title: Assessment of the tautomeric population of benzimidazole derivatives in solution: a simple and versatile theoretical-experimental approach.
abstract: Herein, we present a simple and versatile theoretical-experimental approach to assess the tautomeric distribution on 5(6)-aminobenzimidazole (5(6)-ABZ) derivatives in solution via one-photon absorption. The method is based on the optimized weighted sum of the theoretical spectra of the corresponding tautomers. In this article we show how the choice of exchange-correlation functional (XCF) employed in the calculations becomes crucial for the success of the approach. After the systematic analysis of XCFs with different amounts of exact-exchange we found a better performance for B3LYP and PBE0. The direct test of the proposed method on omeprazole, a well-known 5(6)-benzimidazole based pharmacotherapeutic, demonstrate its broader applicability. The proposed approach is expected to find direct applications on the tautomeric analysis of other molecular systems exhibiting similar tautomeric equilibria.
authors.affiliation: Department of Chemistry, University of Central Florida, P. O. Box 162366, Orlando, FL, 32816-2366, USA.
authors.forename: Carlos
authors.initials: C
authors.lastname: Diaz
authors.forename: Ligia
authors.initials: L
authors.lastname: Llovera
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Echevarria
authors.forename: Florencio E
authors.initials: FE
authors.lastname: Hernández
mesh_terms: D001562:Benzimidazoles / Q000737:chemistry*; D007536:Isomerism; D009682:Magnetic Resonance Spectroscopy; D017785:Photons; D012996:Solutions / Q000737:chemistry*
chemical_list: D001562:Benzimidazoles; D012996:Solutions; C031000:benzimidazole