DFT study of group 8 catalysts for the hydrophenylation of ethylene: Influence of ancillary ligands and metal identity

Abstract

Computational methods are used to investigate catalytic hydrophenylation of ethylene using complexes of the type [(Y)M(L)(CH 3)(NCMe)] n + [Y = Mp, n = 1; Y = Tp, n = 0; M = Ru or Os; L = PMe 3, PF 3, or CO; Mp = tris(pyrazolyl)methane; Tp = hydrido- tris(pyrazolyl)borate]. The conversion of ethylene and benzene to ethylbenzene with [(Y)M(L)(Ph)] n + as catalyst involves four steps: (1) ethylene coordination, (2) ethylene insertion into the M–Ph bond, (3) benzene coordination, and (4) benzene C–H activation. DFT calculations form the basis to compare stoichiometric benzene C–H activation by [(Y)M(L)(CH 3)(NCMe)] n + complexes to yield methane and [(Y)M(L)(Ph)(NCMe)] n +. In addition, starting from the 16-electron species [(Y)M(L)(Ph)] n +, potential energy surfaces for the formation of ethylbenzene are calculated to reveal the impact of modifications to the scorpionate ligand (Mp or Tp), co-ligand (L) and metal center (M).