Crystallographic and Computational Analysis of the Supramolecular Structure of 2,5-Dimethylpyrazolo[1,5-a]pyrimidin-7(4H)-one

Abstract  

The structure of 5-dimethylpyrazolo[1,5-a]pyrimidin-7(4H)-one 1 has been determined by X-ray crystallography. The compound 1 crystallizes in the space group P−1 with two molecules in the asymmetric unit solvated with one molecule of the acetic acid The unit cell parameters are a = 8.796(1) ?, b = 10.531(1) ?, c = 10.680(1) ?, α = 96.901(2)o, β = 98.135(2)o, γ = 107.248(2)o. In the crystal molecules A and B are linked into R ₂²(9) hydrogen bonded rings and these rings form chains parallel to [101] Overall, the supramolecular structure 1 consists of two hydrogen bonded and two π–π stacking dimers. An energetic interplay between these dimers has been studied using B3LYP DFT calculations. In addition π–π interactions are analyzed using the Bader’s atoms in molecules’ (AIM) theory.