Two amidine derivatives studied by 1H, 13C, 14N, 15N NMR and GIAO-CHF calculations
Abstract
1 H, 13C, 14N, and 15N NMR data are presented for two amidine derivatives and their complexes with TFA in 1:1 and 1∶2 molar ratios. The protonation site at the N5 atom was established based upon the observed coupling constants, NOE interactions, and chemical shift change. The GIAO-CHF calculations were also performed for the free bases and their N5 cations.