Displacement of the THF solvent molecule from (eta(5)-C5H5)Mn(CO)(2)THF bysimple two electron donor ligands: evidence for a dissociative mechanism and determination of the Mn-THF bond strength

The reaction between CpMn(CO)(2)THF (Cp = eta(5)-C5H5, THF = tetrahydrofura n) and nitrogen containing ligands is studied in THF solution. In all cases the products of the reaction are the known CpMn(CO)(2)L complexes (L = pip eridine, 4-acetylpyridine). The reaction of the solvated complex with both ligands studied proceeds through a purely dissociative mechanism. In good a greement with previous thermochemical measurements, kinetic analysis yields an average value of 24.0 +/- 3.0 kcal mol(-1) for the CpMn(CO)(2)-THF bond dissociation energy. The results of the present study clarify the relation ship between metal-solvent bond strengths obtained by kinetic methods and t hose obtained by thermochemical measurements. (C) 1999 Elsevier Science S.A . All rights reserved.