Synthesis and coordination properties of new bis(phosphinomethyl)pyridine N,P,P '-trioxides

In a search for more hydrocarbon solvent soluble derivatives of the parent ligand, 2,6-[Ph2P(O)CH2](2)C5H3NO (1a), a series of new ligands, 2,6-[R2P(O )CH2](2)C5H3NO [R = Bz (1b); Tol (1c); Et (1d); Pr (1e); Bu (1f); Pn (1g); Hx (1h); Hp (1i); and Oct (1j)] and 2,6-[RR 'P(O)CH2](2)C5H3NO [R = Ph, R ' = Bz (2a); R = Ph, R ' = Me (2b); R = Ph, R ' = Hx (2c); R = Ph, R ' = Oct (2d)], have been prepared by either Arbusov or Grignard substitutions on 2 ,6-bis(chloromethyl)pyridine followed by N-oxidation. The new ligands have been characterized by spectroscopic methods, and their coordination chemist ry with selected lanthanide ions has been surveyed. Several 1:1 and 2:1 lig and/metal complexes have been isolated, and single-crystal X-ray diffractio n analyses for Nd(2a)(NO3)(3), Er(2a)(NO3)(3), Yb(ld)(NO3)(3), and [Nd(1c)( 2)](NO3)(3) are described. The new structural data are discussed in relatio n to the structures of complexes formed by la.