title: Structure and NIR-luminescence of ytterbium(III) beta-diketonate complexes with 5-nitro-1,10-phenanthroline ancillary ligand: assessment of chain length and fluorination impact.
abstract: Seven new tris(β-diketonear-nate)ytterbium(III) complexes with the general formula [Yb(β-diketonate)3(5NO2phen)] (where the β-diketone is either 4,4,4-trifluoro-1-(2-naphthyl)-1,3-butanedione, 4,4,4-trifluoro-1-(2-furyl)-1,3-butanedione, 1,1,1-trifluoro-2,4-pentanedione, 1,1,1-trifluoro-5,5-dimethyl-2,4-hexanedione, 1,1,1,5,5,6,6,7,7,7-decafluoro-2,4-heptanedione, 2,4-hexanedione or 2,6-dimethyl-3,5-heptanedione, and 5NO2phen = 5-nitro-1,10-phenanthroline) were synthesized and characterized by elemental analysis, attenuated total reflectance Fourier transform infrared spectroscopy and photoluminescence spectroscopy. Single crystal X-ray structures have been determined for three fluorinated complexes and ground state geometries of the other four complexes have been predicted using the Sparkle/PM6 model. These experimental structures and those designed by semi-empirical models reveal octacoordination around the Yb(3+) ion. Photoluminescence studies and lifetime measurements show that the increase in the fluorinated β-diketonate chain length is associated with a decrease in Yb(3+) luminescence intensity of the (2)F5/2→(2)F7/2 transition at around 980 nm and the (2)F5/2 excited state lifetime, while the ligand lifetime value remains almost unaffected. Finally, fluorination of the ligands is only advised when the complexes are to be used for co-doping with isostructural Er(3+) complexes for optical amplifiers, since it leads to a slight decrease in luminescence intensity for the same β-diketonate chain length.
authors.affiliation: Dpto. de Teoría de la Señal y Comunicaciones e IT, ETSIT, Universidad de Valladolid, Campus Miguel Delibes, Paseo Belén 15, 47011 Valladolid, Spain.
authors.forename: Pablo
authors.initials: P
authors.lastname: Martín-Ramos
authors.forename: Pedro S
authors.initials: PS
authors.lastname: Pereira da Silva
authors.forename: Victor
authors.initials: V
authors.lastname: Lavín
authors.forename: Inocencio R
authors.initials: IR
authors.lastname: Martín
authors.forename: Fernando
authors.initials: F
authors.lastname: Lahoz
authors.forename: Pedro
authors.initials: P
authors.lastname: Chamorro-Posada
authors.forename: Manuela Ramos
authors.initials: MR
authors.lastname: Silva
authors.forename: Jesús
authors.initials: J
authors.lastname: Martín-Gil
mesh_terms: D018360:Crystallography, X-Ray; D007659:Ketones / Q000737:chemistry*; D008024:Ligands; D049449:Luminescence; D008163:Luminescent Measurements; D008958:Models, Molecular; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D010618:Phenanthrolines / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D015018:Ytterbium / Q000737:chemistry*
chemical_list: C524452:5-nitro-1,10-phenanthroline; D007659:Ketones; D008024:Ligands; D009942:Organometallic Compounds; D010618:Phenanthrolines; D015018:Ytterbium