Theoretical study of aryl succinic and maleic acid derivatives

All ligands are susceptible to nucleophilic attacks in the carbonyl carbon, whether such carbon be ester, amide or imide. In accordance with the theoretical calculations, the lowest electron density is located in these regions. Furthermore, the heteroatoms are susceptible to suffering elecrophilic attack, which leads to the conclusion that the ligand-enzyme recognition is by retro-electron donation. This is confirmed by the energies of the HOMO of the aromatic ring as well as the LUMO of the lateral chains.