The displacement of η2-coordinated ligands from the photolytically generated CpMn(CO)2L and BzCr(CO)2L [Cp = η5-C5H5, Bz = η6-C 6H6, L = 2,3-dihydrofuran (DHF), furan] complexes by pyridine has been studied. The displacement reactions span a wide range of time scales from microseconds to hours and were studied using a range of time-resolved IR spectroscopic techniques. The substitution reactions follow a dissociative pathway and the measured activation enthalpies provide an estimate for the strength of the metal - (η2-furan) and metal - (η2-DHF) interactions. In these complexes, the Cr center binds both ligands weaker than the Mn center. There is a ∼6-10 kcal/mol difference in the binding enthalpies of η2-furan and η2-DHF to both metals suggesting that this difference is the result of a partial loss of resonance energy in the case of the aromatic furan ligand upon interaction with the metal.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Inorganic Chemistry