Does the Intramolecular Hydrogen Bond Affect the Spectroscopic Properties of Bicyclic Diazole Heterocycles?

Figure 2

Correlation between electron density at the H-bond critical points ρ_BCP (in a.u.) and the H^…O distance (in Å) was calculated at the B3LYP/aug-cc-pVDZ level. (4, 7, 10, 13, 16, 19, and 22; R₂ = CHCl₂) (5, 8, 11, 14, 17, and 20; R₂ = CH₃).