Annulated derivatives of 2,2'-biimidazole, 2-(2'-imidazolyl)benzimidazole, and 2,2'-bibenzimidazole

Preparation of bisannulated salts of 2,2'-biimidazole, 2-(2'-imidazolyl)benzimidazole, 2,2'-bibenzimidazole, and annulated salts of 1,1'-dimethyl-2,2'-biimidazole, 1,1'-dimethyl-2-(2'-imidazolyl)benzimidazole, and 1,1'-dimethyl-2,2'-bibenzimidazole is accomplished by direct alkylation of the parent azaheterocycle with excess 1,n-dihaloalkane. Discussions of the product conformations use electronic absorption spectra and NMR. The redox potentials of these salts are measured in DMF and CH3CN, and become increasingly more negative and less reversible as the systems become less planar.