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

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.

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

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19870453 ◽

1987 ◽

Vol 52 (2) ◽

pp. 453-475 ◽

Cited By ~ 8

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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Oxygen-17 NMR Study of the Uranyl Ion. IV.17O Nuclear Magnetic Relaxation and Chemical Shifts of Uranyl Oxygen Atoms and Coordinated Water

Bulletin of the Chemical Society of Japan ◽

10.1246/bcsj.60.489 ◽

1987 ◽

Vol 60 (2) ◽

pp. 489-492 ◽

Cited By ~ 6

Author(s):

Woo-Sik Jung ◽

Hiroshi Tomiyasu ◽

Hiroshi Fukutomi

Keyword(s):

Magnetic Relaxation ◽

Chemical Shifts ◽

Nuclear Magnetic Relaxation ◽

Uranyl Ion ◽

Nmr Study ◽

Coordinated Water ◽

Nuclear Magnetic ◽

Oxygen Atoms

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Preparation and characterization of some ruthenium(II) porphyrins containing tertiary phosphine axial ligands, including the crystal structure of (octaethylporphinato)bis(triphenylphosphine)ruthenium(II)

Canadian Journal of Chemistry ◽

10.1139/v84-127 ◽

1984 ◽

Vol 62 (4) ◽

pp. 755-762 ◽

Cited By ~ 20

Author(s):

Sara Ariel ◽

David Dolphin ◽

George Domazetis ◽

Brian R. James ◽

Tak W. Leung ◽

...

Keyword(s):

Crystal Structure ◽

Phosphine Ligands ◽

Tertiary Phosphine ◽

X Ray ◽

Porphyrin Complex ◽

H Nmr ◽

Axial Ligands ◽

Nmr Data ◽

Phosphine Complex

The ruthenium(II) porphyrin complex Ru(OEP)(PPh3)2 (OEP = the dianion of octaethylporphyrin) has been prepared from Ru(OEP)(CO)EtOH, and the X-ray crystal structure determined; as expected, the six-coordinate ruthenium is situated in the porphyrin plane and has two axial phosphine ligands. Synthesized also from the carbonyl(ethanol) precursors were the corresponding tris(p-methoxyphenyl)phosphine complex, and the Ru(TPP)L2 (TPP = the dianion of tetraphenylporphyrin, L = PPh3, P(p-CH3OC6H4)3, P″Bu3) and Ru(TPP)(CO)PPh3 complexes. Optical and 1H nmr data are presented for the complexes in solution. In some cases dissociation of a phosphine ligand to generate five-coordinate species occurs and this has been studied quantitatively in toluene at 20 °C for the Ru(OEP)L2 and Ru(TPP)L2 systems.

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Synthesis, Characterization of La(III), Nd(III), and Er(III) Complexes with Schiff Bases Derived from Benzopyran-4-one and Thier Fluorescence Study

International Journal of Inorganic Chemistry ◽

10.1155/2012/901415 ◽

2012 ◽

Vol 2012 ◽

pp. 1-13 ◽

Cited By ~ 12

Author(s):

Aida L. El-Ansary ◽

Nora S. Abdel-Kader

Keyword(s):

Schiff Bases ◽

Molar Conductance ◽

Spectral Studies ◽

Water Molecules ◽

Stoichiometric Ratio ◽

Binuclear Complexes ◽

Fluorescence Study ◽

H Nmr ◽

Coordinated Water

The Schiff bases, L1, L2, and L3, are synthesized from the condensation of 5,7-dihydroxy-6-formyl-2-methylbenzopyran-4-one (L) with 2-aminopyridine (1), p-phenylenediamine (2), and o-phenylenediamine (3). The prepared Schiff bases react with lanthanum (III), neodymium (III), and erbium (III) nitrate to give complexes with stoichiometric ratio (1 : 1) (ligand : metal). The binuclear complexes of Er(III) with L3 and the three metal ions with L2 are separated. The complexes have been characterized by elemental analysis, molar conductance, electronic absorption, and infrared, 1H-NMR spectral studies. The presence of hydrated and coordinated water molecules is inferred from thermogravimetric analysis. Thermal degradation studies show that the final product is the metal oxide. The luminescence properties of the Nd(III) and Er(III) complexes in dimethylformamide (DMF) solutions were investigated.

