Solvent–solute and non-covalent interactions on bis(4-Piperidinonium ethyl ketal) oxalate compound: DFT calculations and in silico drug-target profiling

Abstract

In the present paper, we deliver the synthesis, experimental results, and theoretical examination of a newly developed organic supramolecular compound, entitled bis(4-Piperidinonium ethyl ketal) oxalate, with the subsequent chemical formula: (C7H14NO2)2(C2O4), denoted by 4PEKOX. The stoichiometric 2:1 ratio of 4-Piperidinone ethyl ketal with oxalic acid, and the slow evaporation that follows, produce this new material. X-ray diffraction was carried out to identify the 4PEKOX asymmetric unit and its two-dimensional lattice. The attachment between 4-Piperidinonium ethyl ketal cations and oxalate anions is provided by N(C)-H…O H-bonds forming supramolecular units of type R22(8),R12(5) and R21(6). The inter-molecular interactions that contribute to crystal packing have been assessed through the use of the HS; the percentage participation of each interaction was presented as two-dimensional fingerprints. The infrared (IR) and UV–Visible spectroscopy allowed us to identify the functional groups and study the optical properties of 4PEKOX. Experimental investigations have been combined with quantum chemical calculations to confirm and evaluate the properties of 4PEKOX from a theoretical perspective, allowing us to explain and examine in detail the electronic transfer, polarity, atomic charges and the role of non-covalent interactions in this new compound. Secondly, the expected therapeutic effect of 4PEKOX as an organic supramolecular compound was studied using the molecular docking technique. We examined the effect of 4PEKOX on the SARS-CoV-2 (7JTL) protein and measured their interaction energy with it, comparing it with the energies of oxalic acid and heterocyclic amine separately with the same protein to show the evolution imposed by synthesis through the combination of organic molecules to produce supramolecules more reactive than the starting reagents. In this study, Favipiravir was used as a reference due to its potent therapeutic activity against multiple coronaviruses.