Fluorescence and energy transfer properties of heterometallic lanthanide-titanium oxo clusters coordinated with anthracenecarboxylate ligands

Abstract

Two 9-anthracenecarboxylate (9-AC) coordinated heterometallic TOC compounds, [Ln2Ti10O14(ClO4)2(O(i)Pr)14(9-AC)2(CH3CN)2]·2H2O, Ln = Nd 1() and Eu (2), along with two benzoate (bza) analogues, [Ln2Ti10O14(ClO4)2(O(i)Pr)14(bza)2(HO(i)Pr)2], Ln = Nd (3) and Eu (4), were prepared by one step in situ solvothermal synthesis, and characterized by single crystal analysis. To date, only about ten lanthanum-titanium oxo clusters have been reported. Except for two Ti28 clusters, the compounds are all small clusters (Ti ≤ 4). The cluster structures of 1-4 adopt a Ti10Ln2 core structure with pseudo-Ci symmetry, which is similar to the fundamental structure of Ti12 clusters. Furthermore, except for their structures, the properties of lanthanum-titanium oxo clusters have never been studied. Herein, the fluorescence properties of these compounds are studied in detail. The metal centered emission of Eu(III) is completely quenched by 9-AC due to the lower triplet energy of the coordinated ligand. Enhanced ligand centered fluorescence is found for 2 in comparison with that of 1.

Synthesis, structure and properties of the manganese-doped polyoxotitanate cage [Ti18MnO30(OEt)20(MnPhen)3] (Phen = 1,10-phenanthroline)

“…Resembling the fragments of bulk TiO 2 , molecular polyoxotitanate (POT) cages of the type [Ti x O y (OR) z ] and metal-doped cages (M-POT) [Ti x O y (OR) z (M) n ] have well-defined inorganic Ti x O y cores and can be seen as models for the study of structural chemistry of bulk TiO 2 , such as its crystal growth, 4,5 the binding of surface sensitizers, [6][7][8][9][10][11][12][13][14] and the electronic and struc-tural effects of heterometallic doping. [15][16][17][18][19][20][21][22][23][24][25][26][27] These cages also possess hydrolysable organic alkoxy ligand peripheries and can function as single-source precursors for the solution deposition of TiO 2 and metal-doped TiO 2 .…”

Synthesis, Photophysical Properties, and Metal-Ion Recognition Studies of Fluoroionophores Based on 1-(2-Pyridyl)-4-Styrylpyrazoles

“…The relative quantum yields of 3a – 3d and 4a – 4d were determined by using quinine sulfate (φ F = 0.59 in 1.5 × 10 –1 M HClO 4 ) as reference and calculated according to the following equation. − where x and st indicate the sample and standard solution, respectively, φ is the quantum yield, F is the integrated area of the emission, A is the absorbance at the excitation wavelength, and η is the index of refraction of the solvents.…”

Energy transfer and photoluminescence properties of lanthanide-containing polyoxotitanate cages coordinated by salicylate ligands

“…In 2015, Wang et al studied the photoluminescence behaviour of anthracenecarboxylate-modified Ln-POT cages (with Ln 2 Ti 10 cores, Ln = Eu and Nd) and investigated the energy transfer process between the ligands and the Ln 3+ centres. 26 In 2016,…”