Photoluminescent One‐Dimensional Coordination Polymers from Suitable Pyridine Antenna and LnCl₃ for Visible and Near‐IR Emission

Abstract

The series of one-dimensional coordination polymers ϱ 1 [LnCl 3 (bipy)(py) 2 ]·py [bipy = 4,4Ј-bipyridine, py = pyridine; Ln = Gd, Tb, Dy, Ho, Er, Yb] as well as ϱ 1 [Lu 2 Cl 5 (bipy) 2 (py) 4 ]ϱ 1 [LuCl 4 (bipy)] were synthesized by the reactions of anhydrous LnCl 3 with bipy and py. The formation of extended zigzag chains and saltlike band structures with cationic and anionic strands is observed. Pyridine and 4,4Ј-bipyridine ligands serve as suitable antennas for lanthanide-based luminescence in the visible and near-infrared range through effective sensitization by the ligands followed by emission

Thiazole and the Diazines Pyrazine and Pyrimidine as Sensitizers for Lanthanide Luminescence from VIS to NIR

“…This is in good accordance e.g. with 1 ϱ [ErCl 3 (bipy)(py) 2 ]•py [19] showing Er-N distances from 247.3 6) pm for the bridging Cl atoms. This is in accordance, e.g.…”

Self-Assembly Syntheses, Structural Characterization, and Luminescent Properties of Lanthanide Coordination Polymers Constructed by Three Triazole-Carboxylate Ligands

“…Under excitation at 321 nm, complexes 2 , 6 , and 11 display the characteristic red luminescence of Eu 3+ ions with similar emission bands among the 500–750 nm region and maximum intensities at 590 nm, 614 nm, 650 and 699 nm, arising from the 5 D 0 → 7 F J ( J = 1–4) transitions, respectively. The absence or weak intensity of ligand-centered emissions in 400–450 nm demonstrates that the energy adsorbed by three ligands can be transferred to the emitting levels of Eu 3+ centers efficiently. , According to the ED rule, , the symmetry forbidden transition between 5 D 0 and 7 F 0 is only involved with the site symmetry of C s , C n and C nv . The presence of the 5 D 0 → 7 F 0 transitions in the emission spectra of Eu 3+ complexes indicates a fact that the Eu 3+ centers in complexes 2 , 6 , and 11 locate the sites free from inversion symmetry, which matches with the results of X-ray crystallographic analysis.…”

“…It may be ascribed to the π···π stacking interactions between partially overlapping aromatic rings in the two complexes, which may make conjugated chromophores closer to each other and induce electronic interactions, resulting in the enhancement of the observed luminescence lifetimes consequently. , Furthermore, compared with the other four complexes, the obvious variation of lifetimes between 298 and 77 K are observed in complexes 6 and 8 , with the values up to 0.93 and 1.16 ms at 77 K respectively. It may be ascribed to the existence of notable thermal-activated deactivation processes, , such as back energy transfer or other thermodynamic interactions.…”

“…The absence or weak intensity of ligand-centered emissions in 400−450 nm demonstrates that the energy adsorbed by three ligands can be transferred to the emitting levels of Eu 3+ centers efficiently. 60,61 According to the ED rule, 62,63 the symmetry forbidden transition between 5 D 0 and 7 F 0 is only involved with the site symmetry of C s , C n and C nv . The presence of the 5 D 0 → 7 F 0 transitions in the emission spectra of Eu 3+ complexes indicates a fact that the Eu 3+ centers in complexes 2, 6, and 11 locate the sites free from inversion symmetry, which matches with the results of X-ray crystallographic analysis.…”

“…72,73 Furthermore, compared with the other four complexes, the obvious variation of lifetimes between 298 and 77 K are observed in complexes 6 and 8, with the values up to 0.93 and 1.16 ms at 77 K respectively. It may be ascribed to the existence of notable thermal-activated deactivation processes, 62,63 such as back energy transfer or other thermodynamic interactions. Quantum yield (Φ) is also a significant parameter to estimate the efficiency of sensitized emission process from the ligand to Ln 3+ centers.…”