Synthesis, X‐ray Crystallography, and DFT Calculations of A Novel Phosphoramide

Abstract

A new phosphoramide with formula (4‐CH3C6H4S(O)2NH)P(O)(NHCH2C6H5)2 (1) was synthesized and characterized by 1H, 13C, 31P NMR, FT‐IR spectroscopy, and elemental analysis. The 13C NMR spectrum displays two sets of signals for the phenyl carbon atoms of the two benzylamine groups (eight peaks) as well as two separated signals for the 4‐CH3 aliphatic carbon atom possibly due to the presence of a prochiral central phosphorus atom. The structure of compound 1 was determined by X‐ray crystallography at 121 K. In this structure, the strong intermolecular N–H···O=P and N–H···O=S plus weak intermolecular C–H···O and N–H···C(π of benzyl ring) hydrogen bonds create a three‐dimensional crystalline network. The DFT calculations both in the gas phase and in four solvents illustrate that this molecule is more stable at B3PW91 than B3LYP level. Interestingly, comparable computational results are obtained in acetone and methanol solvents as well as in DMSO and ethanol. The QTAIM analyses support the covalent/shared character of the C–N, S–C, and N–H bonds, the intermediate character of P=O, P–N, and S=O bonds, and the electrostatic nature of S=O···H–N, P=O···H–C, and C–H···C(π) interactions. The computational data are in very good agreement with the experimental ones.