New insight into the mechanism of Pt(0)-catalyzed hydrosilylation reaction of (CH3)3SiH with CH2CHSi(CH3)3

The non-catalytic hydrosilylation reaction has much high activation energy due to large differences in the energy of HOMO-LUMO pairing and restriction of the orbital symmetry overlap. For Pt(0)-catalytic hydrosilylation, the electronic structure of Me3SiH has been modified by the oxidative addition of Pt(0). It not only narrows down the energy differences between the bonding orbitals but also improves the orbital overlap symmetry, leading to the effective decrease of the activation energy. The trouble for the Pt(0)-catalytic hydrosilylation is the formation of the majority of the Pt-containing intermediates. Because they are fallen into the deep potential-energy, the reductive eliminations are energetically prohibitive, which is the essence of Pt-contamination. The reductive elimination can be achieved with the ligand exchange method, and the energy barrier can be tuned by suitable ligands.