Lanthanide complexes of related click tripodal 1,2,3-triazole-containing ligands on the Ph₃P(O) platform. The N² and N³ coordination of triazole fragments

Abstract

The coordination and extraction properties of two related tripodal ligands differed by types of addition of the triazole fragment and linker length in the {2-[(4-Ph-1,2,3-triazol-1-yl)CH2CH2O]C6H4}3P(O) (L1) and {2-[(1-Ph-1,2,3-triazol-4-yl)CH2O]C6H4}3P(O) (L2) are compared. The structures of the complexes [Lа(NO3)3L1] (I) and [Lu(NO3)3L1] (II) are studied in the solid phase (elemental analysis, IR and Raman spectroscopy) and in solutions (IR and multinuclear1H,13C, and31P NMR spectroscopy). A normal coordinate analysis at the TPSS-D4/Def2-SVP level is performed for an isolated molecule of the model complex [La{P(O),N3,N2-L3}(O,O-NO3)3] (L3= {2-[(4-Me-1,2,3-triazol-1-yl)CH2CH2O]C6H4}3-P(O)). According to the set of spectral and quantum chemical data, ligand L1exhibits the tridentate P(O),N2,N2coordination in lanthanide complexes I and II. These are neutral complexes in the solid state and in CD3CN solutions, and the dynamic equilibrium of the neutral and ionic complexes is observed in CDCl3. Unlike ligand L1, ligand L2exhibits the tetradentate P(O),N3,N3,N3coordination in the [Ln(NO3)3L2] complexes with the same metals (Ln = La3+, Lu3+) in solutions. The efficiency of extraction of microquantities offelements from the aqueous phase to 1,2-dichloroethane by compounds L1and L2is discussed in comparison with the structures of the complexes of both ligands in solutions.