New phosphorus (V) – nitrogen compounds: synthesis, spectroscopic characterization and X-ray crystallography studies

Abstract

The phosphoramides [CClF2C(O)NH]P(O)[NC4H8]2 (1), [CF3C(O)NH]P(O)[NHC3H7]2 (2), [(2,3-F2)C6H3C(O)NH]P(O)[NHC6H11]2 (3) and [(2,3-F2)C6H3C(O)NH]P(O)[NHC3H5]2 (4) and thiophosphoramide [(4-Cl)C6H4NH]P(S)[OCH3]2 (5) were synthesized and characterized by NMR and IR spectroscopy, and by single crystal X-ray determination for compounds 1 and 2. Furthermore, the compound [CClF2C(O)NH]P(O)[NH]2C5H10 (6) which was previously studied by spectroscopic methods was further investigated here by X-ray crystallography experiment. For compounds 1 – 4, the 31P signals are revealed in the range of 3.30 – 7.29 ppm and for the thiophosphoramide 5 the 31P signal is appeared at 69.85 ppm. In the 1H NMR experiments of compounds 1 – 4, the NCP—H signals are appeared as broad signals in the range of 8.97 – 10.25 ppm (NCP is the nitrogen atom of the C(O)NHP(O) segment), while, the other N—H signals of compounds 2–5 are appeared in the range of 2.49 – 4.84 ppm. In the crystal structure of compound 1, the dimers are built from pairs of NCP—H…O═P hydrogen bonds. For structure 2, the linear arrangement is formed through alternating eight-membered and twelve-membered cyclic hydrogen-bonded motifs, the former is built from a pair of NCP—H…O═P hydrogen bonds and the latter from a pair of N—H…O═C hydrogen bonds. In the crystal structure of compound 6, the molecules are aggregated through NCP—H...O═P and N―H...O═C hydrogen bonds, building a 2D arrangement along the bc plane.