Preparation, crystal structure, and luminescent properties of CAPh containing lanthanide(III) complexes with various amounts of coordinated solvent molecules

Abstract

A series of mixed–ligand lanthanide complexes, Ln(Pip)₃(ⁱPrOH)_x (x = 2 for Ln(III) = La, Ce–Nd, Sm–Eu and x = 1 for Ln(III) = Gd–Lu; HPip is 2,2,2-trichloro-N-(dipiperidin-1-yl-phosphoryl)acetamide, the carbacylamidophosphate (CAPh) ligand), has been synthesized and identified. Using indirect techniques (FT-IR, ¹H, ³¹P-NMR, and absorption spectroscopy) and the X-ray diffraction method (for europium complex) it was found that three Pip^-ligands are coordinated to lanthanide(III) ions in a bidentate chelate manner via oxygen atoms of the carbonyl and phosphoryl groups. The oxygen atoms of 2-propanol molecules complete the coordination number of Ln(III) ions to eight (for Ln from La to Eu) or seven (for Ln from Gd to Lu). The europium complex Eu(Pip)₃(ⁱPrOH)₂ crystallizes in the Рī space group. The {EuO₈} polyhedron has a triangular dodecahedron (TDD-8) conformation and exists in a form of a t₁t₂p₂+MC isomer. The luminescent properties of Eu(Pip)₃(ⁱPrOH)₂ polycrystalline samples were investigated at 300, 77, and 4.2 K.

Graphcial Abstract

Keywords:

• Carbacylamidophosphate (CAPh)
• chelating ligand
• solvatocomplex
• lanthanide
• europium
• luminescence
• absorption spectra
• infrared spectra

Acknowledgments

This research was supported by the Ministry of Education and Science of Ukraine (grant nos. 19BF037-05 and 22BF037-04). The authors sincerely thank all brave defenders of Ukraine that made finalizing this publication possible.

Disclosure statement

No potential conflict of interest was reported by the authors.