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

Abstract

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 α-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.