Structure and conformational equilibrium in substituted [(eta(4)-butadiene)Fe(CO)(3)] complexes: A density functional study

The energy profiles corresponding to C-C rotation in several carbonyl- and olefin-substituted derivatives of [(eta(4)-butadiene)Fe(CO)(3)] have been s tudied through density functional calculations, The energy differences betw een s-cis and s-trans conformations show an excellent correlation with the diastereoselectivities experimentally observed in several reactions. These energy differences have been rationalized through an analysis of the iron- butadiene bond, and the role played by the metal in the conformational pref erences is discussed.