| Benzimidazoles have far reaching applications in the field of chemistry and beyond. The major focus of this work is on the synthesis of benzimidazoles and bis(benzimidazoles) and subsequent complexation chemistry which has been further applied to areas such as constrained geometry and catalysis. A number of new techniques, such as the facile oxidation of methylene bridged benzimidazoles, have been elucidated in this study. Many improvements in experimental conditions have also been found in the syntheses of members of this class of compounds. We report here the preparation and characterization of two systems with constrained coordination geometries. The first consists of tetrahedrally constrained complexes using bis[rac-2,2-bis[2-(1-alkylbenzimidazol-2-yl)]biphenyl] characterized with several transition metal ions. The second consists of chiral, square-bipyramidally constrained complexes using chiral bis[1,2-bis(1-alkylbenzimidazol-2-yl)-1',2'-bis(alkoxy)ethane] with first and second row transition metal ions. The copper complexes of selected bis(benzimidazoles) have been found to catalyze the oxidative carbonylation of methanol to form dimethyl carbonate. Such complexes have also been found to be remarkable polymerization catalysts with the ability to homopolymerize and copolymerize olefins and acrylates. |
