Assessment of density functional methods for the study of olefin metathesis catalysed by ruthenium alkylidene complexes

Performance of 31 DFT methods in thermochemistry of olefin metathesis involving the model catalyst (PH3)(2)(Cl)(2)Ru=CH2 is studied using the CCSD(T) reference energies. The best methods are M06, omega B97X-D and PBE0, followed by MPW1B95, LC-omega PBE, M05-2X and B1B95. Among 20 functionals tested in reproduction of experimental PCy3 dissociation energy for the Grubbs catalyst (H(2)IMes)(PCy3)(Cl)(2)Ru=CHPh, the M06-class and M05-2X methods are most accurate. omega B97X-D overestimates the dissociation energy, whereas MPW1B95, LC-omega PBE, PBE0 and B1B95 underestimate it, similarly to other methods, which give larger errors. LC-omega PBE, B1B95, MPW1B95 and PBE0 provide the best geometries. (C) 2010 Elsevier B. V. All rights reserved.