A synthetic route for the formation of 2-[bis(2-trifluoromethylphenyl)phosphinoylmethyl]pyridine N-oxide (1c) and 2-[bis(3,5-trifluoromethylphenyl)phosphinoylmethyl]pyridine N-oxide (1d) was developed and the new ligands characterized by spectroscopic methods and single-crystal X-ray diffraction analyses. The coordination chemistry of 1c was examined with Yb(NO3)3 and the molecular structure of one complex, [Yb(1c)(NO3)3(DMF)].DMF.0.5H2O, was determined by single-crystal X-ray diffraction methods. The ligand is found to coordinate in a bidentate fashion, and this is compared against lanthanide coordination chemistry observed for the related ligand, [Ph2P(O)CH2] C5H4NO.

Phosphinoyl Grignard-based substitutions on 2,6-bis(chloromethyl)pyridine followed by N-oxidation of the intermediate 2,6-bis(phosphinoyl)methylpyridine compounds with mCPBA give the target trifunctional ligands 2,6-bis[bis(2-trifluoromethylphenyl)phosphinoylmethyl]pyridine 1-oxide (2a) and 2,6-bis[bis(3,5-bis(trifluoromethyl)phenyl)phosphinoylmethyl]pyridine 1-oxide (2b) in high yields. The ligands have been spectroscopically characterized, the molecular structures confirmed by single crystal X-ray diffraction methods, and the coordination chemistry surveyed with lanthanide nitrates. Single crystal X-ray diffraction analyses are described for the coordination complexes Nd(2a)(NO(3))(3), Nd(2a)(NO(3))(3) x (CH(3)CN)(0.5), Eu(2a)(NO(3))(3), and Nd(2b)(NO(3))(3) x (H(2)O)(1.25); in each case the ligand binds in a tridentate mode to the Ln(III) cation. These structures are compared with the structures found for lanthanide coordination complexes of the parent NOPOPO ligand, [Ph(2)P(O)CH(2)](2)C(5)H(3)NO.

No abstract

Efficient syntheses for the precursor molecules, 2‐{6‐[((diphenylphosphoryl)methyl)pyridin‐2‐yl]methyl}isoindoline‐1,3‐dione (2), 2‐[(1,3‐dioxoisoindolin‐2‐yl)methyl]‐6‐[(diphenylphosphoryl)methyl]pyridine 1‐oxide (3), and their 6‐[bis(2‐(trifluoromethyl)phenyl)phosphoryl]methyl analogues are reported along with their transformations into the dissymmetric ligands, [(6‐(aminomethyl)pyridin‐2‐yl)methyl]diphenylphosphine oxide (4), 2‐(aminomethyl)‐6‐[(diphenylphosphoryl)methyl]pyridine 1‐oxide (5) and 2‐(aminomethyl)‐6‐{[bis(2‐(trifluoromethyl)phenyl)phosphoryl]methyl}pyridine 1‐oxide (5‐F). Selected reactivity of the aminomethyl substituent of 4 and 5, as well as complexation reactions of several of the compounds with lanthanide(III) ions are described. Molecular structures of three uniquely different complexes, {Pr{2‐[HC(O)N(H)CH2]‐6‐[Ph2P(O)CH2]C5H3NO}(NO3)3(MeOH)}2, {Eu{2‐[(Me2N)2CN(H+)CH2]‐6‐[Ph2P(O)CH2]C5H3N(H)+}(NO3)4(OMe)} and {Er{2‐[(C8H4O2)NCH2]‐6‐[Ph2P(O)CH2]C5H3N(O)}(NO3)3(MeOH)}·(CH3)2CO, have been determined by single‐crystal X‐ray diffraction methods. The observed and computationally modeled structures that employ bidentate and tridentate ligand/metal interactions are compared. These results suggest further ligand modifications that should provide improved solvent extraction reagents.