Vol 60 (1-2) ◽  
pp. 45-49 ◽  
Author(s):  
Ademir E. do Vale ◽  
Jorge M. David ◽  
Hugo N. Brandão ◽  
Juceni P. David
Keyword(s):  
Ethyl Acetate Extract ◽  
Antioxidant Activities ◽  
Radical Scavenging ◽  
Dpph Radical ◽  
H Nmr ◽  
Nmr Data ◽  
Phytochemical Studies ◽  
Dpph Radical Scavenging ◽  
Β Carotene ◽  
C Nmr

The ethyl acetate extract of leaves of Moldenhawera nutans Queiroz & Alkin (Leguminosae) furnished, besides methyl gallate and gallic acid, the flavonols named laricetrin, laricetrin 3-glucoside and laricetrin 3-galactoside as well as the new one named laricetrin 5-galloyl-3- β-ᴅ-xylopyranoside. It also was isolated from the hexane extract: β-sitosterol, lupenone, β- amyrinone, α-amyrinone, lupeol, β-amyrin, α-amyrin and α-tocopherol. The antioxidant activities of flavonoids were measured through DPPH radical scavenging and inhibition of auto-oxidation of β-carotene methods. The structures of the compounds were determined by analyses of spectral data. This is the first report dealing with phytochemical studies of leaves of M. nutans. In addition this current work describes the unequivocal attribution of 1H NMR and 13C NMR data of laricetrin.

Identification of acyl groups occurring in sesquiterpene lactones: Proton and carbon-13 NMR study

1987 ◽  
Vol 52 (2) ◽  
pp. 453-475 ◽  
Author(s):  
Miloš Buděšínský ◽  
David Šaman
Keyword(s):  
Chemical Shifts ◽  
Sesquiterpene Lactones ◽  
Nmr Chemical Shifts ◽  
H Nmr ◽  
Nmr Parameters ◽  
Nmr Data ◽  
Nmr Study ◽  
C Nmr

Characteristic 1H NMR parameters of 88 acyl groups, hitherto found as ester substituents in natural sesquiterpenic lactones, were determined from the measured spectra as well as literature data. Characteristic 13C NMR chemical shifts for 45 acyl groups were obtained in the same way; for the remaining acyls with hitherto unknown 13C NMR data the values were calculated on the basis of semiempirical relationships.

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