Abstract
New 1,3,2-diazaphospholes and 1,3,2-diazaphosphorinanes with formula 2,4-Cl2-C6H3-C(O)NHP(O)X where X = (1), (2), (3), and (4) were synthesized and characterized by 1H, 13C, 31P NMR, IR spectroscopy, and elemental analysis. The 31P NMR spectra revealed that the phosphorus atoms are more deshielded in the diazaphospholes than in the diazaphosphorinanes. The 13C NMR spectrum of 2 indicated that 2JPC(aliphatic) = 14.2 Hz for the endocyclic carbon atom is larger than that for the exocyclic CH3 carbon atom (5.2 Hz). Furthermore, for diazaphosphorinanes, 3JPC(aliphatic) ≈ 2 × 2JPC(aliphatic). The molecular structure of compound 2 was determined by X-ray crystallography. In this structure, a centrosymmetric dimer is formed via connection of two molecules by strong intermolecular N–HċċċO hydrogen bonds. The presence of weak intermolecular C–HċċċO and C–HċċċCl hydrogen bonds creates a three dimensional polymeric chain in the crystal lattice.
GRAPHICAL ABSTRACT
Acknowledgments
The financial support of this work by the Research Council of Tarbiat Modares University is gratefully acknowledged.