Synthesis and structural study of five new phosphoric triamides: interplay between classical and non-classical intermolecular interactions
Résumé
Abstract Phosphoric triamides are attractive to investigate because of their extensive applications in various fields, especially in medicine. Five new phosphoric triamides with the main parts [N]P(O)[NH] 2 and [C(O)NH]P(O)[N] 2 have been structurally analyzed by single crystal MoKα/synchrotron-based X-ray diffraction and characterized by spectroscopic methods (FT-IR and 1 H, 13 C, 31 P NMR). Compounds crystallize in orthorhombic ( 1 with space group Pnma ) and monoclinic ( 2 ( P 2 1 / a ), 3 ( C 2/ c ), 4 ( P 2 1 / n ) and 5 ( P 2 1 / c )) crystal systems. The asymmetric unit of all structures consists of one phosphoric triamide molecule, except for 1 with one half of molecule. X-ray crystallography data reveal that the molecular architectures constructed by classical N—H … O hydrogen bonds are as 1D linear (building the R 2 1 ( 6 ) ${R}_{2}^{1}\left(6\right)$ , C (4) and R 2 2 ( 10 ) / R 2 1 ( 6 ) ${R}_{2}^{2}\left(10\right)/{R}_{2}^{1}\left(6\right)$ motifs, respectively, for 1 – 3 ) or dimeric (the R 2 2 ( 8 ) ${R}_{2}^{2}\left(8\right)$ ring motif for 4 and 5 ). A detailed investigation of the intermolecular interactions using Hirshfeld surface (HS) analysis illustrates that the H … H, O … H/H … O and C … H/H … C contacts for all compounds, and Cl … H/H … Cl and F … H/H … F contacts for 3 – 5 , are the most significant contributors to the crystal packing. Moreover, based on the calculated enrichment ratios ( E ), the O … H/H … O contacts including the classical N—H … O hydrogen bonds for all structures are considered as favoured contacts.