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.