The 51V NMR Spectra of Some Oxo-, Peroxo-, Nitrosyl- and Hydroxylamidovanadium Complexes

1981 ◽  
Vol 36 (10) ◽  
pp. 1251-1254 ◽  
Author(s):  
Dieter Rehder ◽  
Karl Wieghardt
Keyword(s):  
Correlation Time ◽  
Nmr Spectra ◽  
Dinuclear Complexes ◽  
Chelate Complexes ◽  
Factors Associated ◽  
51V Nmr ◽  
Molecular Correlation ◽  
Steric Factors ◽  
Line Widths ◽  
Nmr Signals

Abstract The 51V NMR spectra are recorded for 3 dinuclear complexes {VO(ONR2)2μ - O and 13 mononuclear vanadium (+ V) and (+III) chelate complexes of the general formula [VXYZ]q, where X = O2-, NO-; Y = O2-, O22-, R2NO-; and Z = picolinate-(pic), dipicolinate2- (dipic), nitrilo-tri(2-propanolate)3-, and o-phenanthroline (phen). Shielding of the 51V nucleus increases as O2- is replaced for NO-, and in the series (O2- + dipic) < (2 O22- + pic) < (R2NO- + dipic) < (2 H2NO- + phen) < (2 H2NO- + pic); Et2NO- < H(Me)NO- < H2NO-; and (dinuclear complexes) C5H10NO- < Bz2NO- < Et2NO- These trends are explained on the basis of variations of molecular parameters correlated to electronic and steric factors associated with the ligands. Line widths of the 51V NMR signals are discussed in terms of influences originating from variations of the electric field gradient and the molecular correlation time

Nuclear Quadrupole Perturbations in 51V NMR Spectra of Oxovanadium(+V) Complexes

1982 ◽  
Vol 37 (2) ◽  
pp. 139-149 ◽  
Author(s):  
Kurt Paulsen ◽  
Dieter Rehder
Keyword(s):  
Asymmetry Parameter ◽  
Nmr Spectra ◽  
Electric Quadrupole ◽  
Coupling Constants ◽  
Concentration Effects ◽  
Quadrupole Coupling ◽  
Line Widths ◽  
Nuclear Quadrupole ◽  
Nmr Signals ◽  
Temperature And Concentration Effects

Abstract Nuclear electric quadrupole coupling constants e2qQ/h have been obtained by evaluation of quadrupole perturbations in 51V NMR spectra of various vanadyl esters and esterchlorides of the general formula VOCl3-n(OR)n (n=0-3; R = Me, Prn , Prn, Bun and Bui). e2qQ/h values have been calculated from (i) 2nd. order quadrupole splittings of the 51V NMR signals in pseudo-polycrastalline samples, (ii) 1st. order quadrupole splittings in nematic liquid crystals and (iii) line widths A ⊿ν1/2 of the 51V and 35Cl NMR signals in the liquid isotropic state and e2qQ/h(35Cl) obtained by pure NQR measurements. The influences of the asymmetry parameter η and the orientation of the crystallites in powder spectra are considered, and temperature and concentration effects upon ⊿ν1/2 and 51V shielding (isotropic phases) and the ordering factor Sa (meso-phases) are discussed.

Carbon-13 and nitrogen-14 NMR spectra of 1-(substituted phenyl)pyridinium salts

1980 ◽  
Vol 45 (10) ◽  
pp. 2766-2771 ◽  
Author(s):  
Antonín Lyčka
Keyword(s):  
Heavy Water ◽  
Nmr Spectra ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Pyridinium Salts ◽  
Nmr Signals ◽  
C Nmr

The 13C and 14N NMR spectra of 1M solutions of 1-(substituted phenyl)pyridinium salts (4-CH3, 4-OCH3, H, 4-Cl, 4-Br, 4-I, 3-NO2, 4-NO2, 2,4-(NO2)2 (the 13C NMR only)) have been measured in heavy water at 30 °C. The 13C and 14N chemical shifts, the 1J(CH) coupling constants, some 3J(CH) coupling constants, and values of half-widths Δ 1/2 of the 14N NMR signals are given. The 13C chemical shifts of C(4) correlate with the σ0 constants (δC(4) = (1.79 ± 0.097) σ0 + (147.67 ± 0.041)), whereas no correlation of the nitrogen chemical shifts with the σ constants has been found. The half-widths Δ 1/2 correlate with the σ0 constants (Δ 1/2 = (76.2 ± 4.9) σ0 + (106.4 ± 2.2)) except for 1-phenylpyridinium chloride.

