Intramolecular Hydrogen Bond, Hirshfeld Analysis, AIM; DFT Studies of Pyran-2,4-dione Derivatives

Intra and intermolecular interactions found in the developed crystals of the synthesized py-ron-2,4-dione derivatives play crucial rules in the molecular conformations and crystal stabili-ties, respectively. In this regard, Hirshfeld calculations were used to quantitatively analyze the different intermolecular interactions in the crystal structures of some functionalized py-ran-2,4-dione derivatives. The X-ray structure of pyran-2,4-dione derivative namely (3E,3 ' E)-3,3 '-((ethane-1,2-diylbis(azanediyl))bis(phenylmethanylylidene))bis(6-phenyl-2H-pyran-2,4(3H)-dione) was determined. It crystallized in the monoclinic crystal system and C2/c space group with unit cell parameters: a = 14.0869(4) angstrom, b = 20.9041(5) angstrom, c = 10.1444(2) angstrom and beta = 99.687(2)degrees. Generally, the H horizontal ellipsis H, H horizontal ellipsis C, O horizontal ellipsis H and C horizontal ellipsis C contacts are the most important interactions in the molecular packing of the studied pyran-2,4-diones. The molecular structure of these compounds is stabilized by intramolecular O horizontal ellipsis H hydrogen bond. The nature and strength of the O horizontal ellipsis H hy-drogen bonds were analyzed using atoms in molecules calculations. In all compounds, the O horizontal ellipsis H hydrogen bond belongs to closed-shell interactions where the interaction energies are higher at the optimized geometry than the X-ray one due to the shortening in the A horizontal ellipsis H distance as a con-sequence of the geometry optimization. These compounds have polar characters with different charged regions which explored using molecular electrostatic potential map. Their natural charges, reactivity descriptors and NMR chemical shifts were computed, discussed and compared.

Automated summary

In the synthesized pyran-2,4-dione derivatives, intra and intermolecular interactions play crucial roles in molecular conformations and crystal stabilites, with Hirshfeld calculations used to quantitatively analyze different intermolecular interactions. The X-ray structure of a specific pyran-2,4-dione derivative was determined, revealing important O⋯H hydrogen bonds and closed-shell interactions. The compounds exhibit polar characteristics with different charged regions, as explored through molecular electrostatic potential maps.