Bond shift isomerization in cyclic and acyclic (triene)Fe(CO)(3) complexes. A density functional study

The 1,3-metal shift process has been studied for several conjugated cyclic and acyclic (eta (4)-triene)Fe(CO)(3) systems. In all cases the transition state of the process corresponds to (eta (2)-triene)Fe(CO)(3) structures. T he computed energy barriers are notably higher for acyclic complexes than f or the cyclic ones, in good agreement with the experimental observations. T he analysis of the energy barriers shows that this is due to the different orientations of the triene ligand in the transition states, which leads to more efficient stabilizing metal-ligand orbital interactions for the cyclic systems.