from first principles PP-I-1

PP-I-8Allylbenzene Double-Bond Migration in Gold-Containing CatalyticSystems: DFT StudyMukhamedzyanova D.F., Pichugina D.A., Kuz’menko N.E.Lomonosov Moscow State University, Chemistry department, Moscow, Russiamukhamedzyanova@phys.chem.msu.ruSupported metal particles on different bulk materials are effective catalytic systems, where thecombination metal-support is crucial. In present time nanosized gold particles deposited onvaried supports reveal high catalytic activity in numerous reactions, among which isallylbenzene double-migration. It has been shown that the activity of catalytic system inallylbenzene isomerization significantly depends on additional metal inclusion and support. Inorder to clarify the phenomena observed we have performed quantum-chemical simulation.The purpose of our work is to study the influence of morphology and charge, as well as Ausubstitution on Ni, on catalytic ability of gold particles in allylbenzene double-bondqmigration. In cluster approach the models of active sites are Au n (n=1, 4, 20, 21; q= -1,0,+1)and Au 3 Ni. The calculations have been carried out using DFT/PBE in scalar relativisticapproach with all-electron basis sets as implemented in Priroda 08 program. In order to studysupport influence regular C-support (the model is graphite(001)) and basic MgO(100) areconsidered. The calculations are performed within DFT/PBE framework with plane-wavebasis set and ultrasoft pseudopotentials in periodic boundary conditions using CASTEP 5.5.The supercomputers SKIF MSU «Chebyshev» and «Lomonosov» are used.The activation of allylbenzene double-bond through π-complex formation is observed at lowcoordinatedgold atoms (corner and edge atoms of a cluster). Three possible mechanisms ofallylbenzene double-bond migration have been found out. The most optimal path ofallylbenzene isomerization is at charged atoms of gold clusters via metal-allylic mechanism,where gold-hydride complex is an intermediate.It is possible to control active sites formation by two modes: (i) additional metal inclusion,and (ii) support variation. We have studied the influence of additional metal (Ni) on themechanism and an activation energy of the rate-determining step in allylbenzeneisomerization. The modification of gold particle morphology and charge, as well as goldmigration processes are studied on the surfaces of MgO(100) and graphite(001).This work was financially supported by the Council on Grants at the President of the RussianFederation (Grant 107.2011.3).124