1H NMR spectra of diastereomeric 1,4-disubstituted 2,3-diphenylbutanes; examples of ABXX′ A′B′ and A2XX′A2′ spin systems

The ¹H NMR spectra of the meso- and (±)-forms of some 1,4-disubstituted 2,3-diphenylbutanes were measured at 400 MHz. The spectral parameters were determined by iterative computer analysis, treating the protons as ABXX′A′B′ or (in some cases) A₂XX′A₂′ systems.     

Rotational isomerism—XVI: The AA′BB′X NMR spectrum and rotational isomerism of 2-fluoroethyl trichloroacetate

The complete AA′BB′X analysis of the ¹H and ¹⁹F NMR spectrum of CH₂F.CH₂OCO·CCl₃ ( 1 ) as a neat liquid and in various solvents is given and considered in detail. The differentiation of the two conjugate solutions is obtained both from the X spectrum and by analysis at two field strengths. The coupling constants obtained show that the compound exists almost entirely in the gauche rotamer in all solvents.     

High resolution 1H NMR spectra of 2,2′-biquinoline

From analysis and refinement by the LAOCOON III program of the 220 MHz ¹H spectrum of 2,2′-biquinoline, recorded as a saturated solution in carbon disulphide, most derived chemical shifts and coupling constants are close to corresponding values in quinoline. However, H-3 is at 1.5 ppm lower field in 2,2′-biquinoline than in quinoline and the ortho-coupling ³J(34) in the heterocyclic ring is 0.5 Hz larger in 2,2′-biquinoline than in quinoline; fairly free rotation about the 2,2′ bond is inferred.     

Laser Induced Excitation Spectra of the Cations of Some Fluoro-substituted Phenols (B̃2 A″ ↔ X̃2 A″) in the Gaseous Phase

Excitation spectra of the cations of pentafluorophenol, 2,3,4-trifluorophenol, 2,4,5-trifluorophenol, 2,5-difluorophenol and 3,5-difluorophenol have been obtained by pumping the B?² A″ ← X?²A″ transition with a dye laser. The cations were first produced in their ground states by Penning ionisation using argon metastables. Vibrational frequencies of some of the fundamentals have been inferred for these cations in the B?² A″ state from the excitation spectra, and in the X?² A″ state from the emission spectra. Possible applications of the reported results are suggested.     

Die Chelatbildung von N-Tris(2-aminoethyl)amin-N′,N′,N″,N″,N‴,N‴-hexaessigsäure (H6TTAHA) und N-(Pyrid-2-yl-methyl)ethylendiamin-N,N′,N′-triessigsäure (H3PEDTA) mit Gadolinium(III) – Synthesen,Komplexstabilität und NMR-Relaxivität

Chelate Formation of N-Tris(2-aminoethyl)amine-N′,N′,N″,N″,N?,N?-hexaacetic Acid (H₆TTAHA) and N-(Pyrid-2-yl-methyl)ethylenediamine-N,N′,N′-triacetic Acid (H₃PEDTA) with Gadolinium(III) – Syntheses, Stability Constants, and NMR-Relaxivities The chelate formation of N-tris(2-aminoethyl)amine-N′,N′,N″,N″,N?,N?-hexaacetic acid (H₆TTAHA) and N-(pyrid-2-yl-methyl)ethylenediamine-N,N′,N′-triacetic acid (H₃PEDTA) with gadolinium(III) has been studied potentiometrically in aqueous solution at 25°C and μ = 0.1 (KCl). [Gd(TTAHA)]^3?: 1gβ_M/ML = 19.0; {H[Gd(TTAHA)]}^2?: 1gK_H/MHL = 8.30; [Gd(PEDTA)]: 1gβ_M/ML = 15.56. Both 1 : 1 gadolinium(III) complexes were isolated as Na₂H[Gd(C₁₈H₂₄N₄O₁₂)] · 3.5 H₂O and [Gd(C₁₄H₁₆N₃O₆)] · 3 H₂O, respectively. Their ¹H-NMR relaxivities [1 · mmol^?1 · s^?1] ({H[Gd(TTAHA)]}^2?: 9.5; [Gd(PEDTA)]: 8.8) offer promising applications for ¹H-NMR imaging.     

Mass spectra of B,B′-disubstituted bis(amino)diboranes(4)

The mass spectra of five B,B′-disubstituted derivatives of the bis(amino)diboranes(4). Most of the fragmentations postulated have a precedent in similar processes of isoelectronic and/or isopolar species and are supported by the occurrence of metastable peaks.     

31P-{1H} NMR spectra of some o-tolylbis (triphenylphosphine)nickel derivatives

Conclusion ³¹P NMR spectroscopy was used to show that o-tolylbis(triphenylphosphine)nickel carboxylates may exist in solution in two forms. A study of the exchange reactions of these complexes with triphenylphosphine indicated that the difference between these forms is a consequence of the chelation or lack of chelation of the nickel atom with the carboxylate group oxygen.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1028–1031, May, 1988.     

Chemical behaviours of 3-[1′-chloro-3′-(2″-phenyl-1″,3″-oxazol-5″-one=4″-ylidene)propen-1′-yl]coumarin towards some nucleophilic reagents

The chemical behaviours of 3-[1′-chloro-3′-(2″-phenyl-1″,3″-oxasol-5″-one-4″-ylidene)-propen-1′-yl]coumarin towards nucleophilic reagents (such as hydrolysis, aminolysis, hydroxyl-aminolysis, methanolysis and hydrazinolysis) were described.     

