95Mo nuclear magnetic resonance parameters of molybdenum hexacarbonyl from density functional theory: appraisal of computational and geometrical parameters

Abstract

Solid-state ⁹⁵Mo nuclear magnetic resonance (NMR) properties of molybdenum hexacarbonyl have been computed using density functional theory (DFT) based methods. Both quadrupolar coupling and chemical shift parameters were evaluated and compared with parameters of high precision determined using single-crystal ⁹⁵Mo NMR experiments. Within a molecular approach, the effects of major computational parameters, i.e. basis set, exchange–correlation functional, treatment of relativity, have been evaluated. Except for the isotropic parameter of both chemical shift and chemical shielding, computed NMR parameters are more sensitive to geometrical variations than computational details. Relativistic effects do not play a crucial part in the calculations of such parameters for the 4d transition metal, in particular isotropic chemical shift. Periodic DFT calculations were tackled to measure the influence of neighbouring molecules on the crystal structure. These effects have to be taken into account to compute accurate solid-state ⁹⁵Mo NMR parameters even for such an inorganic molecular compound.