Please use this identifier to cite or link to this item: http://scholarbank.nus.edu.sg/handle/10635/20601
Title: Non-classical carbene ligands and their coordination chemistry
Authors: ONG HONG LEE
Keywords: carbene, NHC, n-heterocyclic carbene, catalysis, synthesis, non-classical
Issue Date: 12-Aug-2010
Source: ONG HONG LEE (2010-08-12). Non-classical carbene ligands and their coordination chemistry. ScholarBank@NUS Repository.
Abstract: This thesis deals with the synthesis, characterization and catalytic studies of palladium organometallic compounds bearing ligands which are potentially remote N-heterocyclic carbenes (rNHCs). Two systems were investigated: the R2-2Ph-bim and the R2-Me-bim systems. In the first system, the 2-(4-bromophenyl)benzimidazole core was doubly N-alkylated to form the proligands (Et2-2Ph-bim-Br)+BF4- (6), (EtBn-2Ph-bim-Br)+BF4- (7), (Bn2-2Ph-bim-Br)+BF4- (8) Oxidative addition of these proligands to Pd(PPh3)4 yielded the complexes [PdBr(Et2-2Ph-bim)(PPh3)2]+BF4- (9), [PdBr(EtBn-2Ph-bim)(PPh3)2]+BF4- (10), [PdBr(Bn2-2Ph-bim)(PPh3)2]+BF4- (11). Analysis on the nature of the ligands in question as carbenes revealed that complexes 9-11 may not be rNHC complexes. In the second system, the 6-Bromo-2-methylbenzimidazole core was doubly N-alkylated to synthesize the proligand (Bn2-2Me-bim-Br)+BF4- (14). Its corresponding palladium complex, [PdBr(Bn2-2Me-bim)(PPh3)2]+BF4- (15) was synthesized via oxidative addition of the proligand to Pd(PPh3)4. We expect 15 to display carbene characteristics based on a study on its spectroscopic data. 15 performed moderately well for the catalysis of standard Sonogashira coupling reactions.
URI: http://scholarbank.nus.edu.sg/handle/10635/20601
Appears in Collections:Master's Theses (Open)

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