Role of ionic liquids on the reactivity and selectivity of diels- alder reactions and single site catalysts

Abstract

Ionic liquids (ILs) have gained interest because of their features such as high thermal stability, high chemical inertness, conductivity, their ability to dissolve organic and inorganic substances. It is possible to tune these properties offering advantages for a wide range of applications namely solutions, synthesis and catalysis. In this thesis, the solvent and ligand effects of ILs are investigated in the case of organic reactions and single-site catalysts (SACs) by using Density Functional Theory (DFT). Then, the influence of electron-donor/acceptor properties of the SACs on the catalytic activities and stabilities of Ir/Rh including complexes are examined by means of computational tools. Firstly, the role of ILs as solvents in the Diels-Alder reactions is modeled. The fact that ILs can have hydrogen bonding interac tions with the dienophiles, and thus significantly affect the endo selectivity and the rate of the Diels-Alder reactions has been assessed. The atomically dispersed catalysts in the pres ence of SiO2-, γ-Al2O3- and MgO supported-Ir(CO)2 complexes are analyzed in order to understand the support effects on the electronic properties of the active sites and stabilities of the catalysts. Chapter 5 deals with the electron-donor/acceptor properties of ILs by us ing IL coated/uncoated MgO supported Ir(CO)2 complexes in the presence of [Bmim][OAc] and [Bmim][PF6]. In order to understand the ligand effects on the catalytic properties of the SACs, ligand modification reactions between carbonyl and acetylene groups in the case of zeolite- supported Rh(CO)2 complexes are modeled by considering the proton mobility. Finally, the hydrogenation reaction mechanisms for 1,3-butadiene over γ-Al4O6 supported Ir(CO)2 complex is studied and the reasons behind the 1-butene selectivity have been clari fied. Overall, this study contributes to a better understanding of the solvent and ligand effects of ILs on the chemical reactions and the catalytic systems.