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1H and 13C Nuclear Magnetic Shielding in Gaseous and Liquid Propene

Kubiszewski M., Makulski W.

Polish Journal of Chemistry

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2008

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Vol. 82, nr 7

1457-1457

EN

Propylene, C3H6, was studied by high resolution NMR spectroscopy in liquid and gaseous state at 300 K. Extrapolation of gas-phase 1H and 13C chemical shifts to the ero-den sity limit permit ted the determinations of absolute nuclear magnetic shielding in the isolated propylene molecule. These new experimental results were used in a reliable verification of ab in itio calculations of proton and carbon nuclear magnetic shielding. The analogous pure liquid propylene spectra were also measured. The second virial coefficients and gas-to-liquid shifts were discussed in the context of intermolecular inter actions in gas and association in liquid phase.

2

Nuclear Magnetic Shielding and Indirect Spin-Spin Coupling Constants in Cyclopropane. Gaseous and Liquid NMR Measurements

Makulski W., Wilczek M.

Polish Journal of Chemistry

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2006

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Vol. 80, nr 7

1055-1060

EN

Cyclopropane (CH2)3 was studied by advanced methods of NMR spectroscopy in liquid and gaseous states at 300 K. Extrapolation of gas-phase chemical shifts to the zero-density limit allowed the determinations of 1H and 13C absolute nuclear magnetic shieldings of an isolated cyclopropane molecule. The indirect spin-spin coupling constants were extracted from experimental spectra and compared with the calculated values reported in the literature.

3

Influence of Intermolecular Interactions on Nuclear Magnetic Shielding Constans of OCS

Jackowski K., Les A., Makulski W., Wozniak K.

Polish Journal of Chemistry

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2002

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Vol. 76 / nr 4

575-580

EN

The gauge-included atomic orbital (GIAO) method has been applied within the coupled Hartree-Fock (CHF) approximation to compute 13C, 17Oand 33SNMRchemical shifts for solid OCS. Increasing clusters of OCS molecules taken out of crystal lattice have been used in an additive approximation to estimate the effect of intermolecular interactions on shielding of the carbon, oxygen and sulphur nuclei. There is a very good agreement achieved for NMR chemical shifts between the results of calculations and experimental measurements obtained for 13C and also some discrepancies for 17Oand 33S nuclei, probably due to deficiency of ab-initio calculations (lack of electron correlation). The results reveal that the 33S NMR signal of OCS is strongly dependent on intermolecular interactions.

4

Effects of intermolecular interactions on the 1H, 13C and 14N NMR chemical shifts of N,N-Dimethylformamide dissolved in monosubstituted benzenes

Jackowski K., Makulski W., Trenkner-Olejniczak Z.

Bulletin of the Polish Academy of Sciences. Chemistry

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2000

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Vol. 48, No. 1

81-89

EN

1 H,13 C and 14 N NMR chemical shifts have been used to monitor the dilution process of JV,7V-dimethylformamide (DMF) in monosubstituted benzenes. Both the proton and carbon chemical shifts of non-equivalent methyl groups in DMF are spectacularly influenced by ASIS (Aromatic Solvent Induced Shift) effects at the low concentration of a solute. On the other hand, the destruction of DMF liquid structure itself is better seen when the 13C chemical shift of a carbonyl carbon and the 14N shift are verified. A good correlation between the latter NMR chemical shifts has been found. It is shown on the basis of GIAO-CHF model calculations that the destruction of solute dipole-dipole dimers may be responsible for the increase of carbonyl carbon and nitrogen shielding constants of DMF in solvents.