Synthesis and Coordination Properties of 1-(Diphenylphosphine oxide)-1-(2‘-pyridyl N-oxide)-3-(diphenylphosphine oxide)propane

The title trifunctional ligand has been prepared, and coordination chemistry with La(III), Pr(III), and Yb(III) has been examined to assess the ligand's chelation properties. In 1:1 complexes, the ligand binds in a bidentate mode to the Ln(III) ions through the pyridyl N-oxide group and unexpectedly with the “long-arm” phosphine oxide group. The “short-arm” phosphine oxide group points away from the primary chelate ring and forms a monodentate bridge bond to the Ln(III) ion in a second Ln(L)(NO3)3 unit.