Line widths, sensitivity and artifacts in33S NMR Spectra: The case of aqueous sulphides

1986 ◽  
Vol 24 (11) ◽  
pp. 1004-1007 ◽  
Author(s):  
P. S. Belton ◽  
I. J. Cox ◽  
R. K. Harris
Keyword(s):  
Nmr Spectra ◽  
Line Widths

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.

Determination of chemical shift anisotropy tensor and molecular correlation time of proton pump inhibitor omeprazole by solid state NMR measurements

2020 ◽  
Vol 44 (44) ◽  
pp. 19393-19403
Author(s):  
Krishna Kishor Dey ◽  
Manasi Ghosh
Keyword(s):  
Correlation Time ◽  
Chemical Shift Anisotropy ◽  
Lattice Relaxation ◽  
Lattice Relaxation Time ◽  
Spin Lattice Relaxation ◽  
Spin Lattice ◽  
Structure And Dynamics ◽  
Molecular Correlation ◽  
Anisotropy Tensor

The correlation between the structure and dynamics of omeprazole is portrayed by extracting CSA parameters through the 13C 2DPASS CP-MAS SSNMR experiment, site specific spin–lattice relaxation time by Torchia CP experiment, and calculation of the molecular correlation time.

scholarly journals Propionate stimulates pyruvate oxidation in the presence of acetate

2014 ◽  
Vol 307 (8) ◽  
pp. H1134-H1141 ◽  
Author(s):  
Colin Purmal ◽  
Blanka Kucejova ◽  
A. Dean Sherry ◽  
Shawn C. Burgess ◽  
Craig. R. Malloy ◽  
...  
Keyword(s):  
Pyruvate Dehydrogenase ◽  
Energy Production ◽  
Nmr Spectra ◽  
Heart Tissue ◽  
Viable Myocardium ◽  
Normal Heart ◽  
Alternative Substrate ◽  
Isotopomer Analysis ◽  
Nmr Signals ◽  
C Nmr

Flux through pyruvate dehydrogenase (PDH) in the heart may be reduced by various forms of injury to the myocardium, or by oxidation of alternative substrates in normal heart tissue. It is important to distinguish these two mechanisms because imaging of flux through PDH based on the appearance of hyperpolarized (HP) [13C]bicarbonate derived from HP [1-13C]pyruvate has been proposed as a method for identifying viable myocardium. The efficacy of propionate for increasing PDH flux in the setting of PDH inhibition by an alternative substrate was studied using isotopomer analysis paired with exams using HP [1-13C]pyruvate. Hearts from C57/bl6 mice were supplied with acetate (2 mM) and glucose (8.25 mM). 13C NMR spectra were acquired in a cryogenically cooled probe at 14.1 Tesla. After addition of hyperpolarized [1-13C]pyruvate, 13C NMR signals from lactate, alanine, malate, and aspartate were easily detected, in addition to small signals from bicarbonate and CO2. The addition of propionate (2 mM) increased appearance of HP [13C]bicarbonate >30-fold without change in O2 consumption. Isotopomer analysis of extracts from the freeze-clamped hearts indicated that acetate was the preferred substrate for energy production, glucose contribution to energy production was minimal, and anaplerosis was stimulated in the presence of propionate. Under conditions where production of acetyl-CoA is dominated by the availability of an alternative substrate, acetate, propionate markedly stimulated PDH flux as detected by the appearance of hyperpolarized [13C]bicarbonate from metabolism of hyperpolarized [1-13C]pyruvate.

