Ru(Me -Allyl)2(COD) ∆EI→II ∆EIV →V significantly smaller when compared to Reaction 1 in Fig. . Such findings already point to subtle differences in the electronic properties of the molecules which induce a different binding behavior. Despite these minor differences, it clearly can be seen that the highest yields can be observed for vanishing energy differences ∆∆E ≈ 0 in good agreement with our previous findings. Moreover, the most suitable catalysts are (PPh 3 ) 3 RuCl 2 , Ru(Me-Allyl) 2 (COD)