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Spectroscopic and X-Ray Investigation of Cobalt(III) Complexes with 2-Oximinocarboxylic Acids

Zeitschrift für Naturforschung B ◽

10.1515/znb-1993-0403 ◽

1993 ◽

Vol 48 (4) ◽

pp. 409-417 ◽

Cited By ~ 10

Author(s):

Rostislav D. Lampeka ◽

Zamira D. Uzakbergenova ◽

Victor V. Skopenko

Keyword(s):

Electronic Absorption Spectra ◽

Molecular Structures ◽

X Ray Diffraction ◽

Octahedral Structure ◽

Space Group ◽

X Ray ◽

H Nmr ◽

Nmr Data ◽

R Factors

Mixed complexes of Co(III) with 2-oximinopropionic (H2A) or 2-oximino-3-phenylpropionic (H2B) acid and different amine (imidazole, benzimidazole, pyridine, β-picoline, γ-picoline) are reported. Characterization of the complexes was based upon elemental analysis, conductivity and JR, 1H NMR, and electronic absorption spectra, and X-ray diffraction analysis. The organic ligands behave as O,N donors via the carboxyl oxygen and the oxime nitrogen atoms. A trans-octahedral structure has been assigned to the bis(2-oximinocarboxylato)bis(amine)cobalt(III) on the basis of 1H NMR data.The crystal and molecular structures of the complexes trans-[bis(2-oximinopropionato)bis-(imidazole)]- (I) and trans-[bis(2-oximinopropionato)bis(pyridine)]cobalt(III) (II) were determined. I crystallizes in space group P2/n with a = 14.1 67(2), b = 8.774(1), c = 14.785(2) Å,β = 113.37(1)°, Z = 4, Dcalc = 1.568 g · cm-3. II crystallizes in space group P1̄ with a = 9.122(2), b = 10.038(2), c = 11.759(2) Å, α = 69.95(1)°, β = 67.47(2)°, γ = 69.49(2)°, Ζ = 2, Dcalc = 1.547 g cm-3. The structures were refined to unweighted R factors of 0.036 and 0.028, respectively. The coordination sphere around Co is pseudo-octahedral with the 2-oximinopropionato ligands occupying four equatorial positions, and the amines in axial positions.

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1H NMR studies on the solution conformation of the [L-Ser10] and [D-Ser10] analogues of contulakin-G

Canadian Journal of Chemistry ◽

10.1139/v04-176 ◽

2005 ◽

Vol 83 (2) ◽

pp. 156-165 ◽

Cited By ~ 2

Author(s):

Lill Kindahl ◽

Lennart Kenne ◽

Corine Sandström

Keyword(s):

Hydrogen Bond ◽

Biological Data ◽

Random Coil ◽

Solution Conformation ◽

Nmr Studies ◽

Peptide Backbone ◽

H Nmr ◽

Nmr Data ◽

Nmr Study ◽

C Terminus

The synthesis of the O-glycosylated serine-10 analogue of contulakin-G yielded both the [L-] and the [D-Ser10] analogues. The 1H NMR study indicated that the sugars of the two Ser10-glycosylated peptides lacked the hydrogen bond to the peptide backbone that exists in contulakin-G. NOEs showed that the glycan part of the [D-Ser10] analogue had a different orientation to the peptide backbone than that of the [L-Ser10] analogue. The peptide backbones in the two compounds were found to exist mainly in random coil conformations, with transient turns at the site of glycosylation. A transient turn was also found at the C-terminus of the [D-Ser10] glycopeptide. The NMR data indicated that the average conformation of the [D-Ser10] analogue resembles the conformation of contulakin-G more than the [L-Ser] does. Since biological data showed that the [D-Ser10] glycopeptide was as active as contulakin-G, while the [L-Ser10] glycopeptide was only slightly active at more than 100 times the dose, it is possible that it is the orientation of the glycan relative to the peptide chain that is actually recognized by the proteolytic enzyme.Key words: conformation, contulakin-G analogues, NMR, O-linked glycopeptide.

