Time-Resolved Infrared Spectroscopy Studies of Olefin Binding in Photogenerated CpRu(CO)X (X = Cl, I) Transients
作者:Sohail Muhammad、Samuel J. Kyran、Rajesh K. Raju、Edward N. Brothers、Donald J. Darensbourg、Ashfaq A. Bengali
DOI:10.1021/om300197b
日期:2012.5.28
The mechanism and energetics of ligand (L) substitution (L = THF, cyclopentene, cyclohexene, cyclooctene) from photogenerated CpRu-(CO)(X)L (X = Cl, I) complexes were studied using time-resolved infrared spectroscopy. The reactions proceed through a dissociative mechanism, and the Ru-L binding enthalpies were estimated. The trend in the bond enthalpies, Ru-(eta(2)-cyclooctene) approximate to Ru-(eta(2)-cyclopentene) > Ru (eta(2)-cyclohexene), is correlated with the strain energy of the cycloalkene ring. For all ligands investigated, CpRu(CO)(Cl)-L binding enthalpies were lower than those for the analogous CpMn(CO)(2)-L and BzCr(CO)(2)-L complexes. DFT calculations indicate that the lower binding enthalpy for the Ru-L complexes is due to a greater reorganizational energy for the CpRu(CO)Cl fragment as it adopts a configuration suitable for interaction with the ligand.