Synthesis and coordination chemistry of arene soluble 4-alkyl-2,6-bis[(diphenylphosphino)methyl]pyridine N,P,P′-trioxide ligands

Abstract

The trifunctional ligand 2,6-[(C₆H₅)₂P(O)CH₂]₂C₅H₃NO forms stable complexes with trivalent and tetravalent f-element cations and it acts as an effective liquid–liquid extraction reagent when it is dissolved in CHCl₃. In a search for more hydrocarbon solvent soluble extraction reagents, derivative ligands having alkyl substituents in the 4-pyridyl ring position, 4-R′-2,6-[(C₆H₅)₂P(O)CH₂]₂C₅H₂NO (R′ = Et, Oct), have been prepared and characterized. A single crystal X-ray diffraction analysis for the Et derivative shows that the ligand molecular structure is closely related to the parent ligand, 2,6-[(C₆H₅)₂P(O)CH₂]₂C₅H₃NO. The coordination chemistry of the ligands with Nd(NO₃)₃ has been examined, and the molecular structures of two complexes obtained with 1 ∶ 1 and 2 ∶ 1 ligand ∶ metal reactant ratios are reported.