Ag-N-heterocyclic carbene complexes and their catalytic properties

N-heterocyclic carbenes (NHCs) have emerged as powerful and versatile ligands in modern coordination chemistry. Due to their electron-rich structures, they provide strong σ-donor interactions to the metal center, thereby enhancing both the stability and catalytic efficiency of the complexes. Silver–NHC complexes combine the strong σ-donor properties of NHC ligands with the soft Lewis acidic character of silver, resulting in a unique chemical profile. These complexes are particularly noteworthy as stable precursor catalysts. In recent years, Ag–NHC complexes have also been employed in A3 coupling reactions, which involve the three-component condensation of aldehydes, amines, and alkynes. A3 couplings represent a powerful method for the synthesis of propargylamines, which serve as versatile intermediates in the preparation of various nitrogen-containing compounds. Since the application of Ag–NHC complexes in this area has remained limited, and the reaction scope has so far been investigated with only a narrow range of substrates, this thesis aims to develop new catalysts and broaden substrate diversity. Accordingly: • Benzimidazolium salts bearing 2,2-diethoxyethyl and 2,2-dimethoxyethyl substituents on nitrogen were synthesized and structurally characterized using appropriate spectroscopic techniques. • The synthesized benzimidazolium salts were converted into Ag–NHC complexes, which were likewise characterized spectroscopically. • The catalytic activities of the resulting Ag–benzimidazol-2-ylidene complexes were evaluated in A3 coupling reactions.