A DFT study on the Pd-mediated decarboxylation process of aryl carboxylic acids

Decarboxylation process in a series of PdL2X(eta(2)-OOCArR) complexes 2OS(R) (L = DMSO; X = OOCCF3-; R = H, OMe, NO2, Me and CN) with substituent R at an ortho, meta or para position were investigated with the aid of density functional theory calculations. Through our study, we found that the OOCCF3 ligand is not just a spectator ligand but assists the decarboxylation process. The results indicated that electron-donating substituents have greater promotion effect than electron-withdrawing substituents on the decarboxylation process. An ortho substituent in the substrate ligands OOCArR- is normally necessary for a successful decarboxylation. The reason behind this has been explained.