Synthesis, selected coordination chemistry and extraction behavior of a (phosphinoylmethyl)pyridyl N-oxide-functionalized ligand based upon a 1,4-diazepane platform

Syntheses for the new multidentate chelating ligands ((6,6′-((1,4-diazepane-1,4-diyl)bis(methylene))bis(pyridine-6,2-diyl))bis(methylene))bis(diphenylphosphine oxide) (2) and 6,6′-((1,4-diazepane-1,4-diyl)bis(methylene))bis(2-((diphenylphosphoryl)methyl)pyridine 1-oxide) (3), based upon a 1,4-diazepane platform functionalized with 2-(diphenylphosphinoylmethyl)pyridine P-oxide and 2-(diphenylphosphinoylmethyl)pyridine N,P-dioxide fragments, respectively, are reported. Results from studies of the coordination chemistry of the ligands with selected lanthanide nitrates and Cu(BF₄)₂ are outlined, and crystal structures for two complexes, [Cu(2)](BF₄)₂ and [Cu(3)](BF₄)₂, are described along with survey Eu(III) and Am(III) solvent extraction analysis, for 3.