scholarly journals Trifluoroacetylation of Alcohols During NMR Study of Compounds with Bicyclo[2.2.1]heptane, Oxabicyclo[3.3.0]octane and Bicyclo[3.3.0]octane Skeleton

2021 ◽  
Vol 72 (2) ◽  
pp. 156-177
Author(s):  
Constantin I. Tanase ◽  
Anamaria Hanganu ◽  
Constantin Draghici
Keyword(s):  
Nmr Spectra ◽  
Cyclopropane Ring ◽  
Secondary Alcohol ◽  
Primary Alcohol ◽  
1H And 13C Nmr ◽  
Alcohol Group ◽  
Nmr Study ◽  
Group A ◽  
Graphical Presentation ◽  
Nmr Signals

TFA was added to a solution of a bicyclo[2.2.1]heptane azide-alcohol in CDCl3 to correctly characterize the compound, but during 24 h gave the trifluoro acetylated compound in quantitative yield. NMR spectra of the esterified compound helped us also to correctly attribute the NMR signals to the protons, and also confirmed the identification of the carbon atoms. The study was extended to other 14 compounds containing a primary alcohol group alone or with an ethylene ketal, a δ- or -lactone group, a primary and a secondary group, two primary and an alkene group and two primary and a secondary alcohol groups on scaffolds containing bicyclo[2.2.1]heptane, oxabicyclo[3.3.0]octane, bicyclo [2.2.1]heptane constrained with a cyclopropane ring and bicyclo[3.3.0]octane fragments. The esterification of all compounds was also quantitative in 24 to 72 h; this helped us to correct attribute the NMR signals to the protons and carbon atoms of the un-esterified compounds by comparison with those of the trifluoro acetylated compounds. A graphical presentation of 1H- and 13C-NMR spectra of a few un-esterified and esterified compounds are presented in the paper.

Temperature and Solvent Dependence of Vanadium-51 Chemical Shifts and Line Widths of Vanadyl-triisopropylate

1978 ◽  
Vol 33 (7) ◽  
pp. 834-839 ◽  
Author(s):  
Kurt Paulsen ◽  
Dieter Rehder ◽  
Detlef Thoennes
Keyword(s):  
Chemical Shifts ◽  
Exchange Interactions ◽  
Molecular Symmetry ◽  
Satellite Line ◽  
Monomeric Species ◽  
Upfield Shift ◽  
Molecular Correlation ◽  
Solvent Dependence ◽  
Line Widths ◽  
Main Factor

Line widths ⊿ν1/2 of 51V n.m.r. signals of vanadyl-triisopropylate VO(OPri)3 dissolved in tetrahydrofurane range from 10 to 610 Hz, increasing with decreasing temperature according to a theoretically proposed T-1/2 exp (E/RT) law, indicating that the molecular correlation time τc is the main factor influencing line widths in this system. With lowering of temperature, 51V-shielding decreases (the temperature gradient of the chemical shift δV is about - 0.5 ppm/K over a temperature range of 300-180 K), suggesting a loss of molecular symmetry due to solvation and association processes. In pentane, methylcyclohexane and diethylether, the δV/T and ⊿ν1/2/T correlations exhibit two inconsistencies at approximately 190 and 240 K which are attributed to the formation of clusters, and of oligomers {VO(OPri)3}n, respectively. The latter gives rise to a satellite line with an upfield shift relative to the monomeric species. Exchange interactions are discussed as a second factor affecting line widths.

(Cyclopentadienyl)dihalogenochromium-Donor Compounds. Synthesis and NMR Investigation

1995 ◽  
Vol 50 (11) ◽  
pp. 1739-1747 ◽  
Author(s):  
Brigitte Bräunlein ◽  
Frank H. Köhler ◽  
Werner Strauß ◽  
Harald Zeh
Keyword(s):  
Dynamic Behavior ◽  
Spin Density ◽  
Nmr Spectra ◽  
Rapid Identification ◽  
Spin Transfer ◽  
H Nmr ◽  
Electronegative Substituent ◽  
Intramolecular Dynamic ◽  
Nmr Signals

