Uranium complexes of cyclic O,O-bidentate ligands with the P-N-P backbone

► Phosphorylated 1,2-azaphospholanes form O-monodentate or O,O-bidentate uranium complexes. ► The structure of the complex depends on the difference of donor properties of the O-atoms of phosphoryl groups. ► In solutions monodentate complexes undergo dimerization and insertion of air oxygen affording (μ2-peroxo)-bridged complexes. ► The ligands bearing two asymmetric phosphorus atoms were used as individual diastereomers.