A computational investigation of the interactions between harmane and the functional monomers commonly used in molecular imprinting

In this study, the density functional (DFT) method with the hybrid B3LYP exchange-correlation functional has been applied to investigate the intermolecular interactions between harmane and the selected functional monomers: methacrylic acid (MAA) and 2-hydroxyethyl methacrylate (HEMA), most commonly used in the preparation of molecularly imprinted polymers (MIPs). For this purpose possible conformations of 1:n (n <= 4) harmane/functional monomer systems have been optimized with the use of the DFT(B3LYP)/6-31G(d,p) method. The most stable configurations of harmane/functional monomer 1:n (n <= 4) complexes have been selected. The positions and the geometrical parameters of hydrogen bonding sites in the optimized 1:n harmane/functional monomer systems have been determined. The binding energies Delta E-bind of the optimized systems have been calculated taking into account the basis set superposition error (BSSE) and the zero-point vibrational energies (Delta ZPVE) corrections. Based on the conformational analysis and the Calculated binding energies of harmane/monomer molecular systems, we have concluded that the interactions between harmane and MAA are more specific and stronger in comparison to the interactions between harmane and HEMA. (C) 2009 Elsevier B.V. All Fights reserved.