F. Pasha, A. Bendjeriou-Sedjerari, K.-W. Huang, J.-M. Basset
Organometallics, 33 (13), 3320-3327, (2014)
Density functional theory (DFT) was used to elucidate the mechanism of n-butane hydrogenolysis (into propane, ethane, and methane) on well-defined zirconium hydrides supported on SBA15 coordinated to the surface via N-donor surface pincer ligands: [(≡SiNH−)(≡SiO−)ZrH2] (A), [(≡SiNH−)2ZrH2] (B), [(≡SiNH−)(≡SiO−)2ZrH] (C), [(≡SiNH−)2(≡SiO−)ZrH] (D), [(≡SiN═)(≡Si–O−)ZrH] (E), and [(≡SiN═)(≡SiNH−)ZrH] (F). The roles of these hydrides have been investigated in C–H/C–C bond activation and cleavage. The dihydride A linked via a chelating [N,O] surface ligand was found to be more active than B, linked to the chelating [N,N] surface ligand. Moreover, the dihydride zirconium complexes are also more active than their corresponding monohydrides C–F. The C–C cleavage step occurs preferentially via β-alkyl transfer, which is the rate-limiting step in the alkane hydrogenolysis. The energetics of the comparative pathways over the potential energy surface diagram (PES) reveals the hydrogenolysis of n-butane into propane and ethane.