Novel P,P-diphenylphosphinic amide-TEMPO radicals family: Synthesis, crystal structures, spectroscopic characterization, magnetic properties and DFT calculations

Abstract A new family of three P , P -diphenylphosphinic amide-TEMPO radicals with general formula (C 6 H 5 ) 2 P( X )-NH-TEMPO, X  = O ( 1 ), S ( 2 ) and Se ( 3 ) were obtained by reaction of chlorodiphenylphosphine with 4-amino-2,2,6,6-tetramethylpiperidine-1-oxyl radical (NH 2 -TEMPO) and subsequent oxidation with H 2 O 2 and elemental sulfur or selenium. These radicals were characterized by UV–Vis, FT-IR and 1 H, 31 P and 77 Se nuclear magnetic resonance spectroscopy. The crystal structures of all radicals were determined by single-crystal X-ray diffraction. The magnetic study of all diphenylphosphinic amide-TEMPO radicals reveals very weak intermolecular ferromagnetic interactions. Density functional theory (DFT) calculations have been also performed to support the interpretation of magnetic properties and electronic structure.