A series of paramagnetic (S = 3/2) chromium half-sandwiches of the type CpCrX2D (D = donor) were synthesized by starting from [CpCrX2]2, Cp2Cr, CpCrCl2(THF), and Cp*Cr(CH3)2[P(CH3)3]. Besides the parent cyclopentadienyl (Cp) the alkylated derivatives CH3C5H4, (CH3)5C5 (Cp*), and C2H5(CH3)4C5 were bound to chromium. The electronegative substituent was X = F, Cl, Br, I, and triflate, while the donors were three ethers, four ketones, dimethylsulfoxide, acetonitrile, methylisocyanide, pyridine, and seven molecules ER3 where E = N, P, As, Sb. The half-sandwiches were partly isolated and partly established in solution. The 13C and 1H NMR spectra showed strongly shifted signals which allowed to quantitatively investigate the equilibrium between CpCrX2D and the anti ferromagnetic species [CpCrX2]2. The NMR signals of CpCrX2D and its substituted derivatives appeared in characteristic ranges thus providing a means of rapid identification. Considerable spin density was found to be induced on the ligands; it is negative in the Cp π system. As for the donors, inter- and intramolecular dynamic behavior as well as selective spin transfer to the γ protons of acetonitrile, methylisocyanide, and ketones was detected.

Koordinationschemie π-gebundener Cyclopentadienyl-Chalcogeno-Ether, II. Palladium(II)- und Platin(II)-Komplexe von [C5(SMe)5]Mn(CO)3, [C5Cl2(SMe)3]Mn(CO)3 und [C5Cl2(SMe)2(PPh2)]Mn(CO)3./ Coordination Chemistry of π-Bonded Cyclopentadienyl Chalcogeno Ethers, II. Palladium(II) and Platinum(II) Complexes of [C5(SMe)5]Mn(CO)3, [C5Cl2(SMe)3]Mn(CO)3 and [C5Cl2(SMe)2(PPh2)]Mn(CO)3

1995 ◽  
Vol 50 (9) ◽  
pp. 1307-1318 ◽  
Author(s):  
Karlheinz Sünkel ◽  
Adrian Blum
Keyword(s):  
Coordination Chemistry ◽  
Crystal Structures ◽  
Nmr Spectra ◽  
Chelate Complexes ◽  
H Nmr ◽  
Pt Complex ◽  
Meso Form

AbstractTreatment of the cymantrene thioether [C5(SMe)5]Mn(CO)3 (IIb) with Na2PdCl4 or K2PtCl4 yields the bimetallic chelate complexes [C5(SMe)5]Mn(CO)3*MCl2 (M = Pd (2) or Pt (3)). Similarly, the S,P-chelate complexes [C5Cl2(SR)2(PPh2)]Mn(CO)3*PdCl2 (R = Me (4a), Ph (4b)) can be obtained from the corresponding mononuclear cymantrene derivatives and Na2PdCl4 or (PhCN)2PdCl2. Analysis of the 1H NMR spectra only allows for the Pt complex the identification of one meso form, which seems to be favoured by 2:1, together with the D,L forms. The crystal structures of [C5Cl2(SMe)3]Mn(CO)3*PdCl2(1, C11H9Cl4MnO3PdS3, triclinic, P1̄, a = 7.617(3) Å , b = 10.528(4) Å ,c = 12.473(5) Å , α = 72.95(3)°, β = 84.94(3)°, γ = 88.75(3)°, V = 952.6(6) Å3, Z = 2), 2 (C13H15Cl2MnO3PdS5, orthorhombic, Pn21/c, a = 12.739(5) Å , b = 9.992(3) Å , c = 16.884(5) Å , V = 2149(1) Å, Z = 4), and 4 (C23H18Cl6MnO3PPdS2, monoclinic, P21/c, a = 13.199(4) Å , b = 29.198(11) Å , c = 15.921(7) , β - 101.41(3)°, V = 6015(4) Å3, Z = 8) are reported and compared with each other and other bimetallic metallocene phosphine and thioether derivatives.

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