Figure 8
From: Tautomerism of4,4′-dihydroxy-1,1′-naphthaldazine studied byexperimental and theoretical methods
Optimized structures (B3LYP/6-31 G**) of the possible tautomersof compound 1 , diol (a), keto (b) with some of their isomers, andthe diketo tautomer (c). The dihedral angles 1) and 3) aredefined between the N- and quaternary C-atom, as shown in a-R1, angle 2)is the C-N-N-C, and their values are given. The lower, light-blue partof each molecule is oriented in the same way in all structures forbetter visualisation of the conformational differences between thecalculated isomers.