H2 Activation by Heterobimetallic Gold(I)/Platinum(0) Complex: Theoretical Understanding of Electronic Processes and Prediction on More Active Species
journal contributionposted on 14.02.2020, 15:04 by Lei Zhang, Shiyu Hu, Linlin Yang, Wei Li, Shuhua Li, Wei Wang, Guixiang Zeng
Mechanistic studies on H2 activation by the Au(I)/Pt(0) bimetallic complex as well as the electronic processes were investigated with the density functional theory method. In the reaction, the H–H bond is heterolytically cleaved through the cooperative functions of the Lewis acid Au(I) center and the Lewis base Pt(0) center, where the Gibbs energy barrier (ΔG°‡) and Gibbs reaction energy (ΔG°) are 22.6 and 8.9 kcal/mol, respectively. In the transition state, the charge transfer (CT1, 0.364 e) occurs from the σ bonding orbital of H2 to the antibonding d orbitals of the Au–Pt moiety. The reverse CT2 (0.205 e) mainly occurs from the occupied d orbitals (dxz and dz2) of the Pt(0) moiety to the σ* antibonding orbital of H2. By substituting the noble metal Pt in the Au(I)/Pt(0) complex for the cheaper metal Ni, the activity of the bimetallic complex is largely improved, where the ΔG°‡ and ΔG° values considerably decrease to 16.7 and −13.7 kcal/mol, respectively. The improvement of activity comes from the facile CTs in the H2 activation by the Au(I)/Ni(0) system.