Synthesis and 4f 4f absorption studies of tris(acetylacetonato)praseodymium(III) and holmium(III) complexes with imidazole and pyrazole in non-aqueous solvents. Structure elucidation by Sparkle / PM7

Diverse Coordination Numbers and Geometries in Pyridyl Adducts of Lanthanide(III) Complexes Based on β-Diketonate

“…Studying the luminescence of the tris(β-ketonato) Tb ( 9) and tetrakis(β-ketonato) Eu (10) complexes revealed efficient energy transfer in the visible region from the ligands to the central Ln(III) ion. Similar luminescent emission trend was observed in the UV and visible regions in other related β-ketonate derivatives [24][25][26][57][58][59][60][61]. However, it should be mentioned that incorporating strong chelating polypyridyl ligands into the Ln(III)-tris(βketonato) significantly enhances the emission luminescent properties of the compounds in the visible and NIR regions [25,62].…”

“…When excess Hfta is used, the tetrakis(β-ketonato) anionic complex (Hpy)[Eu(btfa) 4 ] (10) was isolated. This trend in reactions of Ln(III) salts and β-diketonate derivatives seems to be universal, where many compounds and pyridyl adducts of similar structural formulas have been isolated and structurally characterized [24][25][26]31,[57][58][59][60][61].…”

Magnetic and Luminescence Properties of 8-Coordinated Pyridyl Adducts of Samarium(III) Complexes Containing 4,4,4-Trifluoro-1-(naphthalen-2-yl)-1,3-butanedionate

“…Similar to most of the Ln 3+ ions, the reaction of an aqueous or alcoholic Ln(III) salts with β-diketonate ligands (ntfa = 4,4,4-trifluoro-1-(naphthalen-2-yl)-1,3-butanedionate; btfa = 4,4,4-trifluoro-1-phenyl-1,3-butanedionate; acac = acetylacetonate) in the presence of three equivalents of NaOH affords the tris β-diketonate complexes [Ln(β-diketonate) 3 (Solv) 2 ] (Solv = H 2 O, MeOH, EtOH) [29][30][31][32][33]. These compounds serve as precursors for the synthesis of many mononuclear polypyridyl adducts, with CNs varying between 8 in the cases of dipyridine derivatives such as phen, bipy, 4,4 -Me 2 bipy, and 5,5 -Me 2 bipy, and 9 in the case of terpy [26,27,[29][30][31][32][33]. With no exception, four samarium(III) complexes [Sm(ntfa) 3 (MeOH) 2 ] (1), [Sm(ntfa) 3 (bipy) 2 ] (2), [Sm(ntfa) 3 (4,4 -Me 2 bipy) 2 ] (3), and [Sm(ntfa) 3 (5,5 -Me 2 bipy) 2 ] (4) were synthesized, and their single-crystal X-ray structures were determined.…”

“…According to the HSAB concept, lanthanide cations (Ln 3+ ) are classified as hard Lewis acids, and as a result, they exhibit strong binding affinity for hard Lewis bases including those containing O-donor ligands such as β-diketone compounds, where tris(β-diketonate) species are most likely formed [20][21][22][23][24][25][26][27][28][29][30][31][32][33]. The resulting complexes show a high tendency to expand their coordination numbers (CNs) from 6 to 9, and in some cases up to 12, through further interaction with various solvent molecules and/or auxiliary ligands such as hetero-atomic molecules [26][27][28][29][30][31][32][33][34][35][36], where the resulting coordinated β-diketonates act as efficient "antenna ligands" for lanthanides emitting in the UV, visible, and NIR region . It has been stated that luminescence efficiency of the β-diketonate complexes can be enhanced by the appropriate choice of the Ln 3+ ion and a combination of aromatic and fluorinated alkyl groups into the β-diketone ligands.…”

Structural Characterization, Magnetic and Luminescent Properties of Praseodymium(III)-4,4,4-Trifluoro-1-(2-Naphthyl)Butane-1,3-Dionato(1-) Complexes

“…Although the intermolecular interaction forces of Ln 3+ with chelated ligand(s) are electrostatic in nature, steric factors rather than electronic ones [44] dominate the geometry of the complexes and as a result, the Ln 3+ complexes containing the same ligand are usually all isostructural. The interactions of β-diketonato ligands with Ln 3+ produces thermodynamically stable complexes [9,17,40,41,43,[45][46][47][48], where the coordinated βdiketonates act as efficient antenna ligands for lanthanides emitting in the visible and NIR region [1][2][3][4]6,17,36]. The resulting Ln(III)-β-diketonates complexes may display coordination numbers (C.N.)…”