Olefin insertion in the Ru–H and Ru–F bonds of pentacoordinated d6 Ru(II) species: a DFT study

DFT (B3PW91) calculations have been carried out to study the impact of a spectator ligand X on the insertion of ethylene into the Ru-H bond of RuL2HX+q(X = Cl, q= 0, X = CO, q= 1, L = PH3). It is shown that the energy barrier is higher for X = CO than Cl, which is related to the energy to distort RuL2HX+q on going from the ground state to transition state. The insertion of fluoroethylene into the Ru-H bond of RuL2HCl shows that the fluorine substituent on the olefine does not influence much the energy of the reaction, and that insertion yields preferably an -F substituted ethyl complex. Insertion of ethylene into the Ru-F bond of RuL2FCl has also been studied. It is found to have a higher activation barrier compared to the insertion of ethylene in the Ru-H bond.