Synthesis of polydentate carbene precursors and properties

Following the synthesis of the first stable carbene, N-heterocyclic carbene procursors and metal complexes of these ligands are formed an effective area on organometalic chemistry and catalysis. Mono and bidentat derivatives of N-heterocyclic carbene precursors are widespread in the literature. These complexes are used many reactions such as C-C bond formation, olefine methatesis, hydroxylation, hydroformilation and C-H aktivation. However polydentate N-heterocyclic carbene procursors and transition metal complexes which synthesed from these precursors have high catalytic efficiency in many reactions such as small molecule activation, C-H activation, C-C coupling reactions, hydrosilation and alkylation. Furtheremore chelating effects and preventing of formation of undesirable by-products in the catalytic reaction also increased interest in those carbide polydentate. Therefore tetrakis and hexakis azolium salts which contains benzimidazole and imidazoline core are synthesized in this study. The results could be summarized in four sections: 1) In the first part we discuss the tetrakis(azolium) salts and hexakis(azolium) salts from the synthesis N-substituted imidazoline and benzimidazole with 1,2,4,5-tetrakis(bromethyl)benzene and hexakis(bromomethyl)benzene. Structural investigation have been carried out with proper spectroscopic techniques. 2) Prepared azolium salts have been tested for Suzuki reaction in the presence of Pd(OAc)2, and carbenes formed in situ in the reaction media., and the catalytic activities were investigated. 3) Prepared azolium salts have been tested for Heck reaction in the presence of Pd(OAc)2, and carbenes formed in situ in the reaction media., and the catalytic activities were investigated. 4) Prepared azolium salts have been tested for arylation of heteroaryls in the presence of Pd(OAc)2, and carbenes formed in situ in the reaction media., and the catalytic activities were investigated.