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A multinuclear NMR study of some cyclic phosphonic diamides

Spectroscopy An International Journal ◽

10.1155/1994/683476 ◽

1994 ◽

Vol 12 (1) ◽

pp. 31-34

Author(s):

Wojciech Bocian ◽

Lech Stefaniak ◽

Graham A. Webb

Keyword(s):

Molecular Structure ◽

Chemical Shifts ◽

Multinuclear Nmr ◽

Nmr Data ◽

Nmr Study ◽

Sensitive Parameters

1H,13C,15N and31p NMR data are presented for four cyclic phosphonic diamides. In tenns of useful structural infonnation it is found that the31p chemical shifts and1J(31P_15N) couplings are the most sensitive parameters to variations in molecular structure.

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Synthesis and characterization of several series of 4-acyl-1-[2-aryl-1-diazenyl]piperazines

Canadian Journal of Chemistry ◽

10.1139/cjc-2014-0242 ◽

2014 ◽

Vol 92 (9) ◽

pp. 838-848 ◽

Cited By ~ 1

Author(s):

Vanessa Renee Little ◽

Keith Vaughan

Keyword(s):

High Resolution ◽

Ir Spectroscopy ◽

Chemical Shifts ◽

Synthesis And Characterization ◽

Model Compounds ◽

Primary Aromatic Amine ◽

Piperazine Ring ◽

H Nmr ◽

C Nmr

Five series of a novel class of 4-acyl-1-[2-aryl-1-diazenyl]piperazines have been synthesized and characterized: the 4-acetyl-1-[2-aryl-1-diazenyl]piperazines [series 1]; the 4-cyclohexylcarbonyl-1-[2-aryl-1-diazenyl]piperazines [series 2]; the 4-benzoyl-1-[2-aryl-1-diazenyl]piperazines [series 3]; the benzyl 4-[2-aryl-1-diazenyl]-1-piperazinecarboxylates [series 4]; and the t-butyl 4-[2-aryl-1-diazenyl]-1-piperazinecarboxylates [series 5]. The compounds were synthesized by diazotization of a primary aromatic amine and subsequent coupling to an appropriate secondary amine: 1-acetylpiperazine [series 1]; 1-(cyclohexylcarbonyl)-piperaizine [series 2]; 1-benzoylpiperazine [series 3]; benzyl 1-piperazinecarboxylate [series 4]; and t-butyl piperazine-1-carboxylate (1-BOC-piperazine) [series 5]. The compounds of series 1–5 were characterized by 1H NMR, 13C NMR, high-resolution MS and IR spectroscopy. The model compounds 1,4-di[2-aryl-1-diazenyl]piperazines, and ethyl 4-[2-aryl-1-diazenyl]-1-piperazinecarboxylates were used to facilitate the assignment of the chemical shifts specific to the piperazine ring carbons. HSQC spectra of select compounds established the correlation between proton and carbon resonance signals.

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Ab initio and 1H NMR study of the Zn(II) complexes of a nido- and a closo-carboranylporphyrin

Journal of Porphyrins and Phthalocyanines ◽

10.1142/s1088424604000362 ◽

2004 ◽

Vol 08 (07) ◽

pp. 996-1006 ◽

Cited By ~ 4

Author(s):

Petia Bobadova-Parvanova ◽

Yuko Oku ◽

Anura Wickramasinghe ◽

Randall W. Hall ◽

M. Graça H. Vicente

Keyword(s):

Ab Initio ◽

Complex Mixture ◽

Neutron Capture Therapy ◽

Ab Initio Study ◽

Hydrogen Atoms ◽

Pyridine Ligand ◽

H Nmr ◽

Boron Neutron Capture ◽

Nmr Data ◽

Nmr Study

An ab initio study of a promising nido-carboranylporphyrin for the boron neutron capture therapy of tumors, and of its closo precursor is reported. Base-induced deboronation of neutral ZnDCP , believed to exist as a mixture of 3 stereoisomers, produces the tetraanionic ZnDCP 4- as a complex mixture of isomers. 1 H NMR data and ab initio calculations support these findings. The position of the axial pyridine ligand in ZnDCP 4- and the orientation of the endo hydrogen atoms on the open faces of the nido-carborane cages significantly influence the total energy of the ZnDCP 4- structures. It is suggested that the "cocktail" of isomers possibly enhances the biological activity of tetra(nido-carboranyl)porphyrins, such as ZnDCP 4-.

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