Structural and Electronic Characterization of M(dppp)Cl2 Catalysts with M=Ni, Pd, and Pt: A DFT Study

Experimental results indicate that the metal of the catalyst strongly affects the kinetics of polymerization and the regioregularity of synthesized poly-3-alkylthiophenes in M(dppp)Cl2 [dppp: 1,3-bis(diphenylphosphino) propane] catalyzed polymerization of 2,5-dibromo-3-alkylthiophene monomers. To make possible analyzing such effects in more detail, we have computationally investigated electronic structure of mostly known dppp including catalysts, M(dppp)Cl2, with M=Ni, Pd and Pt. To this end, molecular structure, partial charge of atoms, HOMO-LUMO energy gaps (ΔEHOMO-LUMO), and the values of the ρb, λ1, λ2, λ3 and 2ρb were fully determined by DFT and AIM analysis. Results from molecular structure analysis showed that, by replacing Ni atom with Pd and Pt, M-Cl and M-P bond length increase considerably, while Cl-M-Cl angle decrease slightly. Furthermore, ΔEHOMO-LUMO and partial charge on metal were decreased by this order Ni