Quantum-chemical study of the complexation of maleimide with benzene and water molecules

The density functional theory methods (B3LYP and PBE0) and the Möller-Plesset perturbation theory methods of second, third, and fourth orders (MP2, MP3, and MP4) are used to calculate the structure and energy of molecular complexes of benzene with maleimide and water, maleimide dimers in the ground and lowest excited triplet state, and the energies of interaction of the molecules in the complexes. The perturbation theory methods predict the existence of bound states for all the complexes studied. The largest binding energies are obtained for the benzene-maleimide complex, a result that explains why maleimide-based dispersants are used to disintegrate molecular associates of hydrocarbons in petroleum fractions.