Synthesis and lanthanide coordination chemistry of 2-[(phosphinoyl)methyl]-4,5-dihydrooxazole and 2-[(phosphinoyl)methyl]benzoxazole ligands

Syntheses for [(diphenylphosphinoyl)methyl]-4,5-dihydrooxazole (2) and [(diarylphosphinoyl)methyl]benzoxazoles [aryl = phenyl (3), tolyl (4), 2-trifluoromethylphenyl (5) and 3,5-bis(trifluoromethyl)phenyl (6)] have been developed. Each ligand has been characterized by spectroscopic methods and single crystal X-ray diffraction analyses have been completed for 2, 3, 4 and 5. The coordination chemistry of the ligands with Nd(NO3)3 and Yb(NO3)3 has been examined and structure determinations for [Nd(2)2(NO3)3(CH3OH)], [Nd(2)2(NO3)3], [Yb(3)2(NO3)3(H2O)]·0.5(CH3OH), [Nd(3)2(NO3)3]·3(CHCl3), [Nd(4)2(NO3)3(H2O)], [Yb(4)2(NO3)3(H2O)] and [Yb(5)2(NO3)3(H2O)]·0.5(CH3CN) are reported. Depending upon conditions, the ligands act as monodentate PO or bidentate, chelating PO,N donors.

Graphical abstractGeneralized syntheses for [(phosphinoyl)methyl]-4,5-dihydrooxazole and [(phosphinoyl)methyl]benzoxazole ligands are reported as well as selected coordination chemistry with lanthanide nitrates. Crystal structure analyses indicate that the ligands can adopt either monodentate or bidentate coordination modes in the solid state depending upon synthetic conditions.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► New (phospinoyl)methyl dihydrooxazole and benzoxazole ligands have been prepared and structurally characterized. ► Lanthanide coordination chemistry. ► Crystal structure analyses reveal ligand coordination mode selection.