| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1408327 | Journal of Molecular Structure | 2015 | 4 Pages |
•Five mononuclear lanthanide complexes were obtained.•Two distinct ligands were in-situ self-assembled.•Ce3+ ions were oxidized to Ce4+ ions in the reaction mixture.•NIR luminescence of Yb3+ ions was observed.
Self-assembly reaction of 2-aldehyde-8-hydroxyquinoline, tris(hydroxymethyl)aminomethane and LnCl3⋅6H2O affords a series of mononuclear lanthanide complexes Ce(baho)2·Et2O (1) (H2baho = 2,8-bis(2-(8-hydroxylquinolinyl))-1-aza-5-hydroxymethyl-3,7-dioxabicyclo[3.3.0]octane), Dy(nhm)2Cl·0.5H2O (2) and Ln(nhm)2Cl·0.5C6H14 (Ln = Ho (3), Er (4), Yb (5) and Hnhm = N-(2-(8-hydroxylquinolinyl)methylene)(trishydroxymethyl)methylamine. The crystal structures have been determined by X-ray crystallographic analysis, and the tetravalence of Ce in 1 has been proven by XPS. Interestingly, the positive charge of Ce4+ ion in 1 is neutralized by two deprotonated baho2− ligands, while two deprotonated nhm− ligands and one Cl− compensate the positive charge of Ln3+ ions in 2–5. Complex 5 exhibit essential NIR luminescence of Yb3+ ion with lifetime of 17.64 μs in solid and 9.96 μs in CH3OH solution.
Graphical abstractA series of mononuclear lanthanide complexes were isolated and characterized. Cerium was found in tetravalence with an unexpected ligand 2,8-bis(2-(8-hydroxylquinolinyl))-1-aza-5-hydroxymethyl-3,7-dioxabicyclo[3.3.0]octane in 1, in contrast to Ln3+ ions (Ln = Dy (2), Ho (3), Er (4) and Yb (5)) with a Schiff-base ligand. The NIR luminescent behavior of 5 was further investigated.Figure optionsDownload full-size imageDownload as PowerPoint slide
