A gain in detection sensitivity of more than 3 orders of magnitude has been achieved in high-resolution solid-state 13C NMR of monocrystalline fluorene doped with acridine by applying optical nuclear polarization (ONP) via excited triplet states to protons and transferring this proton polarization to the 13C nuclei. This sensitivity gain was utilized to measure the angular dependence (rotation pattern) of the 13C NMR lines. In this way the principal values and orientations of all 13C chemical shielding tensors were determined. While the 13C shielding tensor of the bridging methylene group exhibits only a small anisotropy, at the aromatic carbon positions the typical strong anisotropy is observed. All tensors belonging to the same molecule have one principal axis, perpendicular to the molecular plane, in common, showing that in the crystal lattice the fluorene molecule is in a planar configuration. The experimental data are compared to ab initio calculations employing optimized geometries and gauge included atomic orbitals density functional theory (GIAO DFT). The orientations of all calculated tensors are in excellent agreement with the experimental data. On an absolute scale the calculated shielding parameters reproduce the experimental values reasonably well. A significant improvement of the calculated eigenvalues is achieved by shifting the tensors employing data from calculations of benzene and methane.

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Multinuclear magnetic resonance isotropic nuclear shieldings and their principal components for α‐ and β‐glucose and several related compounds were calculated at the DFT/6–31+G* level of theory using the B3PW91 density functional. The absolute values were converted to chemical shifts and compared with experiment. A good performance of the DFT method in the prediction of the GIAO NMR parameters for simple sugars was observed. The corresponding RHF results yielded significantly lower agreement with available experimental data. Copyright © 1999 John Wiley & Sons, Ltd.