The spectroscopy and structure of new 1,3,2-diazaphospholes and 1,3,2-diazaphosphorinanes

Article abstract of DOI:10.1080/10426507.2012.743547

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-HcccO hydrogen bonds. The presence of weak intermolecular C-HcccO and C-HcccCl hydrogen bonds creates a three dimensional polymeric chain in the crystal lattice.