Journal of Molecular Structure | 2021
Diverse structural assemblies of a series of ninhydrin derivatives: Quantitative analyses from experimental and theoretical studies
Abstract
Abstract Three ninhydrin derivatives (2–4) have been synthesized where the reaction of ninhydrin with Meldrum s acid yielded [3.3.3] propellanoid (2) and ethyl 2,2-bis (1,3-dioxo-2,3-dihydro-1H-inden-2-yl)acetate (3) while with malononitrile yielded a spiroindenopyran (4). The products being crystalline in nature and are characterized by single crystal X-ray diffraction in addition to other spectroscopic studies. X-ray crystallography reveals that solid-state structure of the title compounds exhibits C‒H···π, π‒π and lone-pair(l.p)···π interactions in building supramolecular assemblies. Indeed, compound (2) was stabilized through extended supramolecular C‒H···π/π‒π/π···H‒C network whereas compounds (3) and (4) are stabilized through lone-pair (l.p)···π and π‒π interaction respectively. The diverse intermolecular interactions via Hirshfeld surface analysis enables quantitative contributions to the crystal packing that exposes the similarities and differences in the interactions experienced by each compound. The distinctive energy frameworks have been calculated for individual molecules and the interaction energies suggest that the contacts are largely dispersive in nature. The binding energies associated with the non-covalent interactions observed in the crystal structures have been calculated using theoretical DFT calculations. Finally, the interplay between the interactions have been characterized by Bader s theory of “atoms-in-molecules” (AIM).