Electronic aspects of hydrogen bond patterns of P=O···H in crystal structures of phosphoramido acid derivatives: QSAR study of anti-urease activity, Hirshfeld surface analysis, and DFT calculations

New derivatives of phosphoramido acid with the formula(C6H11NCH3)(NHCOCF3)P(O)(O−)(CH3–+NH2–C6H11)(1) (amidophosphoricacid), (C6H5)2P(O)(O−)(+NH3–C6H4–NH2)(2) (phosphonicacid), (C6H5O)2P(O)(O−)(+NH3–C6H4–NH2) (3) (phosphoricacidester) were synthesized and characterized by X-ray crystallography. The asymmetric unit of compounds 1–3consists of one molecule with the P atom in a tetrahedral environment. The X-ray structural analysis showed that the H-bond patterns depend on the kind of atoms linked to the P atom. In the crystal packing of compound 1, P(O)···H–N and C(O)···H–N hydrogen bonds in 3and P(O)···H–N distances in compounds 2 and 3 led to a one-dimensional arrangement. The energy of P–O···H–N hydrogen bond (EHB) model and stabilizing energies (E2) were calculated. Hirshfeld surface analysis demonstrated that the C···H contact is attributed to CH···πcontact in the 2 and 3 compounds and the F···H contact is referred to hydrogen bond in one O···H counterion interaction. Quantitative structure–activity relationship (QSAR) was used to comprehend the relationship between molecular structural features and the inhibitory of investigated compounds. The use of density functional theory along with the QSAR model for enzymes revealed the importance of QHparameter in describing the anti-AChE and anti-urease activities of monophosphoramidates including P(O)–NH2moiety.