| The N-heterocyclic carbene (NHC) ligands have been used widely in catalysis and in coordination chemistry. They have proved to be efficient ancillary ligands because of their strong coordination ability, and their tunable character, through the introduction of appropriate substituents at the nitrogen atoms or at the five-membered-ring carbon atoms, which allows for the control of the sterical and electronic properties on the metal center. Besides, N-heterocyclic carbene ligands are nontoxic and cheap. Therefore, NHCs are excellent alternative of phosphines ligands and have drawn great attention for the design of organometallic catalysts. In this thesis, we describe the synthesis, catalytic performance and immobilization of N-donor containing NHC metal complexes as follows:In section one:Pd, Ir and Ru complexes bearing acylic imino-NHC ligands, in which the imine carbon bonds directly to the carbene nitrogen, were synthesized and characterized. The catalytic performance of Pd complexes for Suzuki-Miyaura cross-coupling reactions in pure water and Ir and Ru complexes for transfer hydrogenation of ketones and imines were tested in a wide scope of substrates. Besides, it is found that different counteranions in Ru complexes obviously affect the yields of the transfer hydrogenation of less activated4-iodoacetophenone. These results demonstrate the high versatility and application potential of acylic imino-N-heterocyclic carbene ligands in the design of effective homogeneous catalysts.In section two:Four SBA-15immobilized N-donor containing NHC palladium catalysts were synthesized and fully characterized. They were employed as heterogeneous catalysts in the Suzuki-Miyaura cross-coupling reactions of aryl chlorides and arylboronic acids. The effect of the property of N-donors was investigated. Catalyst9, in which the amino group links steady to the NHC moiety, with the largest steric hinder displays the best performance. |
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