Oxygen Isotope Effects in <sup>55</sup>Mn and <sup>95</sup>Mo NMR Spectra of the Permanganate and Molybdate Ion

Buckler, K. U.; Haase, Anton; Lutz, O.; Müller, M.; Nolle, A.

doi:10.1515/zna-1977-0204

Cited by 26 publications

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“…Inserting the corresponding masses of the isotopic pairs 160, 180 and 32S, 34S this expression yields a value of 2.7 for the ratio of the isotopic effects in oxo-and in thiomolybdate. Hence the sulfur induced isotope effect of 95M0 agrees fairly well with values predicted by the theory of Lauterbur [10] from the known isotope effect due to oxygen [5]. Intramolecular isotopic effects on the Larmor frequency induced by isotopic nuclei heavier than carbon have been observed only in some favourable cases.…”

Section: Methodssupporting

confidence: 84%

“…The same shift has also been observed in a 0.25 molal solution of (NHg)zMoS 4 in D20. For the corresponding oxo species Mu-16'~tJ4_n18t~z-kjn (n = 0, 1, 2, 3, 4) an intramolecular isotope effect of (0.25 _+0.01)ppm to lower frequency has been found per each replaced 160 [5]. These mass dependent isotope effects can be treated by using different vibrational energies in the ground and excited electronic states for the diverse isotopic species [10].…”

Section: Methodsmentioning

confidence: 99%

“…it is known, that the replacement of one x6 0 atom by 180 results in an isotopic effect of the chemical shift of -(0.25_+ 0.01) ppm [5]. Since the linewidth of 95Mo in tetrathiomolybdate is very small [4], it is interesting whether a sulfur induced intramolecular isotope effect in MoS 2-is also observable.…”

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Sulfur isotope effect on95Mo nuclear magnetic shielding in MoS 4 2?

1977

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Section: Methodssupporting

confidence: 84%

Section: Methodsmentioning

confidence: 99%

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Sulfur isotope effect on95Mo nuclear magnetic shielding in MoS 4 2?

1977

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“…[8,9,13]). For 95 Mo in Mo04 2~ -for these molecules to our knowledge no experimental values of the vibrational energies are known -also lower Larmor frequencies were observed [9,10] for the species containing heavier isotopes.For the P04 3~i on the vibrational energies are known to be higher in aqueous solutions for the P 18 04 3~ than for the P 16 04 3~ (Ref. [14]).…”

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confidence: 99%

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Oxygen Isotope Effect on ³¹P NMR Spectra in the Phosphate Ion

Lutz

Nolle

Staschewski

1978

Zeitschrift Für Naturforschung A

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By Fourier transform high resolution NMR spectroscopy the 31 P signals of the phosphate species 31 P 16 04 _ t! 18 Ow 3_ " (n = 0, 1, 2, 3, 4) have been resolved in aqueous solutions of potassium phosphate. An isotope effect on the Larmor frequency of <5 ( 31 P) = (0.019 ± 0.002) to lower frequency was found for the substitution of a 18 0 atom for a 16 0 atom in the phosphate ion.It is well known, that in a molecule the substitution of a certain isotope for another influences the molecular properties. For many molecules changes in the Larmor frequencies have been observed if isotopes are substituted (see f. e. Ref.[1]). By increasing the resolution of the NMR spectra such isotope effects of the chemical shift can be measured even if the mass differences of the different isotopes are small such as for 16 0 and 18 0 or 32 S and 34 S (Ref. [2 -11]). For some central nuclei in oxyanions oxygen induced isotope effects have been found [8, 9,].Following the theory of Benedek et al. (Ref. [12]) Lauterbur [6] derived a simple relation, which describes the observed oxygen induced isotope effects in oxyanions fairly well [9, 10,]. In this theory the isotope effect of the chemical shift depends on the vibrational energies of the respective molecule. The theory predicts a lower Larmor frequency, if in the molecule with the heavier isotope the vibrational energies are smaller than in the molecule with the lighter one. This correlation is veryfied for example in the case of 55 Mn in Mn04~ (Ref. [8,9,13]). For 95 Mo in Mo04 2~ -for these molecules to our knowledge no experimental values of the vibrational energies are known -also lower Larmor frequencies were observed [9,10] for the species containing heavier isotopes.For the P04 3~i on the vibrational energies are known to be higher in aqueous solutions for the P 18 04 3~ than for the P 16 04 3~ (Ref. [14]). This is an anomalous behaviour [15] and has been explained by an isotope effect of hydrogen bonding in the solution, as in solid samples normal vibrational energies are measured [16]. It is interesting to know first, whether an isotope effect of the chemical shift of 31 P for the phosphate species P 10 O4 3-and P 18 04 3~ is observable at all and second, whether a lower Larmor frequency for the phosphate species containing heavier oxygen isotopes is found in spite of the anomalous vibrational energies or not. Measurements about this problem are reported in the following. ExperimentalThe 31 P NMR signal was observed with a Bruker SXP 4-100 MHz spectrometer in a magnetic field of 2.11 T at 36.44 MHz. The magnetic field was internally stabilized by the 2 H lock B-SN 20. The free induction decays were accumulated and Fourier transformed by a B-NC 12 computer.Solid P205 with the natural abundance of 18 0 was dissolved in high-grade H2 18 0. The solution was concentrated by vacuum distillation until a syrup of phosphoric and diphosphoric acid remained which was rediluted by a bigger quantity of 99% H2 18 0. Sealed off in an ampoule the solution now was heated at 120 c C for 24 h...

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Deuterium isotope effects and bonding in carbonylvanadium complexes

Rehder

Hoch

Jameson

1990

Magnetic Reson in Chemistry

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The effects of one-bond and two-bond *H, 13C0 and C'*O isotope shifts on "V shielding in various carbonyl-Cp vanadium complexes (Cp = $cyclopentadienyl) are reported and discussed with respect to the sensitivity of 5'V shifts to bond extensions, and the rovibrationally averaged values of such bond extensions. These isotope effects provide some insight into the bonding situation in these complexes. It is shown that the rate-determining step in the reaction between V(CO), and C,H,D, which leads to CpV(CO),, is not subject to a kinetic isotope effect. The deuterium solvent isotope effects on "V shielding in p(CO),l-and [VO,l3-are also investigated.

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Oxygen Isotope Effects in ⁵⁵Mn and ⁹⁵Mo NMR Spectra of the Permanganate and Molybdate Ion

Abstract: By Fourier transform NMR spectroscopy the

Cited by 26 publications

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Sulfur isotope effect on95Mo nuclear magnetic shielding in MoS 4 2?

Sulfur isotope effect on95Mo nuclear magnetic shielding in MoS 4 2?

Oxygen Isotope Effect on ³¹P NMR Spectra in the Phosphate Ion

Deuterium isotope effects and bonding in carbonylvanadium complexes

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Oxygen Isotope Effects in 55Mn and 95Mo NMR Spectra of the Permanganate and Molybdate Ion

Abstract: By Fourier transform NMR spectroscopy the

Cited by 26 publications

References 0 publications

Sulfur isotope effect on95Mo nuclear magnetic shielding in MoS 4 2?

Sulfur isotope effect on95Mo nuclear magnetic shielding in MoS 4 2?

Oxygen Isotope Effect on 31P NMR Spectra in the Phosphate Ion

Deuterium isotope effects and bonding in carbonylvanadium complexes

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Oxygen Isotope Effects in ⁵⁵Mn and ⁹⁵Mo NMR Spectra of the Permanganate and Molybdate Ion

Oxygen Isotope Effect on ³¹P NMR Spectra in the Phosphate Ion