Synthesis, Characterization And Properties Of Imidazole Derivatives

Imidazole derivatives which possess good physiological activities, unique optical and magnetical properties have broad applications as drugs, pesticides, functional materials, surfactants, reagents in chemical analysis and organic synthesis. In this thesis, we mainly studied two areas: the synthesis and application of imidazolium ionic liquids; the synthesis of imidazole derivatives ligands and complexes. Based on the detailed investigation of related literature, our work was carried out as followed:(1) Esterification of boric acid, pinacol, and cycloexanol has been studied in ionic liquids, including 1-methylimidazolium hydrogen sulfate [Hmim]HSO₄, 1-butyl-3-methylimidazolium hydrogen sulfate [C4mim]HSO₄, 1-butyl-3-methylimidazolium hexafluorophosphate ([Bmim]PF6), 1-butyl-3-methylimidazolium tetrafluoroborate ([Bmim]BF₄), 1-methyl-3-(3-sulfopropyl)- imidazolium hydrogen sulfate [(CH2)3SO3Hmim]HSO₄, 1-methylimidazolium tetrafluoroborate [Hmim]BF4. The influences of the types of ionic liquids, reaction temperature, reaction time and mole ratio of reactants to IL on yields of boric acid esters have been investigated. The results showed that under the optimized conditions [n (boric acid)﹕ n (pinacol)﹕ n (cyclohexanol)﹕ n ([Hmim]HSO₄)=1﹕1﹕1﹕1, 80℃and 2 h], the yield of 2-cyclohexyloxy- 4,4,5,5–tetramethyl -[1,3,2] dioxaborolan could reach up to 95.6%. The ionic liquid can be used repeatedly for four times without remarkable loss of catalytic activity.(2) Esterification of boric acid, aliphatic alcohols with different length (methanol, ethanol, propanol, butanol, 1-pentanol) has been studied in [Hmim]HSO₄. The length of alkyl chains alcohols could affect the conversion rate greatly, the ionic liquid [Hmim]HSO₄ was entirely miscible with trimethyl borate and triethyl borate, the system was homogenous. With increasing the length of alkyl chains, the reaction systems were biphasic gradually at the end of reaction. It could be seen that the catalytic activity was slightly increased with the increasing the length of alkyl chains.(3) Three novel N,N'-sbustituted 2,2′-biimidazole derivatives, 2,2'-(2,2'-biimidazole-1,1'-diyl) diethanoic acid, 2,2'-(2,2'-biimidazole-1,1'-diyl) dibutyric acid, 2,2'-(2,2'-biimidazole-1,1'-diyl) dipentanoic acid have been prepared based on 2,2′-biimidazole, and the products were characterized by IR.(4) 2,2'-(2,2'-Biimidazole-1,1'-diyl)diethanoic acid was employed to synthesize binuclear metal complexes [Co2L2(H2O)4]·6H2O, [Ni2L2(H2O)4]·6H2O and polymeric complexes {[Mn₄L₄(H₂O)₄]·6H₂O}n, which were characterized by X-ray single-crystal diffraction, IR and elemental analysis. The magnetic property of Mn complex was investigated by solid state magnetic susceptibility (χm) measurements.