theoretical study of the co dissociation mechanism in [(ƞ 5 -c 5 h 5 ) fe (co) 2 (ƞ 1 -c 5 h 5 )]

In this study, using theoretical calculations of dftdensity functions, co substitution reactions incyclopentadiene and indenyl ligands in complexes [(ƞ5-c5h5) fe (co)2(ƞ1-c5h5)] (i) which leads to theformation of sandwich complex fe(η5-c5h5)2 wereinvestigated. the free energy barrier of co dissociationprocess for complex i was calculated. the first cosubstitution giving an η2-cp complex has a higher barrierthan the second co substitution giving an η5-cpcomplex. this behavior was attributed to the increaseddegree of aromaticity of cp in the transition stateconnecting the η2-cp complex to the η5-cp complex.calculations show that first and second co substitutionreactions different take place through the formation oftwo monochromonyl endo and exo isomeric. finally, itwas found that the pathway is more accessible to the cosubstitution reaction through the exo-isomerintermediate.