Synthesis, Crystal Structure and Properties of Iodide and Hexafluorophosphate Salts of 2-Ferrocenyl (or Binuclear Ferrocenyl)-1,3-dialkylbenzimidazolium

Iodide salt 4 and hexafluorophosphate salt 5 of 1-methyl-2-ferrocenyl-3-ethylbenzimidazolium are prepared using 2-ferrocenylbenzimidazole 2 as starting material. 2-[1'-(2-Ferrocenylpropan-2-yl)ferrocen-1-yl]benzimidazole (7) is obtained by the reaction of formyl 2,2-diferrocenylpropane with o-diaminobenzene in the condition of methanol as solvent, reflux and catalysis of iodine. Iodide salt 9 and hexafluorophosphate salt 10 of 1-methyl-2-[1'-(2-ferrocenylpropan-2-yl)-ferrocen-1-ly]-3-ethylbenzimidazolium are synthesized using 7 as starting material. Oxidative potentials of ferrocenyl connected directly to benzimidazolium in these salts move to more positive position to a large extent. Crystal structure of 4 is explained and pi-pi stacking is showed. UV-Vis spectra shows that photoinduced charge transfer exists for salts. Iodide salt 4 presents good catalytic effect on decomposition of ammonium perchlorate (AP) in DSC-TG (differential scanning calorimetry- thermogravimetric) test.