title: Aggregation of 2-aminobenzimidazole--a combined experimental and theoretical investigation.
abstract: An investigation of 2-aminobenzimidazole was carried out by calculations at HF, MP2, and DFT levels of theory and also by UV and IR spectroscopy. The quantum chemical calculations predict a full shift of the equilibrium towards the amino form, but the absorption spectra in different solvents distinctly show a two-component equilibrium system. Examination of possible equilibria in solution shows that an equilibrium between two dimeric forms of the amino tautomer of 2-aminobenzimidazole explains the spectral observations.
authors.affiliation: Institute of Organic Chemistry with Centre of Phytochemistry, Bulgarian Academy of Sciences, Sofia, Bulgaria. sea@orgchm.bas.bg
authors.forename: Silvia E
authors.initials: SE
authors.lastname: Angelova
authors.forename: Milena I
authors.initials: MI
authors.lastname: Spassova
authors.forename: Vera V
authors.initials: VV
authors.lastname: Deneva
authors.forename: Marin I
authors.initials: MI
authors.lastname: Rogojerov
authors.forename: Liudmil M
authors.initials: LM
authors.lastname: Antonov
mesh_terms: D001562:Benzimidazoles / Q000737:chemistry*; D019281:Dimerization; D015394:Molecular Structure; D011789:Quantum Theory; D012997:Solvents; D013057:Spectrum Analysis; D013816:Thermodynamics
chemical_list: D001562:Benzimidazoles; D012997:Solvents; C027391:2-aminobenzimidazole