Synthesis, Crystal Structure and Hirshfeld Surface (HS) Analysis of Two New Phosphoric Triamides: A Comparison of HSs for Structures with Different Molecular Assemblies

Abstract

Two new phosphoric triamides, N-(2-chloro-5-fluorobenzoyl)-N′,N"-bis(morpholin-4-yl)-phosphoric triamide, (2-Cl,5-F-C₆H₃C(O)NH)P(O)(NC₄H₈O)₂, 1, and N,N′-dibenzyl-N"-(2-chloro-5-fluorobenzoyl)-N,N′-diethylphosphoric triamide, (2-Cl,5-F-C₆H₃C(O)NH)P(O)(N(C₂H₅)(CH₂C₆H₅))₂, 2, were synthesized and characterized by ¹H-, ¹³C-, ³¹P-, ¹⁹F-NMR and IR spectroscopies and single-crystal X-ray diffraction analysis. Different orientations of P(O) versus NH, anti in 1 and syn in 2, lead to different hydrogen bond patterns, mediated by N–H⋯O, as a linear arrangement forming a C(4) motif and a dimeric aggregate with an $R_{2}^{2}\left( 8 \right)$ ring motif, respectively. The crystal packing of both compounds present a three-dimensional supramolecular assembly, made by the cooperation from weak intermolecular interactions, C–H⋯O and C–H⋯π, for 1 and 2, and π⋯π for 2. Hirshfeld surface analysis demonstrates that the H⋯H contacts are decisive for both structures with contribution portions of 39.1% for 1 and 49.6% for 2. The O⋯H/H⋯O (1: 24.4% and 2: 9.6%) contacts are the characteristic intermolecular interactions, showing a pair of sharp spikes; while C⋯H/H⋯C contacts (1: 11.3% and 2: 21.7%), associated to the π⋯H/H⋯π interactions, can be illustrated as wings in the corresponding fingerprint plots. The C⋯C contacts are revealed for 2 (1.6%), associated to π⋯π interaction observed in the X-ray analysis.

Graphical Abstract

Two phosphoric triamides with the same [C(O)NH]P(O)[N(C)(C)]₂ skeleton but with different molecular assemblies were investigated by the analysis of Hirshfeld surfaces and fingerprint plots.