An evaluation of the GLYCAM06 and MM3 force fields, and the PM3-D* molecular orbital method for modelling prototype...

The structures and interaction energies of 21 binary complexes of fucose and glucose with toluene, 3-methylindole or p-hydroxytoluene, evaluated at the DFT-D level, are used to judge the accuracy of the GLYCAM06 and MM3 force fields, and the PM3-D* molecular orbital method for modelling carbohydrate-arene interactions. The accuracy of the DFT-D method is substantiated by comparison with high level CCSD(T) calculations on a small number of representative complexes. It is found that a correct description of the intermolecular dispersive interactions is essential. Both the PM3-D* method and the GYLCAM06 force field yield interaction energies within 1 kcal mol⁻¹ of the DFT-D values, whilst those from the MM3 force field are in error by more than 2 kcal mol⁻¹.