Theoretical and experimental NMR Study of a series of five Nitrobenzene-1,2-Diamines

1H-, 13C-, and 15N-NMR studies of five nitrobenzene-1,2-diamines in solution and solid state have been achieved and the experimental chemical shifts and coupling constants agree with the theoretical values obtained at the B3LYP/6-311 + +G(dp) computational level using the geometries fully optimized with the hybrid HF/DFT B3LYP method and the 6-31G(d) basis set. The GIAO approximation has been used to calculate the absolute shieldings. The contribution of the substituents to the 15N chemical shifts of the amino groups could be quantified using a presence/absence matrix and a multiple regression. © 2013 Copyright Taylor and Francis Group, LLC.Peer Reviewe

13C and 15N NMR spectra of aminobenzimidazoles in solution and in the solid state

The 13C [hexadeutero-dimethylsulfoxide (DMSO-d6), hexamethyl-phosphoramide (HMPA)-d18 and solid-state] and 15N (solid-state) NMR spectra of six C-aminobenzimidazoles have been recorded. The tautomerism of 4(7)-aminobenzimidazoles and 5(6)- aminobenzimidazoles has been determined and compared with B3LYP/6-311++G(d,p) calculations confirming the clear predominance of the 4-amino tautomer and the slight preference for the 6-amino tautomer. GIAO-calculated absolute shieldings compare well with experimental chemical shifts. Copyright © 2008 John Wiley & Sons, Ltd.Peer Reviewe