Synthesis and X−ray structures of thioxo− and selenoxo−phosphino species derived from monooxidation of new N-(4-acetylphenyl)-P, P-diphenylphosphinous amide ligand

The reaction of p-acetylaniline with chlorodiphenylphosphine afforded the new ligand (p-CH₃CO)C₆H₄N(H)PPh₂ (1) in good yield. Monooxidized thioxo (p-CH₃CO)C₆H₄N(H)P(S)Ph₂ (2) and selenoxo (p-CH₃CO)C₆H₄N(H)P(Se)Ph₂ (3) were synthesized by the reaction of 1 with elemental sulfur or grey selenium. Compounds 1–3 were identified and characterized by multinuclear NMR spectroscopy (¹H, ¹³C, ³¹P, ⁷⁷Se NMR) and elemental analysis. Compounds 2 and 3 were structurally characterized by single crystal X-ray diffraction which showed that the p-acetyl substituent on the aniline aromatic ring has a profound influence on the elongation of the P−N bond distance compared to several structurally characterized analogues found in literature. As such, subsequent reactions involving the P-N bond (i.e. insertion reactions) may be influenced in a favorable manner and proceed with ease.