13C and 1H NMR investigation of the structure of N″-sulphonyl-N-alkylideneformamidrazones

The ¹³C and ¹H NMR spectra of N″-sulphonyl-N-alkylideneformamidrazones have been recorded and the chemical shifts assigned. The tautomeric structure proved to be an N²- alkylidenehydrazide sulphonylimide. The barrier to rotation around the CN¹ bond was estimated from variable from temperature ¹H NMR measurements, and the Z/E ratio and its solvent dependence was investigated.     

Complete assignment of the 1H and 13C NMR spectra of 4-methoxy-3′-methylsulfinyl-3,4′-diquinolinyl sulfides

The ¹H and ¹³C nmr spectra of 4-methoxy-3′-methylsulfinyl-3,4′-diquinolinyl sulfides 2, 3 and 4 were totally assigned using a combination of nmr techniques. As compared to the spectral data of sulfoxide 2 typical values of nitro group substituents effects in nitroquinolines 3 and 4 were observed. The H-2′ protons in sulfoxides 2, 3 and 4 are strongly influenced by ortho methylsulfinyl group and deshielded by about 0.7 ppm. PM3 method calculations support the structural conclusion that sulfinyl group oxygen points in direction of the positions 2′.     

The 1H NMR spectra of zinc complexes of pyridine-2-carbaldehyde 2′-pyridylhydrazone

Proton magnetic resonance spectra at 100 MHz are described for some zinc complexes of the E- and Z-isomers of pyridine-2-carbaldehyde 2′-pyridylhydrazone in d₆-dimethylsulphoxide solution. Chemical shift data are discussed qualitatively in relation to factors such as the charge on the metal ion, the anisotropy of ligand nitrogen atoms, electric field effects caused by the dipole moment of nitrogen lone pairs, metal-nonbonded-hydrogen interactions, ring current effects and the conformational changes undergone by each isomer on coordination.     

Michael addition polymerizations of difunctional amines (AA′) and triacrylamides (B3)

Novel hyperbranched poly(amido amine)s containing tertiary amines on the backbones and acryl or secondary amines as the surface groups were successfully synthesized via the Michael addition polymerizations of a triacrylamide [1,3,5‐triacryloylhexahydro‐1,3,5‐triazine (TT)] and a difunctional amine [n‐butylamine (BA)] NMR techniques were used to clarify the structures of hyperbranched polymers and polymerization mechanism. The reactivity of the secondary amine formed in situ was much lower than that of the primary amines in BA. When the feed molar ratio was 1:1 TT/BA, the secondary amine formed in situ was almost kept out of the reaction before the BA (AA′) and TT (B₃) monomers were consumed, and this led to the formation of A′B₂ intermediates containing one secondary amine group and two acryl groups. The self‐polymerization of the A′B₂ intermediates produced hyperbranched polymers bearing acryl as surface groups. For the polymerization with the feed molar ratio of 1:2 TT/BA, A′₂B intermediates containing one acryl group and two secondary amine groups were accumulated until self‐polymerization started; the self‐polymerization of the intermediates formed hyperbranched polymers with secondary amines as their surface groups. Modifications of surface functional groups were studied to form new hyperbranched polymers. The hyperbranched poly(amido amine)s were amorphous. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 6226–6242, 2006     

The complete analysis of the 1H NMR spectra of quinoline and two of its derivatives. sign determinations of inter-ring coupling constants by means of the INDOR technique

The complete ¹H NMR spectral analyses of quinoline and two of its derivatives (4,7-dichloroquinoline and 8-nitroquinoline) have been performed. All the long-range coupling constants were determined both in magnitude and sign. In determining the signs the INDOR technique was very useful and successful, allowing the resolution of transitions as close as a few hundredths of a Hz. The signs of the inter-ring coupling constants alternate with the number of intervening bonds, according to McConnell's rule, except the all-trans⁶J couplings. A linear relationship has been found between the ¹H?¹H and ¹⁹F?¹⁹F inter-ring coupling constants for which the spin polarization is transmitted almost exclusively via the π-electron system.     

Mass spectral fragmentation pattern of 3-(2′-hydroxyethyl)quinolin-2(1H)-one and its derivatives

Fragmentation patterns resulting from electron impact ionization of 3-(2′-hydroxyethyl)quinolin-2(1H)-one, three of its monosubstituted derivatives and four of its disubstituted derivatives were studied. The molecular ion of quinolinone-2-etbanol undergoes initial fragmentation with the loss of OH^·, H₂O, CO, ^·CHO, CH₂O, CH₂OH^·, CH₂?CHOH and HCNO species. The [M – CHO]⁺ ion is tentatively suggested to have been formed by the expulsion of H^· from the [M – CO]^+· ion and the [M - CHO]⁺ peak may be considered as diagnostic of a 2-quinolone-3-ethanol.     

Curing of epoxy resins with metal(II)4,4′,4″,4‴-tetraamino phthalocyanines-modification with elastomers

The use of metal phthalocyanine tetraamines in curing epoxy resins to form high-temperature-resistant matrix polymers for composites has been reported earlier. The effect of adding carboxy-terminated butadiene-acrylonitrile (CTBN) elastomer is now described; preliminary measurements of tensile, flexural, and short-beam shear strengths, dynamic moduli, resin content, and moisture absorption are presented, and the results of dynamic thermogravimetric analyses are given. In addition to their high char yield (86–87.5% at 800°C in a nitrogen atmosphere) and limiting oxygen index (48.3–50.3), the laminates showed good mechanical properties.